Undertaking multi-centre randomised controlled trials in primary care: learnings and recommendations from the PULsE-AI trial researchers

BACKGROUND

Conducting effective and translational research can be challenging and few trials undertake formal reflection exercises and disseminate learnings from them. Following completion of our multicentre randomised controlled trial, which was impacted by the COVID-19 pandemic, we sought to reflect on our experiences and share our thoughts on challenges, lessons learned, and recommendations for researchers undertaking or considering research in primary care.

METHODS

Researchers involved in the Prediction of Undiagnosed atriaL fibrillation using a machinE learning AlgorIthm (PULsE-AI) trial, conducted in England from June 2019 to February 2021 were invited to participate in a qualitative reflection exercise. Members of the Trial Steering Committee (TSC) were invited to attend a semi-structured focus group session, Principal Investigators and their research teams at practices involved in the trial were invited to participate in a semi-structured interview. Following transcription, reflexive thematic analysis was undertaken based on pre-specified themes of recruitment, challenges, lessons learned, and recommendations that formed the structure of the focus group/interview sessions, whilst also allowing the exploration of new themes that emerged from the data.

RESULTS

Eight of 14 members of the TSC, and one of six practices involved in the trial participated in the reflection exercise. Recruitment was highlighted as a major challenge encountered by trial researchers, even prior to disruption due to the COVID-19 pandemic. Researchers also commented on themes such as the need to consider incentivisation, and challenges associated with using technology in trials, especially in older age groups.

CONCLUSIONS

Undertaking a formal reflection exercise following the completion of the PULsE-AI trial enabled us to review experiences encountered whilst undertaking a prospective randomised trial in primary care. In sharing our learnings, we hope to support other clinicians undertaking research in primary care to ensure that future trials are of optimal value for furthering knowledge, streamlining pathways, and benefitting patients.

Detecting transthyretin amyloid cardiomyopathy (ATTR-CM) using machine learning: an evaluation of the performance of an algorithm in a UK setting

OBJECTIVE

The aim of this study was to evaluate the potential real-world application of a machine learning (ML) algorithm, developed and trained on heart failure (HF) cohorts in the USA, to detect patients with undiagnosed wild type cardiac amyloidosis (ATTRwt) in the UK.

DESIGN

In this retrospective observational study, anonymised, linked primary and secondary care data (Clinical Practice Research Datalink GOLD and Hospital Episode Statistics, respectively, were used to identify patients diagnosed with HF between 2009 and 2018 in the UK. International Classification of Diseases (ICD)-10 clinical modification codes were matched to equivalent Read (primary care) and ICD-10 WHO (secondary care) diagnosis codes used in the UK. In the absence of specific Read or ICD-10 WHO codes for ATTRwt, two proxy case definitions (definitive and possible cases) based on the degree of confidence that the contributing codes defined true ATTRwt cases were created using ML.

PRIMARY OUTCOME MEASURE

Algorithm performance was evaluated primarily using the area under the receiver operating curve (AUROC) by comparing the actual versus algorithm predicted case definitions at varying sensitivities and specificities.

RESULTS

The algorithm demonstrated strongest predictive ability when a combination of primary care and secondary care data were used (AUROC: 0.84 in definitive cohort and 0.86 in possible cohort). For primary care or secondary care data alone, performance ranged from 0.68 to 0.78.

CONCLUSION

The ML algorithm, despite being developed in a US population, was effective at identifying patients that may have ATTRwt in a UK setting. Its potential use in research and clinical care to aid identification of patients with undiagnosed ATTRwt, possibly enabling earlier diagnosis in the disease pathway, should be investigated.

Identification of undiagnosed atrial fibrillation using a machine learning risk-prediction algorithm and diagnostic testing (PULsE-AI) in primary care: a multi-centre randomized controlled trial in England

Aims

The aim of the PULsE-AI trial was to assess the effectiveness of a machine learning risk-prediction algorithm in conjunction with diagnostic testing for identifying undiagnosed atrial fibrillation (AF) in primary care in England.

Methods and results

Eligible participants (aged ≥30 years without AF diagnosis; n = 23 745) from six general practices in England were randomized into intervention and control arms. Intervention arm participants, identified by the algorithm as high risk of undiagnosed AF (n = 944), were invited for diagnostic testing (n = 256 consented); those who did not accept the invitation, and all control arm participants, were managed routinely. The primary endpoint was the proportion of AF, atrial flutter, and fast atrial tachycardia diagnoses during the trial (June 2019-February 2021) in high-risk participants. Atrial fibrillation and related arrhythmias were diagnosed in 5.63% and 4.93% of high-risk participants in intervention and control arms, respectively {odds ratio (OR) [95% confidence interval (CI)]: 1.15 (0.77-1.73), P = 0.486}. Among intervention arm participants who underwent diagnostic testing (28.1%), 9.41% received AF and related arrhythmia diagnoses [vs. 4.93% (control); OR (95% CI): 2.24 (1.31-3.73), P = 0.003].

Conclusion

The AF risk-prediction algorithm accurately identified high-risk participants in both arms. While the proportions of AF and related arrhythmia diagnoses were not significantly different between high-risk arms, intervention arm participants who underwent diagnostic testing were twice as likely to receive arrhythmia diagnoses compared with routine care. The algorithm could be a valuable tool to select primary care groups at high risk of undiagnosed AF who may benefit from diagnostic testing.

Identification of undiagnosed atrial fibrillation using a machine learning risk prediction algorithm and diagnostic testing (PULsE-AI) in primary care: cost-effectiveness of a screening strategy evaluated in a randomized controlled trial in England

OBJECTIVE

The PULsE-AI trial sought to determine the effectiveness of a screening strategy that included a machine learning risk prediction algorithm in conjunction with diagnostic testing for identification of undiagnosed atrial fibrillation (AF) in primary care. This study aimed to evaluate the cost-effectiveness of implementing the screening strategy in a real-world setting.

METHODS

Data from the PULsE-AI trial - a prospective, randomized, controlled trial conducted across six general practices in England from June 2019 to February 2021 - were used to inform a cost-effectiveness analysis that included a hybrid screening decision tree and Markov AF disease progression model. Model outcomes were reported at both individual- and population-level (estimated UK population ≥30 years of age at high-risk of undiagnosed AF) and included number of patients screened, number of AF cases identified, mean total and incremental costs (screening, events, treatment), quality-adjusted-life-years (QALYs), and incremental cost-effectiveness ratio (ICER).

RESULTS

The screening strategy was estimated to result in 45,493 new diagnoses of AF across the high-risk population in the UK (3.3 million), and an estimated additional 14,004 lifetime diagnoses compared with routine care only. Per-patient costs for high-risk individuals who underwent the screening strategy were estimated at £1,985 (vs £1,888 for individuals receiving routine care only). At a population-level, the screening strategy was associated with a cost increase of approximately £322 million and an increase of 81,000 QALYs. The screening strategy demonstrated cost-effectiveness versus routine care only at an accepted ICER threshold of £20,000 per QALY-gained, with an ICER of £3,994/QALY.

CONCLUSIONS

Compared with routine care only, it is cost-effective to target individuals at high risk of undiagnosed AF, through an AF risk prediction algorithm, who should then undergo diagnostic testing. This AF risk prediction algorithm can reduce the number of patients needed to be screened to identify undiagnosed AF, thus alleviating primary care burden.

Costs and Healthcare Resource Use Associated with Risk of Cardiovascular Morbidity in Patients with Chronic Kidney Disease: Evidence from a Systematic Literature Review

Introduction

The management of chronic kidney disease (CKD) costs in excess of $114 billion in the USA and £1.45 billion in the UK annually and is projected to increase alongside the increasing disease prevalence. The aim of this review was to evaluate the risks of cardiovascular (CV) morbidity, CV mortality or all-cause mortality based on KDIGO (Kidney Disease: Improving Global Outcomes) 2012 categorisations and estimate the additional costs and healthcare resource utilisation associated with CV morbidity linked to CKD severity in US and UK settings.

Methods

A systematic literature review was conducted of studies reporting on the risk of CV morbidity, CV mortality or all-cause mortality characterised by CKD severity (published between January 2000 and September 2018). Additional costs and bed days associated with CKD severity in the USA and UK were estimated on the basis of median hazard ratios for CV morbidity risk at each CKD and albuminuria stage.

Results

Twenty-nine studies reported risk of adverse clinical outcomes based on KDIGO categorisations. Compared to stage 1 (or without) CKD, patients with stage 5 CKD and macroalbuminuria experienced a relative risk increase of 11.77–12.46 across all outcomes. Additional costs and bed days associated with stage 5 CKD and macroalbuminuria (versus stage 1 (or without) CKD) per 1000 patient years were US$3.93 million and 803 bed days and £435,000 and 1017 bed days, in the USA and UK, respectively.

Conclusion

Risks of adverse clinical outcomes increase with CKD and albuminuria severity and are associated with substantial additional costs and resource utilisation. Thus, early diagnosis and proactive management of CKD and its complications should be a priority for healthcare providers to alleviate the burden of CV morbidity and its management on healthcare resources.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-020-01607-4.

Study of the ^{26}Al^{m}(d,p)^{27}Al Reaction and the Influence of the ^{26}Al 0^{+} Isomer on the Destruction of ^{26}Al in the Galaxy

The existence of ^{26}Al (t_{1/2}=7.17×10^{5}  yr) in the interstellar medium provides a direct confirmation of ongoing nucleosynthesis in the Galaxy. The presence of a low-lying 0^{+} isomer (^{26}Al^{m}), however, severely complicates the astrophysical calculations. We present for the first time a study of the ^{26}Al^{m}(d,p)^{27}Al reaction using an isomeric ^{26}Al beam. The selectivity of this reaction allowed the study of ℓ=0 transfers to T=1/2, and T=3/2 states in ^{27}Al. Mirror symmetry arguments were then used to constrain the ^{26}Al^{m}(p,γ)^{27}Si reaction rate and provide an experimentally determined upper limit of the rate for the destruction of isomeric ^{26}Al via radiative proton capture reactions, which is expected to dominate the destruction path of ^{26}Al^{m} in asymptotic giant branch stars, classical novae, and core collapse supernovae.

Direct Evidence for Octupole Deformation in ^{146}Ba and the Origin of Large E1 Moment Variations in Reflection-Asymmetric Nuclei

Despite the more than 1 order of magnitude difference between the measured dipole moments in ^{144}Ba and ^{146}Ba, the octupole correlations in ^{146}Ba are found to be as strong as those in ^{144}Ba with a similarly large value of B(E3;3^{-}→0^{+}) determined as 48(+21-29)  W.u. The new results not only establish unambiguously the presence of a region of octupole deformation centered on these neutron-rich Ba isotopes, but also manifest the dependence of the electric dipole moments on the occupancy of different neutron orbitals in nuclei with enhanced octupole strength, as revealed by fully microscopic calculations.

Direct Evidence of Octupole Deformation in Neutron-Rich ^{144}Ba

The neutron-rich nucleus ^{144}Ba (t_{1/2}=11.5  s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers A less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced E1 transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multistep Coulomb excitation of a post-accelerated 650-MeV ^{144}Ba beam on a 1.0-mg/cm^{2} ^{208}Pb target. The measured value of the matrix element, ⟨3_{1}^{-}∥M(E3)∥0_{1}^{+}⟩=0.65(+17/-23) eb^{3/2}, corresponds to a reduced B(E3) transition probability of 48(+25/-34)  W.u. This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation.

EBIS charge breeder for CARIBU

A high-efficiency charge breeder based on an Electron Beam Ion Source (EBIS) is being developed by the ANL Physics Division to increase the intensity and improve the purity of accelerated radioactive ion beams. A wide variety of low-energy neutron-rich ion beams are produced by the Californium Rare Isotope Breeder Upgrade (CARIBU) for the Argonne Tandem Linac Accelerator System (ATLAS). These beams will be charge-bred by an EBIS charge breeder to a charge-to-mass ratio (q/A) ≥ 1/7 and accelerated by ATLAS to energies of about 10 MeV/u. The assembly of the CARIBU EBIS charge breeder except the injection/extraction beam lines has been completed. This summer we started electron beam commissioning of the EBIS. The first results on electron beam extraction, transport from the electron gun to a high power electron collector are presented and discussed.

Development of electron beam ion source charge breeder for rare isotopes at Californium Rare Isotope Breeder Upgrade

Recently, the Californium Rare Isotope Breeder Upgrade (CARIBU) to the Argonne Tandem Linac Accelerator System (ATLAS) was commissioned and became available for production of rare isotopes. Currently, an electron cyclotron resonance ion source is used as a charge breeder for CARIBU beams. To further increase the intensity and improve the purity of neutron-rich ion beams accelerated by ATLAS, we are developing a high-efficiency charge breeder for CARIBU based on an electron beam ion source (EBIS). The CARIBU EBIS charge breeder will utilize the state-of-the-art EBIS technology recently developed at Brookhaven National Laboratory (BNL). The electron beam current density in the CARIBU EBIS trap will be significantly higher than that in existing operational charge-state breeders based on the EBIS concept. The design of the CARIBU EBIS charge breeder is nearly complete. Long-lead components of the EBIS such as a 6-T superconducting solenoid and an electron gun have been ordered with the delivery schedule in the fall of 2011. Measurements of expected breeding efficiency using the BNL Test EBIS have been performed using a Cs(+) surface ionization ion source for external injection in pulsed mode. In these experiments we have achieved ∼70% injection∕extraction efficiency and breeding efficiency into the most abundant charge state of ∼17%.

The gain-of-function G389R variant of the beta1-adrenoceptor does not influence blood pressure or heart rate response to beta-blockade in hypertensive subjects

Mutation scanning of the beta1-adrenoceptor gene has identified a polymorphism, G389R, that markedly affects G-protein coupling of the receptor and resulting cAMP production. We have investigated the effect of this functionally active polymorphism on clinical response to beta-adrenoceptor blockade. Two cohorts of untreated hypertensive patients randomly assigned to a beta1-selective beta-blocker at the start of antihypertensive therapy were studied retrospectively to see if the G389R polymorphism influenced the response in terms of blood pressure and heart rate. The blood pressure and heart rate responses to treatment were assessed 4 weeks later and compared with the G389R genotype, ascertained by PCR/restriction fragment length polymorphism. The falls in blood pressure and heart rate for the first group (n = 92) by genotype were: GG, 20.1 +/- 3.5/13.9 +/- 2.7 mmHg (systolic/diastolic blood pressure), 18.4 +/- 2.2 beats/min; GR, 20.0 +/- 2.2/15.0 +/- 1.3 mmHg, 16.5 +/- 1.5 beats/min; RR, 20.8 +/- 2.3/13.4 +/- 1.1 mmHg, 16.0 +/- 1.4 beats/min. For the second group (n = 55) the corresponding falls were: GG, 17.0 +/- 4.3/11.2 +/- 3.4 mmHg, 12.0 +/- 3.5 beats/min; GR, 16.6 +/- 1.8/14.4 +/- 1.1 mmHg, 13.1 +/- 2.1 beats/min; RR, 18.0 +/- 1.6/13.0 +/- 1.4 mmHg, 14.4 +/- 1.4 beats/min. The G389R genotype also failed to have a significant effect on pretreatment blood pressure or heart rate in either group. These data suggest that, despite clear functional differences between the G389R receptor variants expressed in vitro, the polymorphism does not affect the haemodynamic response of hypertensive subjects to chronic beta1-adrenoceptor blockade.

beta2-adrenoceptor gene polymorphisms and blood pressure variations in East Anglian Caucasians

OBJECTIVE

The amino-terminal polymorphisms, Arg16Gly and Gln27Glu, of the beta2-adrenergic receptor (beta2AR) have been shown to affect regulation of the receptor expression by an agonist in cell culture studies. The Arg16Gly polymorphism has also been recently shown to be associated with essential hypertension. We therefore evaluated whether the amino-terminal polymorphisms of beta2AR are associated with hypertension in a Caucasian population.

SUBJECTS AND METHODS

We performed an association study in 298 hypertensive patients and an equal number of age-matched normotensive controls from the East Anglian region, with blood pressure assessed categorically and quantitatively. We also examined the influence of the amino-terminal polymorphisms on blood pressure response to beta-blockade in 144 of the patients randomly assigned to this class of drug. Genotyping of the Arg16Gly polymorphism was undertaken by a newly designed mismatched polymerase chain reaction (PCR) and digestion with Nde I, whereas the Gln27Glu polymorphism was genotyped by PCR followed by Fnu4H I cleavage.

RESULTS

We found no differences in the genotype or allele frequencies of the beta2AR polymorphisms between hypertensive and normotensive participants. There was also no association between the beta2AR genotypes and variations in either basal blood pressure or the blood pressure response to a beta-blocker.

CONCLUSION

These findings suggest that the amino-terminal polymorphisms of the beta2AR gene are unlikely to constitute major susceptibility for essential hypertension in the East Anglian population.

Association of the G(s)alpha gene with essential hypertension and response to beta-blockade

We examined whether the GNAS1 locus, encoding the G(s) protein alpha-subunit (G(s)alpha), is implicated in the genetic causes of essential hypertension. A common silent polymorphism (ATT-->ATC, Ile(131)) was identified in exon 5 of the G(s)alpha gene by single-strand conformation polymorphism analysis and DNA sequencing. This polymorphism consists of the presence (+) or absence (-) of a restriction site for FokI. Only 1 other rare allele was found in the coding region; the high GC content of the 5' noncoding sequence prevented mutation scanning of the promoter region of the gene. There was a significant difference in frequency of the FokI alleles between 268 white hypertensives (FokI+:FokI-, 51%:49%) and a matched group of 231 control subjects (FokI+:FokI-, 58%:42%) (P=0.02). Multiple regression analysis showed that the FokI genotype was independently related to the level of untreated systolic blood pressure in 294 well-characterized white hypertensives (P=0.01) but not in normotensives. The influence of the FokI allele on blood pressure (BP) response to beta-blockade was examined in 114 of the patients randomly assigned to this class of drug. Significant differences in frequency of the FokI allele were observed in the good responders (FokI+:FokI-, 62.5%:37.5%, n=36) versus the poor responders (FokI+:FokI-, 41.7%:58.3%, n=30) after beta-blocker therapy (P=0.02). In a multiple regression analysis, the G(s)alpha genotype was the only independent predictor of BP response. These results suggest that the GNAS1 locus might carry a functional variant that influences BP variation and response to beta-blockade in essential hypertension.

A silent mutation, C924T (G308G), in the L1CAM gene results in X linked hydrocephalus (HSAS)

The L1 cell adhesion molecule (L1CAM) is a neuronal gene involved in the development of the nervous system. Mutations in L1CAM are known to cause several clinically overlapping X linked mental retardation conditions: X linked hydrocephalus (HSAS), MASA syndrome (mental retardation, aphasia, shuffling gait, adducted thumbs), spastic paraplegia type I (SPG1), and X linked agenesis of the corpus callosum (ACC). In an analysis of a family with HSAS, we identified a C-->T transition (C924T) in exon 8 that was initially thought to have no effect on the protein sequence as the alteration affected the third base of a codon (G308G). Extensive analysis of the other 27 exons showed no other alteration. A review of the sequence surrounding position 924 indicated that the C-->T transition created a potential 5' splice site consensus sequence, which would result in an in frame deletion of 69 bp from exon 8 and 23 amino acids of the L1CAM protein. RT-PCR of the RNA from an affected male fetus and subsequent sequence analysis confirmed the use of the new splice site. This is the first report of a silent nucleotide substitution in L1CAM giving rise to an alteration at the protein level. Furthermore, it shows that as mutation analysis plays an ever more important role in human genetics, the identification of a synonymous base change should not be routinely discounted as a neutral polymorphism.

Neuropeptide regulation of proinflammatory cytokine responses

Severe traumatic injuries and infections are frequently accompanied by life-threatening shock and are associated with increases in the proinflammatory cytokines, particularly tumor necrosis factor alpha (TNF-alpha). The body's first perception of injury is the nociceptive or pain response. This response is induced at the site of injury and is transmitted systemically by sensory neuropeptides, the tachykinins, released from sensory afferent c-fiber neurons. We studied the role of tachykinins in regulating the production of proinflammatory cytokines induced by the administration of bacterial lipopolysaccharide. Destruction of terminal sensory nerve endings before lipopolysaccharide administration abrogates tachykinin synthesis and down-regulates TNF-alpha transcription and secretion. In contrast, the responses of interleukins-1 and -6 are unaffected. Pretreating animals with an antagonist for the substance P-specific NK-1 receptor also down-regulated the TNF-alpha response, whereas blockade of the NK-2 receptor had no effect. These findings indicate that substance P contributes to the induction of those cytokines that are involved in precipitating the shock response.

Inhibition of apoptosis in polymorphonuclear neutrophils from burn patients

Normal human polymorphonuclear neutrophils (PMN) undergo rapid apoptosis during in vitro culture. In contrast, apoptosis is inhibited in PMN from patients with severe burns. This inhibition is not an inherent property of the cells but is caused by thermolabile factors present in the plasma. Endotoxin and the proinflammatory cytokines interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) do not appear to be directly responsible. The ability of burn plasma to inhibit apoptosis was reduced by neutralizing antibodies to human granulocyte macrophage colony-stimulating factor (GM-CSF). GM-CSF levels could not be detected in the burn plasma. However, the incubation of burn-derived or normal leukocyte populations consisting primarily of PMN in burn plasma induced the production of GM-CSF. The results suggest that activation of GM-CSF synthesis by factor(s) in burn plasma may play a role in regulating inflammation by the inhibition of apoptosis.

Translocation. Incidental phenomenon or true pathology?

OBJECTIVE

This study was conducted to determine if reduction of early postburn endotoxemia influences the cytokine cascade, clinical manifestations of sepsis, and mortality rate.

SUMMARY BACKGROUND DATA

Translocational endotoxemia has been demonstrated postburn in animals and humans. Endotoxin is known to induce the cytokine cascade, which leads to the clinical manifestations of sepsis. Whether reduction of postburn endotoxemia could influence the induction of cytokines has not been demonstrated.

METHODS

In a prospective, randomized study, 76 burn patients were given polymyxin intravenously or served as control subjects. Polymyxin B was given intravenously for 1 week postburn in doses designed to neutralize circulating endotoxemia.

RESULTS

In the polymyxin group, there was a statistically significant reduction in the plasma endotoxin concentration. There was, however, no reduction in the sepsis score or the interleukin-6 levels, and no differences in mortality rates were seen between the two groups.

CONCLUSIONS

Early postburn translocational endotoxemia can be treated with anti-endotoxin agents such as polymyxin B. This, however, does not influence the cytokine cascade or the mortality rate. The systemic inflammatory response syndrome is caused by cytokine induction from the injury and is unaffected by a reduction in the plasma endotoxin concentration.

The Baltimore Sepsis Scale: measurement of sepsis in patients with burns using a new scoring system

A new sepsis scale has been developed, and it consists of 13 parameters, each of which is measured daily on a variable point scale. In 41 patients with major burns the Baltimore Sepsis scale correlated well with death or survival, with occurrence of septicemia, and with the level of serum interleukin-6. It did not correlate well with the level of plasma endotoxin or with the type of organism that was grown in blood cultures (gram-positive or gram-negative). We propose that the Baltimore Sepsis Scale would be an accurate and easy scale to use for the measurement of interventions that are aimed at improving the septic state.

Prolonged effect of CGRP in Raynaud's patients: a double-blind randomised comparison with prostacyclin

1. Calcitonin gene related peptide (CGRP) is a potent endogenous vasodilator to which we have previously demonstrated a specific hypersensitivity in skin blood flow in the hands in patients with Raynaud's disease. 2. We have now investigated whether long infusion of CGRP can relieve symptoms of patients with Raynaud's disease using prostacyclin as a control. 3. Six patients were randomised to receive intravenous infusion of either human alpha-CGRP on one occasion, or prostacyclin (PGI2) on another occasion in a double-blind and cross-over design. The dose of each agent was initially titrated up to 8 ng kg-1 min-1 or to a maximum increase in heart rate of 25 beats min-1. 4. In addition to blood pressure, heart rate and skin blood flow measurements, infrared thermography and cold stress challenge was performed before, immediately after infusion and at 3 and 14 days post-infusion. 5. CGRP caused an increase in hand skin blood flow throughout its infusion, whilst PGI2 caused only a short lived increase. The thermographic results showed significant improvement in hand rewarming 3 days after CGRP but not after PGI2. 6. We conclude that 3 h infusion of CGRP was better tolerated than PGI2 and caused objective improvement up to 3 days. CGRP may be an alternative to PGI2 in some patients.

Increased levels of circulating interleukin 6 in burn patients

The serum levels of interleukin 6 (IL-6) were determined in a population of burn patients. In all patients, IL-6 levels were increased over a 3-week interval with peak concentrations reached during the first week after injury. Patients receiving intravenous polymyxin B therapy according to a regimen designed to reduce endotoxemia manifested greatly reduced levels of both circulating endotoxins and IL-6. Certain patients not treated with polymyxin B showed extraordinarily large increases in IL-6 which were associated with lethal or life-threatening clinical complications. Increased IL-6 levels were also associated with decreased percentage of circulating T cells and corresponding increases in B cells. However, IL-6 did not produce any direct inhibitory effects in vitro on T cell representation or function.

A sensitive radioimmunoassay measuring endothelin-like immunoreactivity in human plasma: comparison of levels in patients with essential hypertension and normotensive control subjects

1. A radioimmunoassay has been developed for measuring endothelin-like immunoreactivity in human plasma using an antibody raised against endothelin-1 which also cross-reacts with big endothelin-1 and endothelin-2 but not endothelin-3. 2. The sensitivity of the assay was 1 fmol/tube with inter- and intra-assay coefficients of variation of 13% and 9%, respectively. Cross-reactivity with endothelin-3 and non-endothelin peptides was less than 1%. 3. Endothelin-like immunoreactivity was present in the plasma of hypertensive patients (n = 25) at a concentration of 5.7 +/- 0.5 pmol/l (mean +/- SEM), which was not significantly different from that of age-matched control subjects (5.1 +/- 0.5 pmol/l). At these levels, endothelin-1 is unlikely to function as a circulating hormone. 4. Within the normotensive group, the concentration of endothelin-like immunoreactivity in plasma was positively correlated with mean arterial blood pressure, but in hypertensive patients it showed a significant negative correlation.

Selective suprasensitivity to calcitonin-gene-related peptide in the hands in Raynaud's phenomenon

The effects of intravenous infusion of three vasodilators on skin blood flow were studied in eight patients with Raynaud's phenomenon and eight controls, matched for age and sex, by means of the non-invasive technique of laser doppler flowmetry (LDF). The responses to calcitonin-gene-related peptide (CGRP) were compared with those to the endothelium-dependent vasodilator adenosine triphosphate (ATP) and the endothelium-independent vasodilator prostacyclin (epoprostenol; PGI2). In the patients with Raynaud's phenomenon, CGRP induced flushing of the face and hands accompanied by a rise in skin blood flow, whereas in the controls CGRP caused flushing and increased blood flow only in the face. PGI2 caused similar rises in skin blood flow in the hands and face in both groups. ATP did not cause any significant changes in skin blood flow in the face or hands in the patients, but in the controls it increased skin blood flow in the face. Since the suprasensitivity to CGRP of skin blood flow in the hands of patients with Raynaud's phenomenon is not common to other vasodilators, it may reflect a deficiency of endogenous CGRP release in this disorder.

Nursing care of the infant with erythroblastosis fetalis

Care of the infant with erythroblastosis fetalis is most challenging for the neonatal intensive care nurse. The physiological changes that occur in utero continue to present at birth. The pathology and clinical manifestations, medical treatment, and nursing management of the infant with erythroblastosis fetalis are discussed to assist neonatal intensive care nurses in providing quality care.

Chemical material handling guides

A system has been developed for providing information regarding chemicals, their hazards, and safe handling requirements to employees of Johnson Wax. To initiate the development of a Chemical Material Handling Guide, physical, chemical, and toxicological information is acquired on the chemical raw material, intermediate, or finished product. The guide is prepared by members of a "guides" committee each of whom is responsible for completing one or more of its sections. The five major sections deal with identification, hazard ratings, protective equipment requirements, emergency procedures, and storage, handling and disposal requirements for the chemical material.