Pulmonary thromboembolism in hospitalised patients with COVID-19: a retrospective national study of patients managed in critical care and ward environments in Scotland

OBJECTIVES

To assess for increase in pulmonary thromboembolism (PTE) in hospitalised patients with COVID-19, in both critical care and ward environments.

SETTING

We reviewed all CT pulmonary angiograms (CTPA) performed in Scotland between 23 March 2020 and 31 May 2020 and identified those with COVID-19 using either classical radiological appearances or positive COVID-19 PCR swab.

PARTICIPANTS

All hospitalised patients in Scotland with COVID-19 between 23 March 2020 and 31 May 2020 who underwent a CTPA.

PRIMARY OUTCOME MEASURE

To assess if the rate of PTE was increased in those with COVID-19 compared with previously published figures of hospitalised patients.

SECONDARY OUTCOME MEASURES

To assess the effect of right heart strain or requirement for critical care on mortality.

RESULTS

3401 CTPAs were reviewed. 192 were positive for PTE in patients with evidence of COVID-19 either real-time PCR swab positive for SARS-CoV-2 (n=104) or having radiological changes consistent with COVID-19 (n=88). The total number of hospital admissions in Scotland between 23rd March 2020 and 31st May 2020 with COVID-19 was 5195. The incidence of PTE during this time was 3.7% in all patients admitted to all hospitals in Scotland with COVID-19 during this period. 475 hospitalised patients were managed in critical care (both level 2 and level 3 care), in whom the incidence of PTE was 6% (n=29). 4720 patients did not require admission to critical care, in whom the incidence of PTE was 3.5% (n=163). There was increased risk of death with right heart strain (25/52 vs 128/140 (p<0.01)) and in critical care (15/29 vs 146/163 (p<0.01)).

CONCLUSIONS

We have demonstrated an increased risk of PTE in critical care and ward-based environments. Further studies are required to establish effective prophylactic anticoagulation in this group.

A Context-Dependent Role for the RNF146 Ubiquitin Ligase in Wingless/Wnt Signaling in Drosophila

Aberrant activation of the Wnt signal transduction pathway triggers the development of colorectal cancer. The ADP-ribose polymerase Tankyrase (TNKS) mediates proteolysis of Axin-a negative regulator of Wnt signaling-and provides a promising therapeutic target for Wnt-driven diseases. Proteolysis of TNKS substrates is mediated through their ubiquitination by the poly-ADP-ribose (pADPr)-dependent RING-domain E3 ubiquitin ligase RNF146/Iduna. Like TNKS, RNF146 promotes Axin proteolysis and Wnt pathway activation in some cultured cell lines, but in contrast with TNKS, RNF146 is dispensable for Axin degradation in colorectal carcinoma cells. Thus, the contexts in which RNF146 is essential for TNKS-mediated Axin destabilization and Wnt signaling remain uncertain. Herein, we tested the requirement for RNF146 in TNKS-mediated Axin proteolysis and Wnt pathway activation in a range of in vivo settings. Using null mutants in Drosophila, we provide genetic and biochemical evidence that Rnf146 and Tnks function in the same proteolysis pathway in vivo Furthermore, like Tnks, Drosophila Rnf146 promotes Wingless signaling in multiple developmental contexts by buffering Axin levels to ensure they remain below the threshold at which Wingless signaling is inhibited. However, in contrast with Tnks, Rnf146 is dispensable for Wingless target gene activation and the Wingless-dependent control of intestinal stem cell proliferation in the adult midgut during homeostasis. Together, these findings demonstrate that the requirement for Rnf146 in Tnks-mediated Axin proteolysis and Wingless pathway activation is dependent on physiological context, and suggest that, in some cell types, functionally redundant pADPr-dependent E3 ligases or other compensatory mechanisms promote the Tnks-dependent proteolysis of Axin in both mammalian and Drosophila cells.

Activity of the hypoxia-activated prodrug, TH-302, in preclinical human acute myeloid leukemia models

PURPOSE

Acute myeloid leukemia (AML) is an aggressive hematologic neoplasm. Recent evidence has shown the bone marrow microenvironment in patients with AML to be intrinsically hypoxic. Adaptive cellular responses by leukemia cells to survive under low oxygenation also confer chemoresistance. We therefore asked whether therapeutic exploitation of marrow hypoxia via the hypoxia-activated nitrogen mustard prodrug, TH-302, could effectively inhibit AML growth.

EXPERIMENTAL DESIGN

We assessed the effects of hypoxia and TH-302 on human AML cells, primary samples, and systemic xenograft models.

RESULTS

We observed that human AML cells and primary AML colonies cultured under chronic hypoxia (1% O2, 72 hours) exhibited reduced sensitivity to cytarabine-induced apoptosis as compared with normoxic controls. TH-302 treatment resulted in dose- and hypoxia-dependent apoptosis and cell death in diverse AML cells. TH-302 preferentially decreased proliferation, reduced HIF-1α expression, induced cell-cycle arrest, and enhanced double-stranded DNA breaks in hypoxic AML cells. Hypoxia-induced reactive oxygen species by AML cells were also diminished. In systemic human AML xenografts (HEL, HL60), TH-302 [50 mg/kg intraperitoneally (i.p.) 5 times per week] inhibited disease progression and prolonged overall survival. TH-302 treatment reduced the number of hypoxic cells within leukemic bone marrows and was not associated with hematologic toxicities in nonleukemic or leukemic mice. Later initiation of TH-302 treatment in advanced AML disease was as effective as earlier TH-302 treatment in xenograft models.

CONCLUSIONS

Our results establish the preclinical activity of TH-302 in AML and provide the rationale for further clinical studies of this and other hypoxia-activated agents for leukemia therapy.

MEM: Mechanisms of Recollection

Abstract The MEM framework (Johnson, 1991a, b; Johnson & Hirst, 1992; Johnson & Multhaup, 1992) consists of a relatively small set of component cognitive processes configured into memory subsystems. Here MEM is used to discuss "recollection," particularly the mechanisms by which aspects of experience become bound together to yield the phenomenal experience of contextually specific, event-like memories. I consider how central aspects of complex events are bound to each other and propose that these same cognitive activities operate to bind central and contextual elements into "episodic" memories. Attention is particularly focused on the role of reactivation in establishing complex memories and in strengthening or consolidating them over time.

Hypoxaemia in patients with pulmonary arterial hypertension during simulated air travel

BACKGROUND

Recent air travel recommendations suggest patients with precapillary pulmonary hypertension (PCPH) in New York Heart Association (NYHA) functional class 3 and 4 should have in-flight oxygen without the need for pre-flight testing. However it remains unclear as to how best to determine patients fitness to fly.

METHODS

This study (i) investigates the effect of hypoxic challenge testing (HCT) on the arterial oxygen levels in a cohort of 36 patients with PCPH and (ii) compares the relative frequency with which FC and HCT predict the requirement for in-flight oxygen.

RESULTS

The degree of arterial hypoxaemia induced by HCT (fall in partial pressure of oxygen in arterial blood (PaO(2)) 2.36 kPa, 95% CI 2.06-2.66 kPa) was similar to the drop observed in other published studies of chronic respiratory diseases. Following current air travel recommendations based on FC, 25 patients of the cohort would require in-flight oxygen whilst 10 subjects failed the HCT. Fourteen subjects had flown post-diagnosis. Of these, nine subjects should have had in-flight oxygen based on FC but were asymptomatic without. Also one who passed the HCT had developed symptoms during the flight whilst three who failed the HCT were asymptomatic flying without in-flight oxygen.

CONCLUSIONS

Hypoxaemia induced by simulated air travel in patients with PCPH is similar to that seen in published studies of patients with other chronic respiratory diseases. HCT failed to predict correctly who had developed symptoms during an aircraft flight in a significant minority of the study subjects. Similarly guidelines based on functional class result in a major increase in the proportion of patients being advised to use oxygen, many of whom had been asymptomatic on previous flights without it. More work is required to improve prediction of need for in-flight oxygen in patients with PCPH.

Importance and Timing of End-of-Life Care Discussions Among Gynecologic Oncology Patients

Objectives:

To assess the importance and desired timing of end-of-life care (EOLC) discussions among women with gynecologic cancer.

Methods:

A questionnaire related to EOLC issues was distributed to patients with gynecologic cancer. Answers were analyzed via SPSS using descriptive statistics. Contingency analysis was done to evaluate for differences among disease status and age regarding preferences for timing of discussions.

Results:

Patients expressed that addressing EOLC is an important part of their treatment. Most patients were familiar with advanced directives (73.0%), do not resuscitate/do not intubate (88.5%), and hospice (97.5%). Designating someone to make decisions was significantly related to disease status ( P = .03) and age ( P = 0.02).

Conclusions:

Patients are familiar with basic EOLC with optimal timing for discussions at disease progression or when treatment is no longer available.

Configuration of the setal fields of Rhoptropus (Gekkota: Gekkonidae): functional, evolutionary, ecological and phylogenetic implications of observed pattern

Many gekkotans possess seta-bearing adhesive subdigital pads. Details of setal structure, however, are largely based upon putatively exemplary fibrils deemed typical of the species. Little is known of the pattern of configuration of the setae across the subdigital pads and how great, if any, the variance in structure and dimensions is. To understand setal fields as functional entities, as opposed to individual setae, it is necessary to consider this pattern. Additionally, gekkotans within individual radiations occupy different environments and potentially are substrate-specific in terms of the locomotor surface exploited. To investigate these issues, we herein examine the configuration and dimensions of seven species of the gekkotan genus Rhoptropus, and an outgroup taxon, Chondrodactylus bibronii. All of these taxa are rupicolous and the array of rock surfaces exploited by this cluster of taxa is extensive. Our results show that setal field configuration follows a predictable pattern, both from one digit to another within a species, and between homologous digits and anatomical locations between species. One species, Rhoptropus afer, a more terrestrial taxon, exhibits significantly shorter setae and a smaller subdigital pad area than do its congeners, but exhibits the same overall pattern of setal arrangement. Our findings have implications for the understanding of the evolution of adhesive structures, and for the principles used for generating and manufacturing biomimetic artificial microfibrillar arrays.

Priming Christian Religious Concepts Increases Racial Prejudice

Positive correlations have been found between several self-report measures of religiousness and racial prejudice; however, no experiment has yet examined the direct effect of religion on racial attitudes. In the current studies, persons were subliminally primed with Christian or neutral words. Then covert racial prejudice (Study 1) and general negative affect toward African-Americans (Study 2) were assessed. Participants subliminally primed with Christian words displayed more covert racial prejudice against African-Americans (Study 1) and more general negative affect toward African-Americans (Study 2) than did persons primed with neutral words. The effects of priming on racial prejudice remained even when statistically controlling for pre-existing levels of religiousness and spirituality. Possible mechanisms for the observed effect of Christian religion on racial prejudice are discussed.

Delayed neurotoxicity - do trichlorphon and/or dichlorvos cause delayed neuropathy in man or in test animals?

Many, but not all, reports of delayed neuropathy associated with acute poisoning by trichlorphon refer to cases in U.S.S.R. Adulteration of technical trichlorphon with the ethyl analogue would greatly increase the neurotoxic hazard but analysis of a few samples has not revealed such impurities. Simultaneous ingestion of alcohol does not appear to increase neuropathic hazard. In hens double doses of trichlorphon each exceeding unprotected LD50 can produce moderate neuropathy associated with appropriately high inhibitions of neurotoxic esterase. Similar results are obtained with 2 doses of 10 x LD50 of dichlorvos. In vitro the inhibitory power of dichlorvos against neurotoxic esterase of hen brain is 0.02 x the power against acetylcholinesterase. This ratio correlates reasonably with the ratio of LD50/neuropathic dose. The factor for human brain enzymes is 0.06 suggesting that man is more susceptible to neuropathic effects of near-lethal doses of circulating dichlorvos. It is concluded that the only neuropathic hazard to man from good quality trichlorphon arises from rapid ingestion of massive doses. To obtain critical levels of inhibition of neurotoxic esterase and to cause neuropathy in man by repeated doses would require each dose to be severely toxic. Dichlorvos ingested in large doses is likely to kill rather than to cause neuropathy.

Identification of novel candidate genes associated with cleft lip and palate using array comparative genomic hybridisation

AIM AND METHOD

We analysed DNA samples isolated from individuals born with cleft lip and cleft palate to identify deletions and duplications of candidate gene loci using array comparative genomic hybridisation (array-CGH).

RESULTS

Of 83 syndromic cases analysed we identified one subject with a previously unknown 2.7 Mb deletion at 22q11.21 coinciding with the DiGeorge syndrome region. Eighteen of the syndromic cases had clinical features of Van der Woude syndrome and deletions were identified in five of these, all of which encompassed the interferon regulatory factor 6 (IRF6) gene. In a series of 104 non-syndromic cases we found one subject with a 3.2 Mb deletion at chromosome 6q25.1-25.2 and another with a 2.2 Mb deletion at 10q26.11-26.13. Analyses of parental DNA demonstrated that the two deletion cases at 22q11.21 and 6q25.1-25.2 were de novo, while the deletion of 10q26.11-26.13 was inherited from the mother, who also has a cleft lip. These deletions appear likely to be causally associated with the phenotypes of the subjects. Estrogen receptor 1 (ESR1) and fibroblast growth factor receptor 2 (FGFR2) genes from the 6q25.1-25.2 and 10q26.11-26.13, respectively, were identified as likely causative genes using a gene prioritization software.

CONCLUSION

We have shown that array-CGH analysis of DNA samples derived from cleft lip and palate subjects is an efficient and productive method for identifying candidate chromosomal loci and genes, complementing traditional genetic mapping strategies.

Regulation of iNOS by the p44/42 mitogen-activated protein kinase pathway in human melanoma

Activating mutations of the genes for NRAS and BRAF, components of the p44/42 mitogen-activated protein kinase (MAPK) pathway, are common findings in melanoma. Recent evidence in several nonmelanoma cell systems supports the regulation of the inducible nitric oxide synthase (iNOS) gene by this pathway. On the basis of our data showing that melanoma iNOS expression predicts shortened patient survival, we formulated the hypothesis that activating mutations of NRAS or BRAF, which lead to constitutive activation of the p44/42 MAPK pathway, drive iNOS expression in human melanoma. In the present study, we have shown that inhibition of melanoma iNOS activity by S-methylisothiourea leads to decreased cell proliferation, confirming the importance of iNOS activity for melanoma cell growth. Regulation of melanoma iNOS expression by the p44/42 MAPK pathway was demonstrated by inhibition of the pathway by U0126, and by BRAF RNA interference. To explore this regulatory pathway in human tissue, 20 melanoma tumors were examined for NRAS and BRAF mutations, immunohistochemical evidence of ERK phosphorylation, and iNOS expression. A significant association was found among these three features. We conclude that in human melanoma, activating mutations of NRAS and BRAF drive constitutive iNOS expression and, implicitly, nitric oxide production, contributing to the poor survival of these patients.

Locomotor morphometry of the Pachydactylus radiation of lizards (Gekkota: Gekkonidae): a phylogenetically and ecologically informed analysis

The Pachydactylus radiation comprises a diverse group of African gekkonids that exploit a variety of microhabitats and exhibit both climbing and terrestrial locomotion. The phylogeny of this radiation is well supported, making it a promising candidate for the investigation of relationships between limb proportions, ecology, and behaviour. Skeletal and external measurements were recorded for an array of taxa and analyzed using principal components analysis (PCA). The results of the PCAs were further analyzed using phylogenetic statistical methods to ascertain whether climbing and terrestrial species and (or) clades within the radiation differed significantly from each other in limb proportions. Phylogenetically based comparisons revealed that although there is some differentiation between climbing and terrestrial species, this is not a general pattern but is primarily attributable to certain species and clades within the radiation that differ considerably from other members of the group. The results indicate that Chondrodactylus angulifer Peters, 1870 possesses shortened distal phalanges and that Pachydactylus rangei (Andersson, 1908), P. austeni Hewitt, 1923, and the Rhoptropus clade (particularly R. afer Peters, 1869) possess elongated limbs relative to the rest of the radiation. These differences correlate with aspects of the lifestyles of these species, such as increased terrestriality, a reduction or loss of the subdigital adhesive apparatus, digging behaviour, and a transition to diurnality.

Long-term continuous positive airway pressure (CPAP) outcomes from a sleep service using limited sleep studies and daycase CPAP titration in the management of obstructive sleep apnoea/hypopnoea syndrome

BACKGROUND

Detailed polysomnography (PSG) and overnight continuous positive airway pressure (CPAP) titration as the basis for investigation and treatment of obstructive sleep apnoea/hypopnoea syndrome (OSAHS) incurs high costs from inpatient stays and technician attendance, even when split night studies are employed. Responding to rapidly increasing demand, from 1996 the sleep service at Glasgow Royal Infirmary adopted limited sleep studies and daycase CPAP titration as first line management. Here we describe the outcomes of this service between 1996 and 1999.

METHODS

Data were collected from prospective records made at follow up by sleep technicians and by casenote review.

RESULTS

Results were available for 158 subjects (97.5%) of 162 commenced on CPAP during this period. One hundred and forty-eight (91%) were diagnosed by limited sleep studies and 80 (50%) were diagnosed at home. The median follow up was 23 months (interquartile range (IQR), 13-35). Median use of CPAP in those continuing therapy was 5.3 hours/night (IQR, 3.1 to 6.5) and 77% were still using CPAP at three years. Only initial low CPAP compliance (< 2 hours/night) significantly predicted early CPAP cessation. In those still on CPAP in 1999, the mean drop in Epworth Sleepiness Scale score was 4.6 points (95% confidence intervals, 3.2 to 6.0).

CONCLUSION

These data from the CPAP population at Glasgow Royal Infirmary provide information on longterm outcomes using a diagnostic protocol based on limited sleep studies and daycase CPAP titration.

Use of reactance to estimate transpulmonary resistance

This study examines the relationship of respiratory system resistance (R(rs)) and reactance (X(rs)) measured by forced oscillometry with transpulmonary resistance (R(L)) measured by oesophageal manometry. Simultaneous forced oscillometry using a single frequency of 5 Hz and oesophageal manometry were performed on five asthmatics during bronchoprovocation. The data obtained were used to derive prediction equations for R(L) from oscillometric parameters, which were tested on a further six asthmatics and 35 nonasthmatic subjects. In the first five asthmatic subjects, R(L) correlated more strongly with X(rs) than with R(rs). In the second set of asthmatics, R(L) ranged 0.0005-4.57 kPa.s.L(-1), with a median of 0.21 kPa.s.L(-1). The R(L) values predicted from X(rs) showed a mean+/-sd difference of -0.067+/-0.25 kPa.s.L(-1) compared with the values measured in this set of patients. X(rs) in subjects with other respiratory conditions appeared to follow the same relationship with R(L) as in asthmatics. Lumped element modelling suggested that the linear relationship between X(rs) and R(L) was a consequence of the increasing contribution of central and upper airway wall shunts as peripheral airway resistance rose, and that this effect was much larger than that due to changes in static elastance. In conclusion, the reactance of the respiratory system can predict transpulmonary resistance more accurately than can the resistance of the respiratory system.

Collaborative practice: a successful model

Recognizing the need for better collaboration, nursing personnel from two nonrelated health care facilities, acute care and rehabilitation hospitals, came together to establish a methodology to improve outcomes for patients with spinal cord injury (SCI). Focus areas were to facilitate communication and transition between hospitals. A collaborative practice model evolved for the patient with tetraplegia who is ventilator-dependent. This model has been successfully instituted in both institutions. This article describes the processes used in developing this model. It also includes recommendations for the reader to create a workable process in his or her respective institution.

IscA, an alternate scaffold for Fe-S cluster biosynthesis

An IscA homologue within the nif regulon of Azotobacter vinelandii, designated (Nif)IscA, was expressed in Escherichia coli and purified to homogeneity. Purified (Nif)IscA was found to be a homodimer of 11-kDa subunits that contained no metal centers or other prosthetic groups in its as-isolated form. Possible roles for (Nif)IscA in Fe-S cluster biosynthesis were assessed by investigating the ability to bind iron and to assemble Fe-S clusters in a NifS-directed process, as monitored by the combination of UV-vis absorption, Mössbauer, resonance Raman, variable-temperature magnetic circular dichroism, and EPR spectroscopies. Although (Nif)IscA was found to bind ferrous ion in a tetrahedral, predominantly cysteinyl-ligated coordination environment, the low-binding affinity argues against a specific role as a metallochaperone for the delivery of ferrous ion to other Fe-S cluster assembly proteins. Rather, a role for (Nif)IscA as an alternate scaffold protein for Fe-S cluster biosynthesis is proposed, based on the NifS-directed assembly of approximately one labile [4Fe-4S](2+) cluster per (Nif)IscA homodimer, via a transient [2Fe-2S](2+) cluster intermediate. The cluster assembly process was monitored temporally using UV-vis absorption and Mössbauer spectroscopy, and the intermediate [2Fe-2S](2+)-containing species was additionally characterized by resonance Raman spectroscopy. The Mössbauer and resonance Raman properties of the [2Fe-2S](2+) center are consistent with complete cysteinyl ligation. The presence of three conserved cysteine residues in all IscA proteins and the observed cluster stoichiometry of approximately one [2Fe-2S](2+) or one [4Fe-4S](2+) per homodimer suggest that both cluster types are subunit bridging. In addition, (Nif)IscA was shown to couple delivery of iron and sulfur by using ferrous ion to reduce sulfane sulfur. The ability of Fe-S scaffold proteins to couple the delivery of these two toxic and reactive Fe-S cluster precursors is likely to be important for minimizing the cellular concentrations of free ferrous and sulfide ions. On the basis of the spectroscopic and analytical results, mechanistic schemes for NifS-directed cluster assembly on (Nif)IscA are proposed. It is proposed that the IscA family of proteins provide alternative scaffolds to the NifU and IscU proteins for mediating nif-specific and general Fe-S cluster assembly.

Source ROCs are (typically) curvilinear: comment on Yonelinas (1999)

On the basis of his assumption that recollection is a threshold process, A. P. Yonelinas (1999) predicted linear source-identification receiver operating characteristics (ROCs) and recently reported data that were consistent with this prediction. In this article, the authors present data showing curvilinear source-identification ROCs across various encoding and test conditions. On the basis of the source-monitoring framework (e.g., M. K. Johnson, S. Hashtroudi, & D. S. Lindsay, 1993), the authors argue that curvilinearity of source-identification ROCs is a result of differences in the qualitative characteristics of memories rather than simply the influence of undifferentiated familiarity as the dual-process model might suggest.

A paramagnetic species with unique EPR characteristics in the active site of heterodisulfide reductase from methanogenic archaea

Heterodisulfide reductase (Hdr) from methanogenic archaea is an iron-sulfur protein that catalyses the reversible reduction of the heterodisulfide (CoM-S-S-CoB) of the methanogenic thiol coenzymes, coenzyme M (H-S-CoM) and coenzyme B (H-S-CoB). In EPR spectroscopic studies with the enzyme from Methanothermobacter marburgensis, we have identified a unique paramagnetic species that is formed upon reaction of the oxidized enzyme with H-S-CoM in the absence of H-S-CoB. This paramagnetic species can be reduced in a one-electron step with a midpoint-potential of -185 mV but not further oxidized. A broadening of the EPR signal in the 57Fe-enriched enzyme indicates that it is at least partially iron based. The g values (gxyz = 2.013, 1.991 and 1.938) and the midpoint potential argue against a conventional [2Fe-2S]+, [3Fe-4S]+, [4Fe-4S]+ or [4Fe-4S]3+ cluster. This species reacts with H-S-CoB to form an EPR silent form. Hence, we propose that only a half reaction is catalysed in the presence of H-S-CoM and that a reaction intermediate is trapped. This reaction intermediate is thought to be a [4Fe-4S]3+ cluster that is coordinated by one of the cysteines of a nearby active-site disulfide or by the sulfur of H-S-CoM. A paramagnetic species with similar EPR properties was also identified in Hdr from Methanosarcina barkeri.

Hospital at home services for acute exacerbation of chronic obstructive pulmonary disease: a survey of British practice

OBJECTIVES

To identify the prevalence of and attitudes towards hospital at home services for acute exacerbation of chronic obstructive pulmonary disease (COPD) in Great Britain. To identify the models of service in existence, in particular staff numbers and the workload experienced.

DESIGN

A postal survey was used to locate existing schemes. Telephone interviews were conducted with each of the hospital at home services identified.

SUBJECTS & SETTING

A questionnaire was sent to one consultant in each of 223 respiratory departments in Great Britain. Thirty six departments were subsequently contacted by telephone.

OUTCOME MEASURES

Awareness and prevalence of hospital at home services. Perceived problems with starting a service. Details of organisation of existing services.

RESULTS

We received 186 replies to the postal questionnaire. Of these respiratory departments, 179 (96%) were aware of hospital at home services for acute exacerbation of COPD and, in November 1999, 30 (16%) were running such a service. Difficulty in obtaining funding was the main reason for not setting up a service rather than lack of evidence of benefit or unsuitability of local circumstances. Median staffing level was two nurses (range one to six) looking after a median number of new patients of five per week (range 0.5 to 12). There was wide variation in the organisation of services.

CONCLUSIONS

Despite lack of objective evidence of effectiveness, there was a high level of awareness of and interest in starting hospital at home services for acute exacerbation of COPD in British respiratory departments when assessed in November 1999.

Choice-supportive source monitoring: do our decisions seem better to us as we age?

Participants were given several 2-option choices and then asked to review how they felt about their decisions, to review the details of their decisions, or to do an unrelated task. When later asked to attribute features to the previous options, in each condition older adults (64-83 years) attributed significantly more positive and fewer negative features to their chosen options than to foregone options. Younger adults' (18-22 years) attributions were as choice-supportive as those of older adults in the affective review condition but were less so in the other conditions. The age difference was present even when older and younger adults were equated for source identification and recognition accuracy. This study suggests that as people age, their tendency to distort memory in favor of the options they chose increases. In addition, it suggests that affectively reviewing choices increases younger adults' tendency toward choice-supportive memory.

Brain potentials reflect behavioral differences in true and false recognition

People often falsely recognize nonstudied lures that are semantically similar to previously studied words. Behavioral research suggests that such false recognition is based on high semantic overlap between studied items and lures that yield a feeling of familiarity, whereas true recognition is more often associated with the recollection of details. Despite this behavioral evidence for differences between true and false recognition, research measuring brain activity (PET, fMRI, ERP) has not clearly differentiated corresponding differences in brain activity. A median split was used to separate subjects into Good and Poor performers based on their discrimination of studied targets from similar lures. Only Good performers showed late (1000--1500 msec), right frontal event-related brain potentials (ERPs) that were more positive for targets and lures compared with new items. The right frontal differences are interpreted as reflecting postretrieval evaluation processes that were more likely to be engaged by Good than Poor performers. Both Good and Poor performers showed a parietal ERP old/new effect (400--800 msec), but only Poor performers showed a parietal old/lure difference. These results are consistent with the view that the parietal and frontal ERP old/new effects reflect dissociable processes related to recollection.

Characterization of the NifU and NifS Fe-S cluster formation proteins essential for viability in Helicobacter pylori

The Fe-S cluster formation proteins NifU and NifS are essential for viability in the ulcer causing human pathogen Helicobacter pylori. Obtaining viable H. pylori mutants upon mutagenesis of the genes encoding NifU and NifS was unsuccessful even by growing the potential transformants under many different conditions including low O(2) atmosphere and supplementation with both ferric and ferrous iron. When a second copy of nifU was introduced into the chromosome at a unrelated site, creating a mero-diploid strain for nifU, this second copy of the gene could be disrupted at high frequency. This indicates that the procedures used for transformation were capable of nifU mutagenesis, so that the failure to recover mutants is solely due to the requirement of nifU for H. pylori viability. H. pylori NifU and NifS were expressed in Escherichia coli and purified to near homogeneity, and the proteins were characterized. Purified NifU is a red protein that contains approximately 1.5 atoms of iron per monomer. This iron was determined to be in the form of a redox-active [2Fe-2S](2+,+) cluster by characteristic UV-visible, EPR, and MCD spectra. The primary structure of NifU also contains the three conserved cysteine residues which are involved in providing the scaffold for the assembly of a transient Fe-S cluster for insertion into apoprotein. Purified NifS has a yellow color and UV-visible spectra characteristic of a pyridoxal phosphate containing enzyme. NifS is a cysteine desulfurase, releasing sulfur or sulfide (depending on the reducing environment) from L-cysteine, in agreement with its proposed role as a sulfur donor to Fe-S clusters. The results here indicate that the NifU type of Fe-S cluster formation proteins is not specific for maturation of the nitrogenase proteins and, as H. pylori lacks other Fe-S cluster assembly proteins, that the H. pylori NifS and NifU are responsible for the assembly of many (non-nitrogenase) Fe-S clusters.

Liquidity-related plan asset issues

By about 2025, most baby boomers will have retired, which will put a tremendous strain on public sector pension plans. Many will experience negative cash flows, and liquidity will be an increasing concern. Asset/liability studies can help measure the effect of this risk on system funding and contribution requirements, resulting in more informed asset allocation choices and benefit policies.

Choice-supportive source monitoring: do our decisions seem better to us as we age?

Participants were given several 2-option choices and then asked to review how they felt about their decisions, to review the details of their decisions, or to do an unrelated task. When later asked to attribute features to the previous options, in each condition older adults (64-83 years) attributed significantly more positive and fewer negative features to their chosen options than to foregone options. Younger adults' (18-22 years) attributions were as choice-supportive as those of older adults in the affective review condition but were less so in the other conditions. The age difference was present even when older and younger adults were equated for source identification and recognition accuracy. This study suggests that as people age, their tendency to distort memory in favor of the options they chose increases. In addition, it suggests that affectively reviewing choices increases younger adults' tendency toward choice-supportive memory.

Left anterior prefrontal activation increases with demands to recall specific perceptual information

Results from neuroimaging studies have led to competing theories regarding the contributions of prefrontal regions to memory formation and retrieval. To investigate this issue, we used event-related functional magnetic resonance imaging to assess prefrontal activation during encoding and retrieval of pictures of objects. Responses to studied and unstudied objects at retrieval were compared between two tests with differing demands for the specificity of information to be retrieved (source vs old-new recognition). Results showed that bilateral ventral [Brodmann's areas (BA) 44, 45, and 47] and right dorsal (BA 9) prefrontal regions were activated during both encoding and retrieval, but activity in these regions was not reliably modulated by the specificity of information to be retrieved. A region in left anterior prefrontal cortex (BA 10/46) was reliably activated during retrieval trials, and activation in this region increased with demands to retrieve perceptually detailed information about studied objects. Our results show that left anterior prefrontal cortex is engaged during the monitoring and evaluation of specific memory characteristics at retrieval-a process critical for accurate episodic remembering.

Early discharge for patients with exacerbations of chronic obstructive pulmonary disease: a randomized controlled trial

BACKGROUND

We have previously reported the use of a hospital based respiratory nurse service (Acute Respiratory Assessment Service, ARAS) to support home treatment of patients with exacerbations of chronic obstructive pulmonary disease (COPD). A controlled trial was undertaken to compare early discharge with home treatment supported by respiratory nurses with conventional hospital management of patients admitted with exacerbations of COPD.

METHODS

Patients with COPD admitted as emergencies were identified the next working day. They were eligible for inclusion in the study if the differential diagnosis included an exacerbation of COPD, but were excluded if other medical conditions or acidotic respiratory failure required inpatient investigation or management. Of 360 patients reviewed, 209 were being assessed for other active medical problems and were excluded, 33 potential participants were already involved in research studies and so were ineligible, and 37 did not wish to participate in the study. Eighty one patients were randomised to receive conventional inpatient care (n=40) or to planned early discharge the next working day (n=41). Those discharged early continued treatment at home under the supervision of specialist respiratory nurses. Outcome measures were readmission, additional hospital days, and deaths within 60 days of initial admission. Process measures included number of visits, duration of follow up by the respiratory nurse, and additional treatment provided to support early discharge.

RESULTS

On an intention to treat basis, a policy of early discharge reduced inpatient stay from a mean of 6.1 (range 1-13) days with conventional management to 3.2 (1-16) days with an early discharge policy. Twelve patients (30% conventional management, 29.3% early discharge) were readmitted in each group giving a mean difference in readmission of 0.7% (95% CI of the difference -19.2 to 20.6). In the conventional management group readmitted patients spent a mean of 8.75 additional days in hospital compared with 7.83 days in the early discharge group, giving a mean difference of 0.92 days (95% CI of the difference -6.5 to 8.3). There were two deaths (5%) in the conventional management group and one (2.4%) in the early discharge group, a mean difference of 2.6% (95% CI of the difference -5.7 to 10.8).

CONCLUSIONS

Patients with acute exacerbations of COPD uncomplicated by acidotic respiratory failure or other medical problems can be discharged home earlier than is current practice with support by visiting respiratory nurses. No difference was found in the subsequent need for readmission.

Identification of acylpeptide hydrolase as a sensitive site for reaction with organophosphorus compounds and a potential target for cognitive enhancing drugs

We describe here the purification and identification of a previously unrecognized target for organophosphorus compounds. The target, acylpeptide hydrolase, was isolated as a tritiated-diisopropylfluorophosphate-reactive protein from porcine brain and purified to homogeneity using a combination of ion-exchange and gel-filtration chromatography. Biochemical characterization and internal sequence analysis confirmed identity. Acylpeptide hydrolase was found to be potently inhibited by the organophosphorus compounds chlorpyrifosmethyl oxon, dichlorvos, and diisopropylfluorophosphate (20-min IC(50) values of 18.3 +/- 2.0, 118.7 +/- 9.7, and 22.5 +/- 1.2 nM, respectively). The in vitro sensitivity of acylpeptide hydrolase toward these compounds is between six and ten times greater than that of acetylcholinesterase (AChE), making it a target of pharmacological and toxicological significance. We show that, in vivo, acylpeptide hydrolase is significantly more sensitive than AChE to inhibition by dichlorvos and that the inhibition is more prolonged after a single dose of inhibitor. Furthermore, using dichlorvos as a progressive inhibitor, it was possible to show that acylpeptide hydrolase is the only enzyme in the brain capable of hydrolyzing the substrate N-acetyl-alanyl-p-nitroanilide. A concentration of 154 +/- 27 pmol of acylpeptide hydrolase/gram of fresh rat brain was also deduced by specific labeling with tritiated-diisopropylfluorophosphate. We also suggest that, by comparison of structure-activity relationships, acylpeptide hydrolase may be the target for the cognitive-enhancing effects of certain organophosphorus compounds. Acylpeptide hydrolase cleaves N(alpha)-acylated amino acids from small peptides and may be involved in regulation of neuropeptide turnover, which provides a new and plausible mechanism for its proposed cognitive enhancement effect.

Aging and reflective processes of working memory: binding and test load deficits

It was hypothesized that age-related deficits in episodic memory for feature combinations (e.g., B. L. Chalfonte & M. K. Johnson, 1996) signal, in part, decrements in the efficacy of reflective component processes (e.g., M. K. Johnson, 1992) that support the short-term maintenance and manipulation of information during encoding (e.g., F. 1. M. Craik. R. G. Morris. & M. L. Gick, 1990; T. A. Salthouse, 1990). Consistent with this, age-related binding deficits in a working memory task were found in 2 experiments. Evidence for an age-related test load deficit was also found: Older adults had greater difficulty than young adults when tested on 2 features rather than 1, even when binding was not required. Thus, disruption of source memory in older adults may involve deficits in both encoding processes (binding deficits) and monitoring processes (difficulty accessing multiple features, evaluating them, or both).

fMRI evidence of age-related hippocampal dysfunction in feature binding in working memory

Richly detailed memories for particular events depend on processes that bind individual features of experience together. Previous cognitive behavioral research indicates that older adults have more difficulty than young adults in conditions requiring feature binding. We used functional magnetic resonance imaging (fMRI) during a working memory task to identify neural substrates of this age-related deficit in feature binding. For young, but not older, adults there was greater activation in left anterior hippocampus on combination trials (remember objects together with their locations) than on trials in which participants were told to remember only which objects or only which locations occurred. The results provide neuroimaging evidence for an age-related hippocampal dysfunction in feature binding in working memory.

IscU as a scaffold for iron-sulfur cluster biosynthesis: sequential assembly of [2Fe-2S] and [4Fe-4S] clusters in IscU

Iron-sulfur cluster biosynthesis in both prokaryotic and eukaryotic cells is known to be mediated by two highly conserved proteins, termed IscS and IscU in prokaryotes. The homodimeric IscS protein has been shown to be a cysteine desulfurase that catalyzes the reductive conversion of cysteine to alanine and sulfide. In this work, the time course of IscS-mediated Fe-S cluster assembly in IscU was monitored via anaerobic anion exchange chromatography. The nature and properties of the clusters assembled in discrete fractions were assessed via analytical studies together with absorption, resonance Raman, and Mössbauer investigations. The results show sequential cluster assembly with the initial IscU product containing one [2Fe-2S](2+) cluster per dimer converting first to a form containing two [2Fe-2S](2+) clusters per dimer and finally to a form that contains one [4Fe-4S](2+) cluster per dimer. Both the [2Fe-2S](2+) and [4Fe-4S](2+) clusters in IscU are reductively labile and are degraded within minutes upon being exposed to air. On the basis of sequence considerations and spectroscopic studies, the [2Fe-2S](2+) clusters in IscU are shown to have incomplete cysteinyl ligation. In addition, the resonance Raman spectrum of the [4Fe-4S](2+) cluster in IscU is best interpreted in terms of noncysteinyl ligation at a unique Fe site. The ability to assemble both [2Fe-2S](2+) and [4Fe-4S](2+) clusters in IscU supports the proposal that this ubiquitous protein provides a scaffold for IscS-mediated assembly of clusters that are subsequently used for maturation of apo Fe-S proteins.

Spectroscopic studies of the tungsten-containing formaldehyde ferredoxin oxidoreductase from the hyperthermophilic archaeon Thermococcus litoralis

The electronic and redox properties of the iron-sulfur cluster and tungsten center in the as-isolated and sulfide-activated forms of formaldehyde ferredoxin oxidoreductase (FOR) from Thermococcus litoralis (Tl) have been investigated by using the combination of EPR and variable-temperature magnetic circular dichroism (VTMCD) spectroscopies. The results reveal a [Fe4S4]2+,+ cluster (Em=-368mV) that undergoes redox cycling between an oxidized form with an S=0 ground state and a reduced form that exists as a pH- and medium-dependent mixture of S=3/2 (g=5.4; E/D=0.33) and S=1/2 (g=2.03, 1.93, 1.86) ground states, with the former dominating in the presence of 50% (v/v) glycerol. Three distinct types of W(V) EPR signals have been observed during dye-mediated redox titration of as-isolated Tl FOR. The initial resonance observed upon oxidation, termed the "low-potential" W(V) species (g=1.977, 1.898, 1.843), corresponds to approximately 25-30% of the total W and undergoes redox cycling between W(IV)/ W(V) and W(V)/W(VI) states at physiologically relevant potentials (Em= -335 and -280 mV, respectively). At higher potentials a minor "mid-potential" W(V) species, g= 1.983, 1.956, 1.932, accounting for less than 5 % of the total W, appears with a midpoint potential of -34 mV and persists up to at least + 300 mV. At potentials above 0 mV, a major "high-potential" W(V) signal, g= 1.981, 1.956, 1.883, accounting for 30-40% of the total W, appears at a midpoint potential of +184 mV. As-isolated samples of Tl FOR were found to undergo an approximately 8-fold enhancement in activity on incubation with excess Na2S under reducing conditions and the sulfide-activated Tl FOR was partially inactivated by cyanide. The spectroscopic and redox properties of the sulfide-activated Tl FOR are quite distinct from those of the as-isolated enzyme, with loss of the low-potential species and changes in both the mid-potential W(V) species (g= 1.981, 1.950, 1.931; Em = -265 mV) and high-potential W(V) species (g=1.981, 1.952, 1.895; Em = +65 mV). Taken together, the W(V) species in sulfide-activated samples of Tl FOR maximally account for only 15% of the total W. Both types of high-potential W(V) species were lost upon incubation with cyanide and the sulfide-activated high-potential species is converted into the as-isolated high-potential species upon exposure to air. Structural models are proposed for each of the observed W(V) species and both types of mid-potential and high-potential species are proposed to be artifacts of ligand-based oxidation of W(VI) species. A W(VI) species with terminal sulfido or thiol ligands is proposed to be responsible for the catalytic activity in sulfide-activated samples of Tl FOR.

Cross-modal source monitoring confusions between perceived and imagined events

Two experiments tested the prediction based on the source monitoring framework that imagination is most likely to lead to false memories when related perceived events have occurred. Consistent with this, people were more likely to falsely remember seeing events when the events had been both imagined as seen and actually heard than when they were just heard, just visually imagined, or imagined both visually and auditorily. Furthermore, when people considered potential sources for memories or more carefully evaluated features of remembered events, source errors were reduced. On average, misattributed ("false") memories differed in phenomenal qualities from true memories. Taken together, these findings show that as different qualities of mental experience flexibly enter into source attributions, qualities derived from related perceptual events are particularly likely to lead to false claims that imagined events were seen, even when the event involves a primary modality (auditory) different from the target event (visual).

Effects of epigallocatechin gallate and quercetin on oxidative damage to cellular DNA

Phenolic phytochemicals are thought to promote optimal health, partly via their antioxidant effects in protecting cellular components against free radicals. The aims of this study were to assess the free radical-scavenging activities of several common phenolic phytochemicals, and then, the effects of the most potent phenolic phytochemicals on oxidative damage to DNA in cultured cells. Epigallocatechin gallate (EGCG) scavenged the stable free radical, alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH), most effectively, while quercetin was about half as effective. Genistein, daidzein, hesperetin, and naringenin did not scavenge DPPH appreciably. Jurkat T-lymphocytes that were pre-incubated with relatively low concentrations of either EGCG or quercetin were less susceptible to DNA damage induced by either a reactive oxygen species or a reactive nitrogen species, as evaluated by the comet assay. More specifically, control cells had a comet score of only 17+/-5, indicating minimal DNA damage. Cells challenged with 25 microM hydrogen peroxide (H(2)O(2)) or 100 microM 3-morpholinosydnonimine (SIN-1, a peroxynitrite generator) had comet scores of 188+/-6 and 125+/-12, respectively, indicating extensive DNA damage. The H(2)O(2)-induced DNA damage was inhibited with 10 microM of either EGCG (comet score: 113+/-23) or quercetin (comet score: 82+/-7). Similarly, the SIN-1-mediated DNA damage was inhibited with 10 microM of either EGCG (comet score: 79+/-13) or quercetin (comet score: 72+/-17). In contrast, noticeable DNA damage was induced in Jurkat T-lymphocytes by incubating with 10-fold higher concentrations (i.e., 100 microM) of either EGCG (comet score: 56+/-17) or quercetin (comet score: 64+/-13) by themselves. Collectively, these data suggest that low concentrations of EGCG and quercetin scavenged free radicals, thereby inhibiting oxidative damage to cellular DNA. But, high concentrations of either EGCG or quercetin alone induced cellular DNA damage.

Large lung bullae in marijuana smokers

The case histories are presented of four men with multiple large upper zone lung bullae but otherwise relatively preserved lung parenchyma. Each had a history of significant exposure to marijuana. In three of the four cases the tobacco smoking load had been relatively small, suggesting a possible causal role for marijuana in the pathogenesis of this unusual pattern of bullous emphysema.

Modular organization and identification of a mononuclear iron-binding site within the NifU protein

The NifS and NifU nitrogen fixation-specific gene products are required for the full activation of both the Fe-protein and MoFe-protein of nitrogenase from Azotobacter vinelandii. Because the two nitrogenase component proteins both require the assembly of [Fe-S]-containing clusters for their activation, it has been suggested that NifS and NifU could have complementary functions in the mobilization of sulfur and iron necessary for nitrogenase-specific [Fe-S] cluster assembly. The NifS protein has been shown to have cysteine desulfurase activity and can be used to supply sulfide for the in vitro catalytic formation of [Fe-S] clusters. The NifU protein was previously purified and shown to be a homodimer with a [2Fe-2S] cluster in each subunit. In the present work, primary sequence comparisons, amino acid substitution experiments, and optical and resonance Raman spectroscopic characterization of recombinantly produced NifU and NifU fragments are used to show that NifU has a modular structure. One module is contained in approximately the N-terminal third of NifU and is shown to provide a labile rubredoxin-like ferric-binding site. Cysteine residues Cys35, Cys62, and Cys106 are necessary for binding iron in the rubredoxin-like mode and visible extinction coefficients indicate that up to one ferric ion can be bound per NifU monomer. The second module is contained in approximately the C-terminal half of NifU and provides the [2Fe-2S] cluster-binding site. Cysteine residues Cys137, Cys139, Cys172, and Cys175 provide ligands to the [2Fe-2S] cluster. The cysteines involved in ligating the mononuclear Fe in the rubredoxin-like site and those that provide the [2Fe-2S] cluster ligands are all required for the full physiological function of NifU. The only two other cysteines contained within NifU, Cys272 and Cys275, are not necessary for iron binding at either site, nor are they required for the full physiological function of NifU. The results provide the basis for a model where iron bound in labile rubredoxin-like sites within NifU is used for [Fe-S] cluster formation. The [2Fe-2S] clusters contained within NifU are proposed to have a redox function involving the release of Fe from bacterioferritin and/or the release of Fe or an [Fe-S] cluster precursor from the rubredoxin-like binding site.

Resonance Raman characterization of biotin sulfoxide reductase. Comparing oxomolybdenum enzymes in the ME(2)SO reductase family

Resonance Raman spectroscopy has been used to define active site structures for oxidized Mo(VI) and reduced Mo(IV) forms of recombinant Rhodobacter sphaeroides biotin sulfoxide reductase expressed in Escherichia coli. On the basis of (18)O/(16)O labeling studies involving water and the alternative substrate dimethyl sulfoxide and the close correspondence to the resonance Raman spectra previously reported for dimethyl sulfoxide reductase (Garton, S. D., Hilton, J., Oku, H., Crouse, B. R., Rajagopalan, K. V., and Johnson, M. K. (1997) J. Am. Chem. Soc. 119, 12906-12916), vibrational modes associated with a terminal oxo ligand and the two molybdopterin dithiolene ligands have been assigned. The results indicate that the enzyme cycles between mono-oxo-Mo(VI) and des-oxo-Mo(IV) forms with both molybdopterin dithiolene ligands remaining coordinated in both redox states. Direct evidence for an oxygen atom transfer mechanism is provided by (18)O/(16)O labeling studies, which show that the terminal oxo group at the molybdenum center is exchangeable with water during redox cycling and originates from the substrate in substrate-oxidized samples. Biotin sulfoxide reductase is not reduced by biotin or the nonphysiological products, dimethyl sulfide and trimethylamine. However, product-induced changes in the Mo=O stretching frequency provide direct evidence for a product-associated mono-oxo-Mo(VI) catalytic intermediate. The results indicate that biotin sulfoxide reductase is thermodynamically tuned to catalyze the reductase reaction, and a detailed catalytic mechanism is proposed.