Comparative before-after study of fever prevention versus targeted temperature management following out-of-hospital cardiac arrest

Background

International guidelines for neuroprotection following out-of-hospital cardiac arrest (OHCA) recommend fever prevention ahead of routine temperature management. This study aimed to identify any effect of changing from targeted temperature management to fever prevention on neurological outcome following OHCA.

Methods

A retrospective observational cohort study was conducted of consecutive admissions to an ICU at a tertiary OHCA centre. Comparison was made between a period of protocolised targeted temperature management (TTM) to 36 °C and a period of fever prevention.

Results

Data were available for 183 patients. Active temperature management was administered in 86/118 (72%) of the TTM cohort and 20/65 (31%) of the fever prevention group. The median highest temperature prior to the start of temperature management was significantly lower in the TTM group at 35.6 (IQR 34.9-36.2) compared to 37.9 °C (IQR 37.7-38.2) in the fever prevention group (adjusted p < 0.001).There was no difference in the proportion of patients discharged with Cerebral Performance Category 1 or 2 between the groups (42% vs. 40%, p = 0.88). Patients in the fever prevention group required a reduced duration of noradrenaline (36 vs. 46 h, p = 0.03) and a trend towards a reduced duration of propofol (37 vs. 56 h, p = 0.06).In unadjusted analysis, use of active temperature management (irrespective of group) appeared to be associated with decreased risk of poor outcome (OR = 0.43, 95% CI 0.23-0.78) but after adjustment for patient age, presenting rhythm, witnessed arrest and duration of CPR, this was no longer significant (OR = 0.93, 95% CI 0.37-2.31, p = 0.88).

Conclusion

Switching from TTM to fever prevention following OHCA was associated with similar rates of neurological outcomes, with a possible decrease in sedation and vasopressor requirements.

Use of mechanical circulatory support in patients with non-ischemic cardiogenic shock

Background

The aim of this study was to evaluate mechanical circulatory support (MCS) for the treatment of non-ischemic cardiogenic shock (CS).

Methods

Data from 1,030 consecutive patients with non-ischemic CS treated with or without MCS at 16 tertiary-care centers were retrospectively collected. The association between MCS and 30-day mortality was assessed in a 1:1 propensity score matched cohort.

Results

MCS was used in 406 (39%) patients. MCS treated patients presented with more severe CS (lactate 5.4 vs. 4.1 mmol/l, systolic blood pressure 80 vs. 83 mmHg, higher SCAI class) and with more disease modifiers (prior cardiac arrest 42.4 vs. 36.1%, mechanical ventilation 78.4 vs. 56.5%). After matching, 272 patients treated with were compared vs. 272 patients treated without MCS. MCS was associated with a lower 30-day mortality (hazard ratio 0.77, 95% confidence interval 0.60–0.98, Figure 1). This finding was consistent through all tested sub-groups except when ejection fraction was considered, indicating an association especially in patients with an ejection fraction ≤20%. Complications occurred more frequently in patients with MCS; e.g. severe bleedings (21.8 vs. 9.2%) and access-site related ischemia (6.6 vs. 0%).

Conclusion

In patients with non-ischemic CS, MCS use was associated with lower 30-day mortality as compared to medical therapy only, particularly in patients with a lower ejection fraction. This provides rationale for randomized trials to validate these findings.

Funding Acknowledgement

Type of funding sources: None.

Impact of left ventricular ejection fraction on mortality and use of mechanical circulatory support in non-ischaemic cardiogenic shock

Background

Evidence in non-ischaemic cardiogenic shock (CS), especially regarding prognostic markers and use of mechanical circulatory support (MCS), is scarce.

Aim

The aim of this study was to evaluate left ventricular ejection fraction (LVEF) as a prognostic marker as well as a factor to guide the use of MCS in non-ischaemic CS.

Methods

In this international observational study, patients with non-ischaemic CS (e.g. caused by severe de-novo or acute on chronic heart failure; but not by acute myocardial infarction) treated with or without MCS from 18 tertiary-care centers in five countries were enrolled. Cox regression models adjusted for age, sex, SCAI class, lactate, prior resuscitation, mechanical ventilation and pH were fitted to evaluate the association between LVEF and 30-day mortality as well as the interaction between MCS use, LVEF and 30-day mortality.

Results

A total of 807 patients were enrolled, of whom 387 (47,9%) were treated with and 418 (52.1%) without MCS; mean age was 63 [interquartile range (IQR) 51.5–72) years, 601 (74.5%) were male, 486 (60.2%) had acute on chronic heart failure, 221 (32.7%) had an ischaemic cardiomyopathy and 277 (34.5%) had prior cardiac arrest. The baseline LVEF was 20 (IQR 15–30) % and baseline lactate was 4.9 (IQR 2.6–8.5) mmol/l.

There was no significant association between LVEF and 30-day mortality risk [hazard ratio (HR) 0.95, 95% confidence interval (CI) 0.74–1.22 if LVEF was considered as a continuous variable; HR 1.09, 95% CI 0.83–1.44 if LVEF was considered as a categorical variable with ≤20% vs. &gt;20%]. However, there was a significant interaction between MCS use and LVEF, indicating a lower 30-day mortality risk with MCS use in patients with a depressed LVEF (HR 0.74, 95% CI 0.52–1.05, interaction-p = 0.04).

Conclusion

In this retrospective, multicenter, international study of patients with non-ischaemic CS, LVEF was not a predictor of 30-day mortality risk. However, we observed a significant interaction between MCS use and LVEF, indicating a lower morality risk with MCS use only in patients with a depressed LVEF. This provides rationale to use LVEF as a parameter to guide MCS therapy in non-ischaemic CS, and calls for a randomized trial on this topic.

Funding Acknowledgement

Type of funding sources: None.

P2671The addition of admission lactate to the CREST risk score to determine prognosis in out of hospital cardiac arrest: the C-AREST score

Introduction

There has been an increasing focus on the development of scoring systems for patients admitted following resuscitation from out-of-hospital cardiac arrest (OHCA) to determine both prognosis and short-term management. One such system, the CREST score, has been shown to predict circulatory aetiology death in patients without ST-elevation myocardial infarction, however with an increasing number of OHCAs seen, general scoring systems to predict outcome in OHCA would be helpful.

Aims

We sought to determine whether the addition of an admission lactate ≥8 mmol/l to the existing CREST score was able to better predict in-hospital mortality in patients admitted with OHCA.

Methods and results

We retrospectively analysed the data of 500 patients admitted with an OHCA of presumed cardiac origin to our tertiary cardiac centre between June 2014 and Oct 2018. Mean age was 62.6y (±14.7), 379 (76%) were male and 250 (50%) were Caucasian. 313 (62.6%) were admitted with ST elevation myocardial infarction or equivalent. 48.6% (243/500) of patients died in hospital and of those that survived, 20.2% (52/257) were left with hypoxic brain injury (CPC score 3–4).

When analysed independently, all individual factors other than history of Coronary artery disease (OR 1.47, p=0.084) significantly predicted in-hospital mortality: Admission lactate ≥8 mmol/l (OR 6.78, p<0.0001), non-shockable Rhythm (OR 10.9, p<0.0001), Ejection fraction <30% (OR 5.84, p<0.0001), Shock at presentation (OR 5.49, p<0.0001) and ischaemic Time >25 minutes (OR 12.8, p<0.0001).

When each factor was assigned one point and totalled, both increasing CREST and C-AREST scores were associated with increasing in-hospital mortality: CREST (0–5 points): 4.3%, 30.5%, 41.5%, 85.6%, 95.2%, 100% vs C-AREST (0–6 points): 9.1%, 28.3%, 41.9%, 62.8%, 97.6%, 96.4%, 100%. When analysed with stepwise logistic regression, the addition of admission lactate ≥8 mmol/l to the model improved the prediction of in-hospital mortality: CREST (40.8% of variance explained) vs C-AREST (43.3%), with admission lactate remaining an independently significant predictor (OR 3.67, p=0.002).

Conclusion

We describe a novel modification to the previously described CREST scoring system for OHCA: the C-AREST score. The addition of admission lactate ≥8 mmol/l may have a role in differentiating those in intermediate risk categories (score between 2 and 3) where the predicted in hospital mortality would otherwise vary greatly. Given the relative ease of obtaining admission lactate, this scoring system may further improve stratification of patients who may or may not benefit from invasive management.

P2665An observational study assessing the impact of a cardiac arrest centre on patient outcome

Background

Out-of-hospital cardiac arrest (OHCA) is a major cause of death in Europe and the United States. There has been recent literature to suggest that the centralisation of OHCA services may benefit patient outcomes. In 2015, two major tertiary cardiac centres in the UK agglomerated to form a large dedicated tertiary cardiac centre. The previous centre had strict criteria on which OHCA patients could be admitted, with the vast majority of cases being STEMI-related. After the agglomeration, admission criteria were relaxed to include all OHCA cases within geographic range with a suspected cardiac cause.

Purpose

This study aimed to compare the short-term mortality of patients admitted with an OHCA to a tertiary cardiac centre before-and-after a major agglomeration of services had taken place and admission criteria had been relaxed.

Methods

We retrospectively analysed the data of patients admitted before and after agglomeration (2015) with OHCA who were resuscitated via conventional cardiopulmonary resuscitation. Baseline demographic characteristics were recorded, along with factors relating to the cardiac arrest. Primary endpoint was in-hospital mortality.

Results

A total of 650 patients (189 before and 461 after the agglomeration) with an OHCA between 2013 and 2018 were analysed. Patients admitted pre merger were older (67.7 vs 62.4 years, p=0.022), otherwise there were similar baseline demographic characteristics between patients admitted before and after the agglomeration (pre vs post) in terms of gender (74.4% vs 75.9% male, p=0.827), ethnicity (66.7% vs 58.9% Caucasian, p=0.588) and existing coronary artery disease (22.8% vs 22.7%, p=0.432). There were also similar peri-arrest characteristics, with a comparable number of patients having a non-shockable rhythm (15.4% vs 25.4%, p=0.164) and similar total downtimes between the groups (33 vs 32.3 mins, p=0.883). Interestingly there was a decrease in those with cardiogenic shock on arrival (92.3% vs 57.0%, p=0.0001) and fewer patients with an ejection fraction <30% (63.2 vs 38.7%, p=0.0003) post-agglomeration.

There was a greater proportion of non-ACS-related OHCA admission after the agglomeration (16.9% vs 24.1%, p=0.047) and a corresponding decrease in those admitted with a STEMI (81.5% vs 62.3%, p=0.032) and those treated with PCI (77.8% vs 54.0%, p=0.034). Despite this, in-hospital mortality was lower after the agglomeration (69.7% vs 47.1%, p=0.019), which persisted after adjustment for the previously described demographic and arrest-related characteristics using stepwise logistic regression (p=0.036) between the two groups.

Conclusion

Despite an increase in non-ACS-related-OHCA cases, the formation of a centralised invasive heart centre was associated with improved survival in OHCA patients. This suggests there may be a benefit for an out-of-hospital cardiac arrest-centre model of care, supporting a centralised strategy for immediate post-resuscitation care in OHCA patients.

Acknowledgement/Funding

None

The impact of weekends on outcome for emergency patients

Levels of staffing and access to diagnostics at weekends are recognised to be significantly lower than on weekdays. It is unclear if subsequent inpatient mortality and readmission rates for acute medical admissions are increased for weekend admissions compared to those on a weekday. A large Canadian study demonstrated increased weekend mortality but does the Edinburgh healthcare model support these findings? This study analysed all hospital admissions in 2001 to the Royal Infirmary of Edinburgh for six predetermined diagnoses (total 3,244): chronic obstructive pulmonary disease, cerebrovascular accidents, pulmonary embolism, pneumonia, collapse and upper gastrointestinal bleed. We compared hospital mortality rates, readmission rates and hospital length of stay for weekend admissions as compared to those on a weekday. Weekend admission was not associated with significantly higher in-hospital mortality, readmission rates or increased length of stay compared to the weekday equivalent for any of the six conditions. The implementation of an acute medical admissions unit in the Royal Infirmary of Edinburgh, with consistent staffing levels and 24-hour access to diagnostics for the early phase of critical illness, may have helped address the discrepancy in care suggested by previous studies.

Characterization of sequence determinants within the carboxyl-terminal domain of chemokine receptor CCR5 that regulate signaling and receptor internalization

The CC chemokine receptor CCR5 mediates chemotaxis of leukocytes and serves as a principal co-receptor for macrophage-tropic human immunodeficiency virus type 1. To identify determinants on the CCR5 carboxyl-terminal domain that regulate receptor signaling and internalization, we generated several CCR5 mutants, which were progressively shortened from the COOH terminus or had carboxyl-terminal serine, cysteine, or leucine residues substituted by alanine and expressed them in RBL-2H3 cells. Using fluorescence resonance energy transfer between beta-arrestin and CCR5 tagged with cyan and yellow variants of green fluorescent protein, we show that high affinity association of the two molecules in living cells requires intact carboxyl-terminal serine phosphorylation sites. Phosphorylation-deficient truncation or Ser/Ala replacement mutants of CCR5 mediated a sustained calcium response and enhanced granular enzyme release in RANTES-stimulated cells. Carboxyl-terminal serine residues are critically involved in CCR5 endocytosis and a dileucine motif, similar to that implicated in the regulation of CXCR2 and CXCR4, contributes to the internalization of CCR5 in a phosphorylation-independent manner. Despite their prominent role in receptor desensitization and internalization, beta-arrestins are dispensable for the CCR5-mediated stimulation of mitogen-activated protein kinase pathways in RBL-2H3 cells. We also show that CCR5 is palmitoylated on carboxyl-terminal cysteine residues. Inhibition of CCR5 palmitoylation by alanine mutagenesis of cysteines or treatment with a palmitate analogue inhibitor profoundly reduces phorbol 12-myristate 13-acetate- and RANTES-induced receptor phosphorylation, homologous desensitization, and internalization. Alanine mutagenesis of serine, cysteine, or leucine residues or the limited carboxyl-terminal truncation of CCR5 did not impair chemokine-stimulated migration of RBL-2H3 cells. Together these results indicate that post-translational modifications of carboxyl-terminal serine and cysteine residues have a significant impact on receptor deactivation and internalization.

Stem cell factor-induced leukotriene B4 production cooperates with eotaxin to mediate the recruitment of eosinophils during allergic pleurisy in mice

The understanding of the mechanisms underlying eosinophil recruitment in vivo may aid in the development of novel strategies for the treatment of allergic disorders. In this study, we investigated the role of chemokines in the cascade of events leading to eosinophil recruitment in a stem cell factor (SCF)- and leukotriene B(4) (LTB(4))-dependent allergic pleurisy model in mice. The intrapleural administration of the eosinophil-active chemokines eotaxin, RANTES, and macrophage-inflammatory protein 1alpha (MIP-1alpha) induced a time- and dose-dependent eosinophil recruitment. Pretreatment with anti-eotaxin, but not anti-RANTES or anti-MIP-1alpha, blocked the recruitment of eosinophils following Ag challenge of sensitized animals, and significant eotaxin immunoreactivity was detected in the pleural cavity of these animals. Similarly, only the anti-eotaxin inhibited the eosinophil recruitment induced by injection of SCF in naive animals. However, blockade of SCF did not inhibit the release of eotaxin after Ag challenge of sensitized mice. Akin to its effects on SCF and in the allergic reaction, eotaxin-induced eosinophil recruitment was blocked by the LTB(4) receptor antagonist CP105696. Nevertheless, SCF, but not eotaxin, appeared to regulate the endogenous release of LTB(4) after Ag challenge. Finally, we show that low doses of eotaxin synergized with LTB(4) to induce eosinophil recruitment in the pleural cavity. Overall, the present results show that eotaxin and SCF-induced LTB(4) cooperate to induce eosinophil recruitment into sites of allergic inflammation. Cooperation between inflammatory mediators must be an important phenomenon in vivo, explaining both the ability of lower concentrations of mediators to induce a full-blown functional response and the effectiveness of different strategies at inhibiting these responses.

Up-regulation of CCR1 and CCR3 and induction of chemotaxis to CC chemokines by IFN-gamma in human neutrophils

Human neutrophils (polymorphonuclear leukocytes; PMN) respond to some CXC chemokines but do not migrate to CC chemokines. Recent work has shown that chemokine receptors can be modulated by inflammatory cytokines. In this study, the effect of IFN-gamma, a prototypic Th1 cytokine, on chemokine receptor expression in PMN was investigated. IFN-gamma caused a rapid (approximately 1 h) and concentration-dependent increase of CCR1 and CCR3 mRNA. The expression of CCR2, CCR5, and CXCR1-4 was not augmented. IFN-gamma-treated PMN, but not control cells, expressed specific binding sites for labeled monocyte-chemotactic protein (MCP)-3 and migrated to macrophage-inflammatory protein (MIP)-1alpha, RANTES, MCP-3, MIP-5/HCC2, and eotaxin. 7B11, a mAb for CCR3, inhibited the chemotactic response of IFN-gamma-treated PMN to eotaxin, and aminoxypentane-RANTES blocked PMN migration to RANTES. These results suggest that the selectivity of certain chemokines for their target cells may be altered by cytokines produced within an inflammatory context. Since PMN may play a role in orienting immunity toward Th1 responses, it is possible to speculate that IFN-gamma not only promotes Th1 differentiation directly, but also reorients the functional significance of Th2 effector cytokines by broadening the spectrum of their action to include PMN.

Role of fimbriae-mediated adherence for neutrophil migration across Escherichia coli-infected epithelial cell layers

This study examined the role of P and type 1 fimbriae for neutrophil migration across Escherichia coli-infected uroepithelial cell layers in vitro and for neutrophil recruitment to the urinary tract in vivo. Recombinant E. coli K-12 strains differing in P or type 1 fimbrial expression were used to infect confluent epithelial layers on the underside of transwell inserts. Neutrophils were added to the upper well, and their passage across the epithelial cell layers was quantified. Infection with the P- and type 1-fimbriated recombinant E. coli strains stimulated neutrophil migration to the same extent as a fully virulent clinical E. coli isolate, but the isogenic non-fimbriated vector control strains had no stimulatory effect. The enhancement of neutrophil migration was adhesion dependent; it was inhibited by soluble receptor analogues blocking the binding of P fimbriae to the globoseries of glycosphingolipids or of type 1 fimbriae to mannosylated glycoprotein receptors. P- and type 1-fimbriated E. coli triggered higher interleukin (IL) 8 secretion and expression of functional IL-8 receptors than non-fimbriated controls, and the increase in neutrophil migration across infected cell layers was inhibited by anti-IL-8 antibodies. In a mouse infection model, P- or type 1-fimbriated E. coli stimulated higher chemokine (MIP-2) and neutrophil responses than the non-fimbriated vector controls. The results demonstrated that transformation with the pap or fim DNA sequences is sufficient to convert an E. coli K-12 strain to a host response inducer, and that fimbriation enhances neutrophil recruitment in vitro and in vivo. Epithelial chemokine production provides a molecular link between the fimbriated bacteria that adhere to epithelial cells and tissue inflammation.

Practical management of the poisoned patient

Clinical toxicology is undergoing a change in its previously perceived unscientific image. As in other medical disciplines, there is an effort to ensure that its treatments are evidence based. A successful outcome seems likely not only to rationalize the management of poisoned patients but to simplify it.

The coordinated action of CC chemokines in the lung orchestrates allergic inflammation and airway hyperresponsiveness

The complex pathophysiology of lung allergic inflammation and bronchial hyperresponsiveness (BHR) that characterize asthma is achieved by the regulated accumulation and activation of different leukocyte subsets in the lung. The development and maintenance of these processes correlate with the coordinated production of chemokines. Here, we have assessed the role that different chemokines play in lung allergic inflammation and BHR by blocking their activities in vivo. Our results show that blockage of each one of these chemokines reduces both lung leukocyte infiltration and BHR in a substantially different way. Thus, eotaxin neutralization reduces specifically BHR and lung eosinophilia transiently after each antigen exposure. Monocyte chemoattractant protein (MCP)-5 neutralization abolishes BHR not by affecting the accumulation of inflammatory leukocytes in the airways, but rather by altering the trafficking of the eosinophils and other leukocytes through the lung interstitium. Neutralization of RANTES (regulated upon activation, normal T cell expressed and secreted) receptor(s) with a receptor antagonist decreases significantly lymphocyte and eosinophil infiltration as well as mRNA expression of eotaxin and RANTES. In contrast, neutralization of one of the ligands for RANTES receptors, macrophage-inflammatory protein 1alpha, reduces only slightly lung eosinophilia and BHR. Finally, MCP-1 neutralization diminishes drastically BHR and inflammation, and this correlates with a pronounced decrease in monocyte- and lymphocyte-derived inflammatory mediators. These results suggest that different chemokines activate different cellular and molecular pathways that in a coordinated fashion contribute to the complex pathophysiology of asthma, and that their individual blockage results in intervention at different levels of these processes.

Role of MCP-1 and RANTES in inflammation and progression to fibrosis during murine crescentic nephritis

The involvement of chemokines in inflammation is well established but their functional role in disease progression, and particularly in the development of fibrosis, is not yet understood. We have investigated the functional role that the chemokines monocyte chemotactic protein-1 (MCP-1) and RANTES play in inflammation and the progression to fibrosis during crescentic nephritis. During this disease inflammatory infiltrates are observed within glomeruli and interstitium in conjunction with increased expression of MCP-1 and RANTES and a decrease in renal function. Disease progression is marked by formation of glomerular crescents and the deposition of type I collagen. Blocking the function of MCP-1 or RANTES resulted in significant decreases in proteinuria as well as numbers of infiltrating leukocytes, indicating that both MCP-1 and RANTES play an important role in the inflammatory phase of crescentic nephritis. In particular, neutralization of MCP-1, but not RANTES, resulted in a dramatic decrease in glomerular crescent formation and deposition of type I collagen. These results highlight a novel role for MCP-1 in crescent formation and development of interstitial fibrosis and indicate that in addition to recruiting inflammatory cells this chemokine is critically involved in irreversible tissue damage.

RANTES and monocyte chemoattractant protein-1 (MCP-1) play an important role in the inflammatory phase of crescentic nephritis, but only MCP-1 is involved in crescent formation and interstitial fibrosis

The involvement of chemokines in inflammation is well established, but their functional role in disease progression, and particularly in the development of fibrosis, is not yet understood. To investigate the functional role that the chemokines monocyte chemoattractant protein-1 (MCP-1) and RANTES play in inflammation and the progression to fibrosis during crescentic nephritis we have developed and characterized a murine model for this syndrome. Significant increases in T-lymphocytes and macrophages were observed within glomeruli and interstitium, paralleled by an induction of mRNA expression of MCP-1 and RANTES, early after disease initiation. Blocking the function of MCP-1 or RANTES resulted in significant decreases in proteinuria as well as in numbers of infiltrating leukocytes, indicating that both MCP-1 and RANTES (regulated upon activation in normal T cells expressed and secreted) play an important role in the inflammatory phase of crescentic nephritis. In addition, neutralization of MCP-1 resulted in a dramatic decrease in both glomerular crescent formation and deposition of type I collagen. These results highlight a novel role for MCP-1 in crescent formation and development of interstitial fibrosis, and indicate that in addition to recruiting inflammatory cells this chemokine is critically involved in irreversible tissue damage.

Cyclic AMP stimulates a JunD/Fra-2 AP-1 complex and inhibits the proliferation of interleukin-6-dependent cell lines

Interleukin-6 (IL-6) is a proinflammatory cytokine which also acts as a growth factor for some murine hybridomas (7TD1) or human myelomas (U266). We demonstrate that elevation of cAMP cellular content inhibits IL-6-stimulated cell growth, by blocking cells mainly in G1 phase. This inhibition is associated with increased expression of the Fos family protein Fra-2. Treatment of cells with 8Br-cAMP results in increased DNA-binding activity of two distinct AP-1 complexes; JunD/Fra-2 and JunB/Fra-2, and also in elevated AP-1 transactivation. When 8Br-cAMP is withdrawn from the medium, cells enter S phase and Fra-2 protein levels and AP-1 DNA-binding activity decrease to their basal value indicating that a temporally correlation exists between the 8Br-cAMP-mediated induction of JunD/Fra-2 AP-1 complex and the 7TD1 and U266 cell growth inhibition.

Granzyme A is an interleukin 1 beta-converting enzyme

Apoptosis is critically dependent on the presence of the ced-3 gene in Caenorhabditis elegans, which encodes a protein homologous to the mammalian interleukin (IL)-1 beta-converting enzyme (ICE). Overexpression of ICE or ced-3 promotes apoptosis. Cytotoxic T lymphocyte-mediated rapid apoptosis is induced by the proteases granzyme A and B. ICE and granzyme B share the rare substrate site of aspartic acid, after which amino acid cleavage of precursor IL-1 beta (pIL-1 beta) occurs. Here we show that granzyme A, but not granzyme B, converts pIL-1 beta to its 17-kD mature form. Major cleavage occurs at Arg120, four amino acids downstream of the authentic processing site, Asp116. IL-1 beta generated by granzyme A is biologically active. When pIL-1 beta processing is monitored in lipopolysaccharide-activated macrophage target cells attacked by cytotoxic T lymphocytes, intracellular conversion precedes lysis. Prior granzyme inactivation blocks this processing. We conclude that the apoptosis-inducing granzyme A and ICE share at least one downstream target substrate, i.e., pIL-1 beta. This suggests that lymphocytes, by means of their own converting enzyme, could initiate a local inflammatory response independent of the presence of ICE.

Two distinct signalling pathways are involved in the control of the biphasic junB transcription induced by interleukin-6 in the B cell hybridoma 7TD1

We have measured the level of junB mRNA in the B hybridoma cell line 7TD1, under interleukin-6 (IL-6) stimulation. IL-6 increases junB mRNA in a biphasic fashion. The first early-induced peak was transient and likely corresponds to the well documented typical junB mRNA, stimulated in response to numerous growth factors, including IL-6. At variance, the second peak which has never been reported previously, lasted several hours. As a consequence of its effect on junB mRNA, IL-6 stimulated, in a biphasic fashion, the nuclear accumulation of the JunB protein. In this study, we demonstrated that IL-6 regulation occurred exclusively at the transcriptional level and that the bimodal increase of junB mRNA and JunB protein can be accounted for by a biphasic stimulation of junB transcription. Furthermore, our data point to two major differences between the mechanism of control of the early and the late IL-6-induced junB transcription waves. First, cycloheximide strongly potentiated the transcription of the second wave, whereas it failed to affect the early-induced burst. Second, tyrphostin, a tyrosine kinase inhibitor, impaired the expression of the first but not the second junB mRNA peak. Conversely, genistein, another tyrosine kinase inhibitor, totally abolished the expression of the second peak of junB mRNA whereas it did not affect the expression of the first peak. Altogether these data indicate that, in 7TD1 cells, IL-6 controls junB transcription in a biphasic fashion by means of two separate transduction pathways.

Inducible inhibition of eukaryotic gene expression

A regulatable binary expression system for eukaryotes was recently developed based on the tetracycline repressor and its operator. Here we show that this system can be successfully applied to express antisense RNA and completely inhibit gene expression in a tetracycline-repressible fashion.

Human interleukin-6: detection of 10 attomoles by colorimetric sandwich ELISA using immunopurified polyclonal anti-IL-6 antibodies

A convenient and sensitive sequential sandwich colorimetric ELISA test was established for quantitating IL-6 in culture supernatants or in serum. Immunopurified HRP-labelled rabbit Fab' fragment was used as the tracer and IgG-coated microtiter plate as the capture antibody. The limit of detection was as low as 10 attomoles of analyte (2.5 pg/ml). Unglycosylated recombinant IL-6 and the natural glycosylated cytokine were recognized equally. In addition, IL-6 measurements were unaffected by the presence of various cytokines and assay sensitivity was only slightly reduced in the presence of undiluted serum samples. The technique was applied to the study of in vitro IL-6 production from activated monocytes and to the in vivo determination of IL-6 in various pathological states.

PMI40, an intron-containing gene required for early steps in yeast mannosylation

We have previously described a temperature-sensitive pmi40-1 mutant of Saccharomyces cerevisiae which is defective in glycosylation and secretion because of a thermolabile phosphomannose isomerase (PMI) activity. Inactivation of PMI at the restrictive temperature of 37 degrees C prevents synthesis of the GDP-mannose and dolichol-phosphate-mannose required for a number of critical mannosyl transfer reactions and results in cell death. Here, we report the isolation of the PMI40 gene by complementation of the corresponding mutation. The PMI40 gene contains an efficiently spliced intron which differs from the majority of those so far identified in S. cerevisiae in that it is short and the branch-forming structure has an AACTAAC motif replacing the highly conserved consensus TACTAAC. The 48.2-kDa protein predicted to be encoded by PMI40 contains amino acid sequences corresponding to those of internal peptides derived from purified S. cerevisiae PMI. Deletion of the PMI40 coding sequence results in a strain requiring D-mannose for growth. The PMI40 gene is located on chromosome V, and its transcription is increased 12-fold when cells are grown on D-mannose as sole carbon source instead of D-glucose. PMI enzyme activity, however, is not increased in D-mannose-grown cells, and PMI protein levels remain constant, suggesting that the PMI40 gene is subject to additional levels of regulation.

In vitro and in vivo studies with purified recombinant human interleukin 5

The functional activities of highly purified recombinant human IL 5 (hIL 5) have been characterized on a number of cell types in vitro and in BALB/c mice in vivo. In vitro, hIL 5 could induce the differentiation of eosinophils from precursors in both human and mouse bone marrow with approximately the same efficiency. A mouse IL 5/3-dependent B cell line, LyH7.B13, was found to proliferate in response to hIL 5 but not human interleukin 1 (IL 1), interleukin 2 (IL 2), interleukin 3 (IL 3), interleukin 4 (IL 4), interleukin 6 (IL 6), interferon-gamma (IFN-gamma), or granulocyte macrophage-colony stimulating factor (GM-CSF) and was at least 10-fold more sensitive than BCL1 mouse lymphoma cells. We have successfully used this cell line to demonstrate the production of IL 5 by human T cell clones. In marked contrast to its effects on murine B cell lines, hIL 5 had no demonstrable activity on CD23 expression, anti-mu costimulated proliferation or IgM, IgG, or IgE production by tonsillar B cells and did not influence such responses triggered by IL 4. BALB/c mice injected with hIL 5 for 7 consecutive days were shown to develop an eosinophilia comparable to that induced by infection with the parasite Mesocestoid corti.

Immunoaffinity fractionation of high-density lipoprotein subclasses 2 and 3 using anti-apolipoprotein A-I and A-II immunosorbent gels

High-density lipoprotein (HDL) subclasses 2 and 3 prepared by density gradient ultracentrifugation have been further fractionated by immunoaffinity chromatography using antibody affinity gels targetting the major HDL apolipoproteins, A-I and A-II. Fractions containing A-I without A-II (AI w/o AII) and A-I with A-II (AI w AII) were isolated from both density ranges. Whereas there were similar concentrations of the major subfraction (HDL3(AI w AII] in both males and females, the remaining subfractions were present in higher concentrations in females as compared to males, in the order HDL3 (AI w/o AII) less than HDL2(AI w AII) less than HDL2(AI w/o AII). The difference was most marked for HDL2 (AI w/o AII), where plasma concentrations in females were almost 3-fold greater than in males. Compositional analyses indicated that the plasma concentrations of the fractions, rather than their compositions, were the major determinants of male-female differences in HDL levels. In contrast, fractions defined by similar apolipoprotein criteria and isolated from different density subclasses (i.e., HDL2(AI w/o AII) vs. HDL3(AI w/o AII) and HDL2(AI w AII) vs. HDL3(AI w AII] showed major compositional differences. This is suggestive of distinct lipoprotein particles.

Edinburgh breast education campaign on breast cancer and breast self-examination: was it worth while?

A health education campaign was carried out at the start of a large trial of screening for breast cancer in Edinburgh. After preliminary studies the campaign concentrated on talks to small groups of women by specially trained health visitors. Over a year, 12,000 women attended. Systematic evaluation after 12 months showed that selected women who heard the talks were more knowledgeable about breast cancer, and a random sample of women in Edinburgh had a small but significant improvement in knowledge compared with women in Aberdeen. However, the random sample did not report an increase in the practice of breast self-examination (BSE) and there was no increase in workload for general practitioners. It is suggested that BSE is more likely to be accepted if combined with a physical examination.

High-performance liquid chromatographic determination of platinum (II) in plasma ultrafiltrate and urine: comparison with a flameless atomic absorption spectrometric method

A technically simple, rapid and sensitive high performance liquid chromatographic assay for cis-dichlorodiammineplatinum (II) in human plasma ultrafiltrate and urine is described. The drug was chelated by exchange with diethyldithiocarbamate and extracted into chloroform. Nickel (II) was used as an internal standard which allows correction for the matrix effects observed with previous chromatographic and spectrometric methods. Chromatography was performed on a mu-Bondapak CN column and the eluent measured spectrophotometrically at 254 nm. Precision and reproducibility were both excellent and the detection limit was less than 50 ng/ml using only 1 ml of biological fluid.