Association of Incident Delirium With Short-term Mortality in Adults With Critical Illness Receiving Mechanical Ventilation

IMPORTANCE

Intensive care unit (ICU)-acquired delirium and/or coma have consequences for patient outcomes. However, contradictory findings exist, especially when considering short-term (ie, in-hospital) mortality and length of stay (LOS).

OBJECTIVE

To assess whether incident delirium, days of delirium, days of coma, and delirium- and coma-free days (DCFDs) are associated with 14-day mortality, in-hospital mortality, and hospital LOS among patients with critical illness receiving mechanical ventilation.

DESIGN, SETTING, AND PARTICIPANTS

This single-center prospective cohort study was conducted in 6 ICUs of a university-affiliated tertiary hospital in Taiwan. A total of 267 delirium-free patients (aged ≥20 years) with critical illness receiving mechanical ventilation were consecutively enrolled from August 14, 2018, to October 1, 2020.

EXPOSURES

Participants were assessed daily for the development of delirium and coma status over 14 days (or until death or ICU discharge) using the Confusion Assessment Method for the Intensive Care Unit and the Richmond Agitation-Sedation Scale, respectively.

MAIN OUTCOMES AND MEASURES

Mortality rates (14-day and in-hospital) and hospital LOS using electronic health records.

RESULTS

Of 267 participants (median [IQR] age, 65.9 [57.4-75.1] years; 171 men [64.0%]; all of Taiwanese ethnicity), 149 patients (55.8%) developed delirium for a median (IQR) of 3.0 (1.0-5.0) days at some point during their first 14 days of ICU stay, and 105 patients (39.3%) had coma episodes also lasting for a median (IQR) of 3.0 (1.0-5.0) days. The 14-day and in-hospital mortality rates were 18.0% (48 patients) and 42.1% (112 of 266 patients [1 patient withdrew from the study]), respectively. The incidence and days of delirium were not associated with either 14-day mortality (incident delirium: adjusted hazard ratio [aHR], 1.37; 95% CI, 0.69-2.72; delirium by day: aHR, 1.00; 95% CI, 0.91-1.10) or in-hospital mortality (incident delirium: aHR, 1.00; 95% CI, 0.64-1.55; delirium by day: aHR, 1.02; 95% CI, 0.97-1.07), whereas days spent in coma were associated with an increased hazard of dying during a given 14-day period (aHR, 1.16; 95% CI, 1.10-1.22) and during hospitalization (aHR, 1.10; 95% CI, 1.06-1.14). The number of DCFDs was a protective factor; for each additional DCFD, the risk of dying during the 14-day period was reduced by 11% (aHR, 0.89; 95% CI, 0.84-0.94), and the risk of dying during hospitalization was reduced by 7% (aHR, 0.93; 95% CI, 0.90-0.97). Incident delirium was associated with longer hospital stays (adjusted β = 10.80; 95% CI, 0.53-21.08) when compared with no incident delirium.

CONCLUSIONS AND RELEVANCE

In this study, despite prolonged LOS, ICU delirium was not associated with short-term mortality. However, DCFDs were associated with a lower risk of dying, suggesting that future research and intervention implementation should refocus on maximizing DCFDs to potentially improve the survival of patients receiving mechanical ventilation.

Pilot Testing of the UB-CAM Delirium Screening App

Systematic screening improves delirium detection among hospitalized older adults. This poster describes the development and pilot testing of an iOS-based app that incorporates the Ultra-Brief Confusion Assessment Method (UB-CAM), a two-step, delirium detection protocol that combines the UB-2 (2-item screener) and 3D-CAM. Previous work tested a RedCAP-based UB-CAM app in 527 patients with 399 physicians, nurses, and certified nursing assistants (CNAs) showing it can be successfully completed by all three disciplines in 97% of eligible patients in 80 seconds on average with over 85% accuracy relative to a gold standard. To improve accessibility to the clinical setting, our research team now collaborated with a computer scientist to develop and refine an iOS-based UB-CAM app for the iPhone and iPad through iterative “laboratory” testing. The app was piloted by non-clinician, research testers in hospitalized older adults (age x̄ =83, SD= 8.0) with dementia (Clinical Dementia Rating Scale x̄ =1.1, SD= .30); 64% were assessed to be delirium positive. The app demonstrated preliminary efficiency (90 seconds on average), high acceptability (100% satisfaction of users), and reliability (100% inter-rater). This project underscores the need for close collaboration between researchers, clinicians, and computer scientists with iterative testing of bedside-facing apps prior to testing with patients. Next steps include testing effectiveness in a pragmatic trial with clinician users (physicians, nurses, CNAs), integrating the UB-CAM app into the routine hospital care of all older patients. Having rapid, accurate bedside delirium detection has the potential to transform care.

The Prevention of Delirium system of care for older patients admitted to hospital for emergency care: the POD research programme including feasibility RCT

Background

Delirium is a distressing, common and serious condition in older people in hospital. Evidence suggests that it could be prevented in about one-third of patients using multicomponent interventions targeting delirium risk factors, but these interventions are not yet routinely available in the NHS.

Objective

The objective was to improve delirium prevention for older people admitted to the NHS.

Design

Project 1 comprised case studies employing qualitative methods (observation, interviews, workshops) in three NHS hospitals to develop the Prevention of Delirium system of care. Project 2 comprised case studies using mixed methods in five NHS hospitals to test the Prevention of Delirium implementation, feasibility and acceptability, and to modify the Prevention of Delirium system of care. Project 3 comprised a multicentre, cluster randomised, controlled, pragmatic feasibility study in eight hospitals, with embedded economic evaluation, to investigate the potential clinical effectiveness and cost-effectiveness of the Prevention of Delirium system of care, compared with standard care, among older patients admitted to hospital for emergency care. The primary objectives related to gathering information to design a definitive trial. Criteria for progression to a definitive trial were as follows: a minimum of six wards (75%) completing the Prevention of Delirium manual milestone checklist and an overall recruitment rate of at least 10% of the potential recruitment pool.

Setting

This study was set in NHS general hospitals.

Participants

In project 1, participants were staff, volunteers, and patient and carer representatives. In project 2, participants were staff, volunteers, patients and carers. In project 3, participants were older patients admitted to elderly care and orthopaedic trauma wards.

Intervention

The developed intervention (i.e. the Prevention of Delirium system of care).

Main outcome measures

For the feasibility study (project 3), the primary outcome measure was the Confusion Assessment Method. The secondary outcome measures were the Nottingham Extended Activities of Daily Living scale, the Clinical Anxiety Scale and the Geriatric Depression Scale Short Form.

Results

Project 1: understanding of delirium prevention was poor. Drawing on evidence, and working with ward teams, we developed the Prevention of Delirium system of care, which targeted 10 delirium risk factors. This multicomponent intervention incorporated systems and mechanisms to introduce and embed delirium prevention into routine ward practices. Project 2: five out of six wards implemented or partially implemented the Prevention of Delirium intervention. A prominent role for hospital volunteers was intended, but most wards were unable to recruit or sustain the numbers needed. We identified four conditions necessary to implement and deliver the Prevention of Delirium intervention: (1) commitment of senior nurse, (2) a named person to drive implementation forward, (3) dedicated time (1 day per week) of an experienced nurse to lead implementation and (4) adequate ward staffing levels. Overall, the intervention was acceptable to staff, volunteers, patients and carers, and did not increase nursing staff workload. In the light of these findings, the Prevention of Delirium system of care was modified for use in project 3. Project 3: 16 wards in eight hospitals (two wards per hospital) were recruited. Out of 4449 patients screened, 3274 (73.6%) were eligible and 713 were registered, resulting in a recruitment rate of 16.0%. Thirty-three (4.6%) participants withdrew. The screened and registered participants were similar, but some between-treatment group imbalances were noted among those registered to the trial. All eight wards allocated to the intervention group completed the Prevention of Delirium manual milestone checklist and delivered the Prevention of Delirium intervention (median time 18.6 weeks for implementation). Overall, fidelity to the intervention was assessed as being high in two wards, medium in five wards and low in one ward. Of the expected 5645 Confusion Assessment Method delirium assessments, 5065 (89.7%) were completed during the first 10 days of admission. The rates of return of the patient-reported questionnaire booklets were 98.0% at baseline, 81.8% at 30 days and 70.5% at 3 months. The return rate of the EuroQol-5 Dimensions questionnaire was 98.6% at baseline, 77.5% at 1 month and 65.3% at 3 months (94–98% fully completed). The completion rate of the resource use questionnaire was lower (48.7%). The number of people with new-onset delirium at 10 days was 24 (7.0%) in the Prevention of Delirium group and 33 (8.9%) in the control group. Multilevel logistic regression analysis showed that participants in the Prevention of Delirium group had non-significant lower odds of developing delirium (odds ratio 0.68, 95% confidence interval 0.37 to 1.26; p = 0.2225). The average cost of the Prevention of Delirium intervention was estimated as £10.98 per patient and the mean costs for the Prevention of Delirium and usual-care groups were £5332 and £4412, respectively, with negligible between-group differences in quality-adjusted life-years. There was conflicting evidence from the trial- and model-based analyses relating to the cost-effectiveness of the Prevention of Delirium intervention. Given this, and in view of issues with the data (e.g. high levels of missingness), the results from the economic evaluation are highly uncertain. The criteria for continuation to a future definitive randomised controlled trial were met. Such a trial would need to recruit 5200 patients in 26 hospital clusters (200 patients per cluster).

Conclusions

The Prevention of Delirium system of care was successfully developed, and a multicentre feasibility study showed that the intervention is capable of implementation and delivery in routine care, with acceptable intervention fidelity and preliminary estimate of effectiveness.

Limitations

A prominent role for volunteers was originally intended in the Prevention of Delirium system of care, but only three of the eight wards allocated to the trial intervention group involved volunteers.

Future work

The findings indicate that a definitive multicentre evaluation of the Prevention of Delirium system of care should be designed and conducted to obtain robust estimates of clinical effectiveness and cost-effectiveness.

Trial registration

Current Controlled Trials ISRCTN28213290 (project 1), ISRCTN65924234 (project 2) and ISRCTN01187372 (project 3).

Funding

This project was funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full in Programme Grants for Applied Research; Vol. 9, No. 4. See the NIHR Journals Library website for further project information.

Predictors of Caregiver Burden in Delirium: Patient and Caregiver Factors

Delirium — an acute disorder of attention and cognition — is a common, life-threatening and costly syndrome occurring frequently in older hospitalized persons. The unexpected, rapid, and volatile nature of delirium can be difficult for family caregivers to experience and may contribute to subjective feelings of distress (i.e. “delirium burden”). The aim of this study was to examine whether pre-admission patient characteristics or patient-caregiver relationship and living arrangements were associated with caregiver burden as measured by the delirium burden scale for caregivers (DEL-B-C; score 0-40, higher score is more burden). Our sample consisted of 208 older adults and their caregivers from the Better Assessment of Illness (BASIL) study, an ongoing prospective, observational study of surgical and medical patients ≥70 years old; 22% of patients experienced delirium by the Confusion Assessment Method (CAM) and the average DEL-B-C score was 7.9, 95% CI(6.95-8.88). Results indicated that neither patient-caregiver relationship and living arrangement or patient factors including pre-admission pain, sleep disturbance, or new onset incontinence were significantly correlated with delirium-related caregiver burden. However, DEL-B-C scores were significantly higher in caregivers of patients with any ADL impairment (mean 8.5 vs. 5.2, p = .016) during hospitalization although none of the individual functional deficits alone were statistically significant. This finding suggests that the association of ADL impairment and DEL-B-C scores is not driven by a single functional domain. Future studies are needed to further understand how caregiver characteristics and patient factors occurring before and during hospitalization contribute to caregiver burden after the occurrence of delirium.

Clinicians’ Knowledge and Attitudes About Delirium Detection and Management

Delirium is a serious and potentially life-threatening problem, but it remains clinically under-recognized. Various factors contribute to this under-recognition, including limited understanding of delirium, insufficient training and application of delirium assessments, potential stigma for the patient and increased workload for the clinician. As a part of an NIH funded study testing a rapid two-step delirium identification protocol at two hospitals in the U.S. (one urban and one rural), clinicians completed a 12-item survey to assess their knowledge and attitudes about delirium and their confidence in preventing and managing delirium. Survey response options followed a 5-point rating scale (strongly disagree, disagree, undecided, agree, strongly agree). The sample for this analysis included 399 clinicians (MDs=53; RNs=235; CNAs=111). Chi-square was used to test for group differences between clinician types. Less than half of the clinicians reported agreeing with the statement, “delirium is largely preventable” (MDs: 47%; RN: 44%; CNA: 41%, p-value=0.021). MDs and RNs indicated a high level of confidence in recognizing delirium while CNAs endorsed lower levels of confidence (MDs: 87%; RN: 81%; CNA: 65%, p-value=0.001). All types of clinicians reported lower confidence in managing delirium (MDs: 29%; RN: 36%; CNA: 44%, p-value=0.117). 47% of CNAs and 37% of RNs agreed there is a need for additional training in caring for persons with delirium while only 21% of MDs agreed (p = 0.031). Understanding how different types of clinicians think and feel about delirium will inform training and communication initiatives, clinical implementation, and research on best practices for delirium identification and management.

Apolipoprotein E Genotype and the Relationship Between Chitinase 3–Like Protein 1 and Postoperative Delirium

Apolipoprotein E (APOE) ɛ4 does not confer increased risk of delirium in older surgical patients; however, ɛ4 status modifies the relationship of C-reactive protein (CRP) with delirium: increased risk for delirium in ɛ4 carriers with high CRP. We examine whether APOE genotype modifies the established association between inflammatory marker chitinase-3-like protein-1 (CHI3LI/YKL-40) and delirium in patients without dementia age≥70 undergoing major non-cardiac surgery. We performed APOE genotyping using PCR, considering APOE ɛ4 vs. non-ɛ4 carriers. Plasma YKL-40, measured on postoperative day 2 by ELISA, was examined using sample-based quartiles (Q1-Q4). Delirium status was determined with daily interviews rating the Confusion Assessment Method, augmented by a validated chart review. We used generalized linear models adjusted for age, sex, surgery type, and stratified by APOE ɛ4 status. Among the 557 patients, 19% were APOE ɛ4 carriers, and 24% developed postoperative delirium. The YKL-40-delirium relationship differed by APOE status. Among APOE non-ɛ4 carriers, we found a significant relationship between YKL-40 and delirium (relative risk [RR](95% confidence interval [CI] for YKL-40 Q4 vs. Q1: 2.6(1.4-4.9) and Q3 vs. Q1: 2.3(1.2-4.5); p-trend<.01). Among APOE ɛ4 carriers, YKL-40 was not significantly associated with delirium (RR(95% CI) for YKL-40 Q4 vs. Q1: 2.0(0.6-6.6) and Q3 vs. Q1:1.1(0.3-3.5); p-trend=0.37). APOE non-ɛ4 carriers may have increased risk of delirium conferred by post-surgical inflammation specific to the type 2 immune response (high YKL-40). These results differ from prior results with CRP, and raise the possibility that APOE genotype may interact at different points in the inflammatory pathway leading to delirium.

M. POWELL LAWTON AWARD LECTURE

The M. Powell Lawton Award is presented annually to an individual who has made outstanding contributions from applied research that has benefited older people and their care. The lecture will be given by the 2018 recipient, Carol Whitlatch, PhD, Benjamin Rose Institute on Aging. The session will also include the presentation of the 2019 Lawton Award. The 2019 Lawton Award recipient is Barbara Resnick, PhD, CRNP, FGSA, of the University of Maryland. Supported by the Polisher Research Institute of the Madlyn and Leonard Abramson Center for Jewish Life.

AN INFLAMMATORY SIGNATURE OF POSTOPERATIVE DELIRIUM

Delirium is a common, morbid, and costly geriatric syndrome, yet its pathophysiology remains poorly understood. In a nested matched case-control study within the Successful Aging after Elective Surgery (SAGES) study, a cohort of adults age ≥70 without dementia undergoing major non-cardiac surgery, we previously identified inflammatory proteins to be associated with delirium. Using the entire SAGES cohort, the current study examines the independent associations of these inflammatory proteins with postoperative delirium. Plasma was collected preoperatively (PREOP) and on postoperative day 2 (POD2). Neuroinflammatory marker chitinase-3-like protein [CHI3l1 or YKL-40]; PREOP and POD2) and systemic inflammatory markers interleukin [IL]-6 (POD2 only) and C-reactive protein (CRP; PREOP and POD2) were measured using enzyme-linked immunosorbent assays. Generalized linear models were used to determine the independent (multivariable) associations between the inflammatory markers, measured in sample-based quartiles (Q). All models adjusted for age, sex, baseline cognition, surgery type, Charlson comorbidity index, and medical complications. Among the 555 patients (mean age 77 years, standard deviation, SD 5.2), 58% were female and 86% underwent orthopedic surgeries. Postoperative delirium occurred in 24%. High YKL-40 PREOP and IL-6 at POD2 (Q4 vs. Q1) were significantly associated with an increased risk of delirium: relative risk (RR) [95% confidence interval (CI)] 2.2[1.1-4.4] and 2.7[1.3-5.7], respectively. CRP (PREOP and POD2) was not significantly associated with delirium (p=0.37 and p=0.73, respectively). This work underscores the importance of inflammation (YKL-40 and IL-6) in the pathophysiology of postoperative delirium.

Ultra-brief Screeners for Detecting Delirium Superimposed on Dementia

OBJECTIVE

Delirium superimposed on dementia (DSD) is common, morbid, and costly, yet frequently undiagnosed. Our study aimed to develop a brief screening test to improve health care worker recognition of DSD.

DESIGN/SETTING/PARTICIPANTS

Older hospitalized adults with dementia were prospectively enrolled from medical and surgical inpatient units of 3 hospitals (2 in Pennsylvania, 1 in Tennessee).

MEASURES

The reference standard delirium assessment used Confusion Assessment Method (CAM) criteria and was based on a structured interview including the Mini-Mental State Examination, interviewer observations, and medical record review. To develop the screening test, 1-, 2-, and 3-item combinations from the reference standard assessment were analyzed to determine their sensitivity and specificity in diagnosing delirium presence in a dementia population compared to the reference standard. For multiple-item screeners, error on 1 or more items was considered a positive screen.

RESULTS

Overall, 391 older adults with dementia were enrolled (mean age: 83.9 years, 71.1% female), and 95 (24.4%) developed DSD during their hospitalization, based on the reference standard. The best single-item screen for DSD was "What day of the week is it?" with 84% sensitivity [95% confidence interval (CI): 0.75, 0.91] and 41% specificity (CI: 0.35, 0.47). The best 2-item screen was "list the days of the week backwards" and "What day of the week is it?" with 93% sensitivity (CI: 0.85, 0.97) and 30% specificity (CI: 0.25, 0.36). The best 3-item screen was "list the days of the week backwards," "What type of place is this? [hospital]" and "Does the patient appear sleepy?" with 94% sensitivity (CI: 0.87, 0.98) and 42% specificity (CI: 0.36, 0.48).

CONCLUSIONS/IMPLICATIONS

We identified a 3-item DSD screener with excellent sensitivity but limited specificity. This screener can be used to quickly rule out DSD in populations with a high prevalence of dementia and is a promising step toward developing efficient tools for DSD recognition among care providers.

Recommendations for the nomenclature of cognitive change associated with anaesthesia and surgery-2018

Cognitive change affecting patients after anaesthesia and surgery has been recognised for more than 100 yr. Research into cognitive change after anaesthesia and surgery accelerated in the 1980s when multiple studies utilised detailed neuropsychological testing for assessment of cognitive change after cardiac surgery. This body of work consistently documented decline in cognitive function in elderly patients after anaesthesia and surgery, and cognitive changes have been identified up to 7.5 yr afterwards. Importantly, other studies have identified that the incidence of cognitive change is similar after non-cardiac surgery. Other than the inclusion of non-surgical control groups to calculate postoperative cognitive dysfunction, research into these cognitive changes in the perioperative period has been undertaken in isolation from cognitive studies in the general population. The aim of this work is to develop similar terminology to that used in cognitive classifications of the general population for use in investigations of cognitive changes after anaesthesia and surgery. A multispecialty working group followed a modified Delphi procedure with no prespecified number of rounds comprised of three face-to-face meetings followed by online editing of draft versions. Two major classification guidelines [Diagnostic and Statistical Manual for Mental Disorders, fifth edition (DSM-5) and National Institute for Aging and the Alzheimer Association (NIA-AA)] are used outside of anaesthesia and surgery, and may be useful for inclusion of biomarkers in research. For clinical purposes, it is recommended to use the DSM-5 nomenclature. The working group recommends that 'perioperative neurocognitive disorders' be used as an overarching term for cognitive impairment identified in the preoperative or postoperative period. This includes cognitive decline diagnosed before operation (described as neurocognitive disorder); any form of acute event (postoperative delirium) and cognitive decline diagnosed up to 30 days after the procedure (delayed neurocognitive recovery) and up to 12 months (postoperative neurocognitive disorder).

Isotopic Shift of Atom-Dimer Efimov Resonances in K-Rb Mixtures: Critical Effect of Multichannel Feshbach Physics

Multichannel Efimov physics is investigated in ultracold heteronuclear admixtures of K and Rb atoms. We observe a shift in the scattering length where the first atom-dimer resonance appears in the ^{41}K-^{87}Rb system relative to the position of the previously observed atom-dimer resonance in the ^{40}K-^{87}Rb system. This shift is well explained by our calculations with a three-body model including van der Waals interactions, and, more importantly, multichannel spinor physics. With only minor differences in the atomic masses of the admixtures, the shift in the atom-dimer resonance positions can be cleanly ascribed to the isolated and overlapping Feshbach resonances in the ^{40}K-^{87}Rb and ^{41}K-^{87}Rb systems, respectively. Our study demonstrates the role of multichannel Feshbach physics in determining Efimov resonances in heteronuclear three-body systems.

Narrow-linewidth light source for a coherent Raman transfer of ultracold molecules

We describe a tunable two-color CW light source sufficient for realizing a coherent Raman transfer between two molecular states that are more than 0.5 eV (120 THz) apart. The simultaneous frequency stabilization of 901 nm and 655 nm light was achieved by locking diode lasers to a single ultralow expansion cavity with dual wavelengths coating. By utilizing offset-locking and optical phase-locked loop (OPLL), we ensured a large mode-hop free tuning range (> 2 GHz). The obtained short term linewidth (<10 Hz) and the linear drift of frequency (65 mHz/s) were both sufficient to eliminate the influence of laser linewidths on the efficiency of coherent Raman transition.

Identification of a functional luciferase gene in the non-luminous diurnal firefly, Lucidina biplagiata

We isolated a luciferase gene (LbLuc) from the non-luminous diurnal firefly, Lucidina biplagiata, with high similarity to that from the nocturnal firefly, Photinus pyralis. The recombinant LbLuc showed luminescence activity comparable to that of the luciferases from P. pyralis and Luciola cruciata. To understand the non-luminosity of L. biplagiata, we determined the amount of luciferase in the adult specimen using the luciferin-luciferase reaction and found that the content of luciferase in L. biplagiata was estimated to be only 0.1% of that in L. cruciata. As previously reported, the content of luciferin in L. biplagiata was less than 0.1% of that in L. cruciata. Thus, the non-luminosity of L. biplagiata might be explained by low levels of both luciferase and luciferin.

Coherent transfer of photoassociated molecules into the rovibrational ground state

We report on the direct conversion of laser-cooled 41K and 87Rb atoms into ultracold 41K87Rb molecules in the rovibrational ground state via photoassociation followed by stimulated Raman adiabatic passage. High-resolution spectroscopy based on the coherent transfer revealed the hyperfine structure of weakly bound molecules in an unexplored region. Our results show that a rovibrationally pure sample of ultracold ground-state molecules is achieved via the all-optical association of laser-cooled atoms, opening possibilities to coherently manipulate a wide variety of molecules.

Site-specific mutagenesis of the calcium-binding photoprotein aequorin

The luminescent protein aequorin from the jellyfish Aequoria victoria emits light by an intramolecular reaction in the presence of a trace amount of Ca(2+). In order to understand the mechanism of the reaction, a study of structure-function relationships was undertaken with respect to modifying certain of its amino acid residues. This was done by carrying out oligonucleotide-directed site-specific mutagenesis of apoaequorin cDNA and expressing the mutagenized cDNA in Escherichia coli. Amino acid substitutions were made at the three Ca(2+)-binding sites, the three cysteines, and a histidine in one of the hydrophobic regions. Subsequent assay of the modified aequorin showed that the Ca(2+)-binding sites, the cysteines, and probably the histidine all play a role in the bioluminescence reaction of aequorin.

Cloning and characterization of the homologous genes of firefly luciferase in the mealworm beetle, Tenebrio molitor

Three homologous genes of firefly luciferase were cloned from the non-luminous beetle Tenebrio molitor. Three gene products for homologues, TmLL-1, TmLL-2 and TmLL-3, showed fatty acyl-coenzyme A (acyl-CoA) synthetic activity, but not luciferase activity with firefly luciferin. The transcripts were detected through the developmental stages in T. molitor. These results suggested that firefly luciferase was evolved from a fatty acyl-coenzyme A synthetase by gene duplications in the insect.

Retrons, msDNA, and the bacterial genome

Retrons are distinct DNA sequences that code for a reverse transcriptase (RT) similar to the RTs produced by retroviruses and other types of retroelements. Retron DNAs are commonly associated with prophage DNA and are found in the genomes of a wide variety of different bacteria. The retron RT is used to synthesize a strange satellite DNA known as msDNA. msDNA is actually a complex of DNA, RNA, and probably protein. It is composed of a small, single-stranded DNA, linked to a small, single-stranded RNA molecule. The 5' end of the DNA molecule is joined to an internal guanosine residue of the RNA molecule by a unique 2'-5' phosphodiester bond. msDNA is produced in many hundreds of copies per cell, but its function remains unknown. Although retrons are absent from the genome of most members of a population of related bacteria, retrons may not be entirely benign DNAs. Evidence is beginning to suggest that retron elements may produce small but potentially significant effects on the host cell. This includes the generation of repeated copies of the msDNA sequence in the genome, and increasing the frequency of spontaneous mutations. Because these events involve the retron RT, this may represent a source of reverse transcription in the bacterial cell. Thus, the process of reverse transcription, a force that has profoundly affected the content and structure of most eukaryotic genomes, may likewise be responsible for changes in some prokaryotic genomes.

Direct nondestructive imaging of magnetization in a spin-1 Bose-Einstein gas

Polarization-dependent phase-contrast imaging is used to resolve the spatial magnetization profile of an optically trapped ultracold gas. This probe is applied to Larmor precession of degenerate and nondegenerate spin-1 87Rb gases. Transverse magnetization of the Bose-Einstein condensate persists for the condensate lifetime, with a spatial response to magnetic field inhomogeneities consistent with a mean-field model of interactions. In comparison, the magnetization of the non-condensed gas decoheres rapidly. Rotational symmetry implies that the Larmor frequency of a spinor condensate be density independent, and thus suitable for precise magnetometry with high spatial resolution.

Observation of heteronuclear Feshbach resonances in a mixture of bosons and fermions

Three magnetic-field induced heteronuclear Feshbach resonances were identified in collisions between bosonic 87Rb and fermionic 40K atoms in their absolute ground states. Strong inelastic loss from an optically trapped mixture was observed at the resonance positions of 492, 512, and 543+/-2 G. The magnetic-field locations of these resonances place a tight constraint on the triplet and singlet cross-species scattering lengths, yielding (-281+/-15)a(0) and (-54+/-12)a(0), respectively. The width of the loss feature at 543 G is 3.7+/-1.5 G wide; this broad Feshbach resonance should enable experimental control of the interspecies interactions.

Sodium Bose-Einstein condensates in the F = 2 state in a large-volume optical trap

We have investigated the properties of Bose-Einstein condensates of sodium atoms in the upper hyperfine ground state. Condensates in the high-field seeking [F=2, m(F)=-2> state were created in a large volume optical trap from initially prepared [F=1, m(F)=-1> condensates using a microwave transition at 1.77 GHz. We found condensates in the stretched state [F=2, m(F)=-2> to be stable for several seconds at densities in the range of 10(14) atoms/cm(3). In addition, we studied the clock transition [F=1, m(F)=0> --> [F=2, m(F)=0> in a sodium Bose-Einstein condensate and determined a density-dependent frequency shift of (2.44+/-0.25+/-0.5) x 10(-12) Hz cm(3).

Analysis of sequential immunoglobulin E-binding epitope of Japanese cedar pollen allergen (Cry j 2) in humans, monkeys and mice

BACKGROUND

Japanese cedar (Cryptomeria japonica; CJ) pollinosis has been reported to occur naturally in Japanese monkeys (Macaca fuscata) as well as in humans. Most human patients and monkeys with pollinosis have specific IgE for Cry j 2, a major allergen of CJ pollen.

OBJECTIVE

The main purpose of this study was to identify IgE B cell epitopes of Cry j 2 using a synthetic peptide in humans, monkeys and mice.

METHODS

We synthesized 38 overlapping peptides that span the entire length of Cry j 2. We examined the B cell epitopes of Cry j 2 that are recognized by IgE in the sera of human patients and monkeys with pollinosis and immunized mice using synthetic peptides of Cry j 2. We also examined the reaction of Cry j 2-specific mouse monoclonal IgG antibodies to the peptides. Furthermore, we conducted a histamine release assay with leucocytes from a pollinosis patient using human serum albumin (HSA) conjugated with the peptides as a B cell epitope.

RESULTS

We found that 16 of the 20 pollinosis patients who had specific IgE to Cry j 2 also exhibited IgE reaction with some Cry j 2 peptides. Of these 16 patients, 10 exhibited IgE reaction with Cry j 2 peptide no. 13 (121GQCKWVNGREICNDRDRPTA140). Five of the seven monkeys with CJ pollinosis exhibited a reaction with peptide no. 13. Furthermore, IgE in mice immunized with Cry j 2 and two mouse monoclonal IgG antibodies reacted with peptide no. 13. Peptide no. 13-conjugated HSA showed the release of histamine from basophils. Furthermore, to determine the minimum epitope in peptide no. 13, we conducted an enzyme-linked immunosorbent assay inhibition test. The core of the epitope in humans, monkeys and mice was 124KWVNGREI131.

CONCLUSION

We found that 124KWVNGREI131 is an important B cell epitope recognized by IgE in humans, monkeys and mice.

Analysis of HLA in children with gelatin allergy

Systemic immediate reactions including anaphylaxis to gelatin in vaccines have been reported. However, the number of such reports is very small compared with the number of children exposed to gelatin. The present study was designed to investigate whether susceptibility or resistance to gelatin allergy is associated with human leukocyte antigen (HLA) class II gene. Blood samples were obtained from 49 patients with gelatin allergy and specific IgE to gelatin. DNA-based HLA class II typing was performed to determine the DRB1, DQB1 and DPB1 alleles. Genotype frequencies were compared with those found in 240 unrelated controls. The frequency of DQB1*0303 (55.1%) was significantly higher in the patients than in the control subjects (32.1%). The frequency of DPB1*0402 was also significantly higher in the patients (32.7%) than in the control subjects (15.4%). On the other hand, the frequency of subjects carrying DRB1*15 (DRB1*1501 and DRB1*1502) was significantly lower among the patients group (18.4%) than among the controls (40.8%). We found that DQB1*0303 and DPB1*0402 were positively associated with the IgE response for gelatin, while DRB1*15 was negatively associated with it.

Prolipoprotein signal peptidase of Escherichia coli requires a cysteine residue at the cleavage site

A signal peptidase specifically required for the secretion of the lipoprotein of the Escherichia coli outer membrane cleaves off the signal peptide at the bond between a glycine and a cysteine residue. This cysteine residue was altered to a glycine residue by guided site-specific mutagenesis using a synthetic oligonucleotide and a plasmid carrying an inducible lipoprotein gene. The induction of mutant lipoprotein production was lethal to the cells. A large amount of the prolipoprotein was accumulated in the outer membrane fraction. No protein of the size of the mature lipoprotein was detected. These results indicate that the prolipoprotein signal peptidase requires a glyceride modified cysteine residue at the cleavage site.

Screening of the antibacterial effects of a variety of essential oils on respiratory tract pathogens, using a modified dilution assay method

The purpose of this study was to examine the antibacterial effects of a wide variety of essential oils on major respiratory tract pathogens. The antibacterial activity of 14 essential oils and their major components was evaluated by agar-plate dilution assay under sealed conditions, with agar used as a stabilizer for homogeneous dispersion. Of the selected strains of four major bacteria causing respiratory tract infection, Haemophilus influenzae was most susceptible to the essential oils, followed by Streptococcus pneumoniae and Streptococcus pyogenes. Staphylococcus aureus was less susceptible. No cross-resistance was observed between penicillin-sensitive and penicillin-resistant S. pneumoniae. Escherichia coli, used as a control bacterium, showed the lowest susceptibility. Essential oils containing aldehyde or phenol as a major component showed the highest antibacterial activity, followed by the essential oils containing terpene alcohols. Other essential oils, containing terpene ketone, or ether, had much weaker activity, and an oil containing terpene hydrocarbon was inactive. Based on these findings, thyme (wild, red, and geraniol types), cinnamon bark, lemongrass, perilla, and peppermint oils were selected for further evaluation of their effects on respiratory tract infection.

Isolation and properties of the luciferase stored in the ovary of the scyphozoan medusa Periphylla periphylla

Bioluminescence of the medusa Periphylla is based on the oxidation of coelenterazine catalyzed by luciferase. Periphylla has two types of luciferase: the soluble form luciferase L, which causes the exumbrellar bioluminescence display of the medusa, and the insoluble aggregated form, which is stored as particulate material in the ovary, in an amount over 100 times that of luciferase L. The eggs are especially rich in the insoluble luciferase, which drastically decreases upon fertilization. The insoluble form could be solubilized by 2-mercaptoethanol, yielding a mixture of luciferase oligomers with molecular masses in multiples of approximately 20 kDa. Those having the molecular masses of 20 kDa, 40 kDa, and 80 kDa were isolated and designated, respectively, as luciferase A, luciferase B, and luciferase C. The luminescence activities of Periphylla luciferases A, B, and C were 1.2 approximately 4.1 x 10(16) photon/mg. s, significantly higher than any coelenterazine luciferase known, and the quantum yields of coelenterazine catalyzed by these luciferases (about 0.30 at 24 degrees C) are comparable to that catalyzed by Oplophorus luciferase (0.34 at 22 degrees C), which has been considered the most efficient coelenterazine luciferase until now. Luciferase L (32 kDa) could also be split by 2-mercaptoethanol into luciferase A and an accessory protein (approx. 12 kDa), as yet uncharacterized. Luciferases A, B, and C are highly resistant to inactivation: their luminescence activities are only slightly diminished at pH 1 and pH 11 and are enhanced in the presence of 1 approximately 2 M guanidine hydrochloride; but they are less stable to heating than luciferase L, which is practically unaffected by boiling.

Anaphylaxis to gelatin-containing rectal suppositories

BACKGROUND

Some children--though the number is few-have been sensitized with gelatin.

OBJECTIVE

To investigate the relationship between the presence of antigelatin IgE and anaphylaxis to gelatin-containing rectal suppository, we measured antigelatin IgE in the sera of the children with anaphylaxis.

METHODS

Ten children showed systemic allergic reactions, including anaphylaxis, to a chloral hydrate rectal suppository containing gelatin (231 mg/dose) that had been used as a sedative. These children's clinical histories and serum samples were submitted from physicians to the National Institute of Infectious Diseases during a 2-year period from 1996 to 1997.

RESULTS

Of the 10 children, 5 showed apparent anaphylaxis, including hypotension and/or cyanosis, along with urticaria or wheezing; 2 showed both urticaria and wheezing without hypotension or cyanosis; the other 3 showed only urticaria. All of the children had antigelatin IgE (mean value +/- SD, 7.9 +/- 8.4 Ua/mL). As a control, samples from 250 randomly selected children had no antigelatin IgE. These findings suggest that the 10 children's systemic allergic reactions to this suppository were caused by the gelatin component.

CONCLUSION

Gelatin-containing suppositories must be used with the same caution as gelatin-containing vaccines and other medications.

Heat-shock-induced proteins from Myxococcus xanthus

Optimal conditions for two-dimensional gel electrophoresis of total cellular proteins from Myxococcus xanthus were established. Using these conditions, we analyzed protein patterns of heat-shocked M. xanthus cells. Eighteen major spots and 15 minor spots were found to be induced by heat shock. From N-terminal sequences of 15 major spots, DnaK, GroEL, GroES, alkyl hydroperoxide reductase, aldehyde dehydrogenase, succinyl coenzyme A (CoA) synthetase, 30S ribosomal protein S6, and ATP synthase alpha subunit were identified. Three of the 18 major spots had an identical N-terminal sequence, indicating that they may be different forms of the same protein. Although a DnaK homologue, SglK, has been identified in M. xanthus (R. M. Weimer, C. Creghton, A. Stassinopoulos, P. Youderian, and P. L. Hartzell, J. Bacteriol. 180:5357-5368, 1998; Z. Yang, Y. Geng, and W. Shi, J. Bacteriol. 180:218-224, 1998), SglK was not induced by heat shock. In addition, there were seven substitutions within the N-terminal 30-residue sequence of the newly identified DnaK. This is the first report to demonstrate that succinyl CoA synthetase, 30S ribosomal protein S6, and ATP synthase alpha subunit are heat shock inducible.

Use of antiserum-coated latex particles for serotyping Streptococcus pneumoniae

The Quellung reaction provides a standard means for serotyping Streptococcus pneumoniae, but it requires microscopic examination with skillful technique. We have developed an improved agglutination method with anti-rabbit IgG-coated latex particles, which are sensitized with pooled antisera for serotyping/serogrouping S. pneumoniae. Our method is as specific and sensitive as the Quellung test, and much easier to perform.

Realization of Bose-Einstein condensates in lower dimensions

Bose-Einstein condensates of sodium atoms have been prepared in optical and magnetic traps in which the energy-level spacing in one or two dimensions exceeds the interaction energy between atoms, realizing condensates of lower dimensionality. The crossover into two-dimensional and one-dimensional condensates was observed by a change in aspect ratio and by the release energy converging to a nonzero value when the number of trapped atoms was reduced.

Effect of sealing and Tween 80 on the antifungal susceptibility testing of essential oils

Concentrations of essential oils showing high volatility decreased substantially in broth and agar media when incubated under open conditions. The decrease in the half life was from 0.7 to 38 hr in broth medium at 27 C. When evaporation was prevented by sealing, MIC values against Aspergillus fumigatus, Candida albicans and Trichophyton mentagrophytes by broth or agar dilution assay were lowered two to eight-fold, as compared with those obtained under open conditions. Addition of Tween 80 caused a rise of the MICs against A. fumigatus by two to four-fold in broth dilution assay, but little affected the MICs in agar dilution assay.

The msDNAs of bacteria

msDNAs are small, structurally unique satellite DNAs found in a number of Gram-negative bacteria. Composed of hundreds of copies of single-stranded DNA--hence the name multicopy single-stranded DNA--msDNA is actually a complex of DNA, RNA, and probably protein. These peculiar molecules are synthesized by a reverse transcription mechanism catalyzed by a reverse transcriptase (RT) that is evolutionarily related to the polymerase found in the HIV virus. The genes, including the RT gene, responsible for the synthesis of msDNA are encoded in a retron, a genetic element that is carried on the bacterial chromosome. The retron is, in fact, the first such retroelement to be discovered in prokaryotic cells. This report is a comprehensive review of the many interesting questions raised by this unique DNA and the fascinating answers it has revealed. We have learned a great deal about the structure of msDNA: how it is synthesized, the structure and functions of the RT protein required to make it, its effects on the host cell, the retron element that encodes it, its possible origins and evolution, and even its potential usefulness as a practical genetic tool. Despite the impressive gains in our understanding of the msDNAs, however, the simple, fundamental question of its natural function remains an enduring mystery. Thus, we have much more to learn about the msDNAs of bacteria.

Observation of vortex phase singularities in Bose-Einstein condensates

We have observed phase singularities due to vortex excitation in Bose-Einstein condensates. Vortices were created by moving a laser beam through a condensate. They were observed as dislocations in the interference fringes formed by the stirred condensate and a second unperturbed condensate. The velocity dependence for vortex excitation and the time scale for re-establishing a uniform phase across the condensate were determined.

The role of nitric oxide in the gastric acid secretion induced by ischemia-reperfusion in the pylorus-ligated rat

In a rat model of the ischemia-reperfusion with pylorus ligation, gastric ulcer was formed, although gastric acid secretion was reduced. When the polymorphonuclear leukocytes were inactivated in advance, gastric ulcer was not formed, but acid secretion was increased, indicating that gastric acid is not a cause of the ulcer formation in this model. The mechanism of gastric acid suppression accompanied by ischemia-reperfusion was examined in relation to the role of oxygen-free radicals in this rat model. Prior administration of superoxide dismutase did not modulate acid secretion, but N-nitro-L-arginine methyl ester (L-NAME) increased acid secretion. The action of L-NAME was antagonized specifically by L-arginine, but not by D-arginine. S-nitroso-N-acetylpenicillamine did not inhibit basal acid secretion but antagonized the action of L-NAME. Aminoguanidine increased significantly the gastric acid output that was suppressed by ischemia-reperfusion. When polymorphonuclear leukocytes were inactivated by treatment with their antibody, the gastric acid output recovered to the level in the pylorus-ligated rat without ischemia-reperfusion. These results suggested that nitric oxide (NO) produced by the infiltrated polymorphonuclear leukocytes plays an important role in the suppression of acid secretion induced by ischemia-reperfusion.

Preclinical evaluation of an immunotherapeutic peptide comprising 7 T-cell determinants of Cry j 1 and Cry j 2, the major Japanese cedar pollen allergens

BACKGROUND

Peptide immunotherapy is a new approach to treating allergic diseases, but a therapeutic peptide for Japanese cedar pollinosis has not yet been developed.

OBJECTIVE

The aim of this study is to prepare and preclinically evaluate a hybrid peptide comprising 7 T-cell determinants of Cry j 1 and Cry j 2, the major Japanese cedar pollen allergens.

METHODS

The recombinant hybrid peptide was prepared after immunodominance of 7 T-cell determinants was confirmed by means of PBMC proliferation assay in 113 volunteers with pollinosis. The hybrid peptide was compared with a mixture of the 7 T-cell determinants in a dose-dependent PBMC proliferation assay in 6 volunteers with pollinosis. PBMC proliferation and binding activity of serum IgE antibody against the hybrid peptide, Cry j 1, and Cry j 2 were investigated in 48 volunteers with pollinosis.

RESULTS

The hybrid peptide induced T-cell proliferation with an average 100-fold lower concentration than a mixture of the 7 peptides. PBMCs from 44 (92%) of 48 volunteers proliferated against the hybrid peptide, with significant correlation (r = 0.87) in T-cell proliferation against Cry j 1 and Cry j 2. No serum IgE antibodies specific to Cry j 1 or Cry j 2 bound to the hybrid peptide.

CONCLUSION

A hybrid peptide comprising 7 T-cell determinants has the potential for inducing T-cell proliferative responses that is superior to the potential of a mixture of the T-cell determinants and comparable with that of Cry j 1 and Cry j 2. The hybrid peptide will be of use in specific immunotherapy against Japanese cedar pollinosis.