Neuroprotection by acrolein sequestration through exogenously applied scavengers and endogenous enzymatic enabling strategies in mouse EAE model

We have previously shown that the pro-oxidative aldehyde acrolein is a critical factor in MS pathology. In this study, we found that the acrolein scavenger hydralazine (HZ), when applied from the day of induction, can suppress acrolein and alleviate motor and sensory deficits in a mouse experimental autoimmune encephalomyelitis (EAE) model. Furthermore, we also demonstrated that HZ can alleviate motor deficits when applied after the emergence of MS symptoms, making potential anti-acrolein treatment a more clinically relevant strategy. In addition, HZ can reduce both acrolein and MPO, suggesting a connection between acrolein and inflammation. We also found that in addition to HZ, phenelzine (PZ), a structurally distinct acrolein scavenger, can mitigate motor deficits in EAE when applied from the day of induction. This suggests that the likely chief factor of neuroprotection offered by these two structurally distinct acrolein scavengers in EAE is their common feature of acrolein neutralization. Finally, up-and-down regulation of the function of aldehyde dehydrogenase 2 (ALDH2) in EAE mice using either a pharmacological or genetic strategy led to correspondent motor and sensory changes. This data indicates a potential key role of ALDH2 in influencing acrolein levels, oxidative stress, inflammation, and behavior in EAE. These findings further consolidate the critical role of aldehydes in the pathology of EAE and its mechanisms of regulation. This is expected to reinforce and expand the possible therapeutic targets of anti-aldehyde treatment to achieve neuroprotection through both endogenous and exogenous manners.

The Effects of a News Literacy Video and Real-Time Corrections to Video Misinformation Related to Sunscreen and Skin Cancer

Given concerns about the persuasive power of video misinformation on social media for health topics, we test two techniques - exposure to a news literacy video and user corrections - to limit the effects on misperceptions. An online sample of American adults from August of 2019 was randomly assigned to view two simulated Facebook videos. The first video manipulated the presence of news literacy concepts. The second video either promoted sunscreen use or made inaccurate claims regarding its dangers; scrolling comments either debunked or did not address the sunscreen misinformation in the video. Our results demonstrate that video misinformation heightened beliefs in sunscreen myths and reduced acceptance of sunscreen facts and intentions to wear sunscreen compared to a promotional video. Real-time user corrections were partially successful in reducing the effects of the misinformation video on beliefs but not intentions. Additionally, exposure to a news literacy video did not inoculate people to the misinformation. We discuss the implications of these findings for best practices regarding correcting video misinformation on health topics.

Evaluation of electropolymerized molecularly imprinted polymers (E-MIPs) on disposable electrodes for detection of SARS-CoV-2 in saliva

We investigate electropolymerized molecularly imprinted polymers (E-MIPs) for the selective recognition of SARS-CoV-2 whole virus. E-MIPs imprinted with SARS-CoV-2 pseudoparticles (pps) were electrochemically deposited onto screen printed electrodes by reductive electropolymerization, using the water-soluble N-hydroxmethylacrylamide (NHMA) as functional monomer and crosslinked with N,N'-methylenebisacrylamide (MBAm). E-MIPs for SARS-CoV-2 showed selectivity for template SARS-CoV-2 pps, with an imprinting factor of 3:1, and specificity (significance = 0.06) when cross-reacted with other respiratory viruses. E-MIPs detected the presence of SARS-CoV-2 pps in <10 min with a limit of detection of 4.9 log10 pfu/mL, suggesting their suitability for detection of SARS-CoV-2 with minimal sample preparation. Using electrochemical impedance spectroscopy (EIS) and principal component analysis (PCA), the capture of SARS-CoV-2 from real patient saliva samples was also evaluated. Fifteen confirmed COVID-19 positive and nine COVID-19 negative saliva samples were compared against the established loop-mediated isothermal nucleic acid amplification (LAMP) technique used by the UK National Health Service. EIS data demonstrated a PCA discrimination between positive and negative LAMP samples. A threshold real impedance signal (ZRe) ≫ 4000 Ω and a corresponding charge transfer resistance (RCT) ≫ 6000 Ω was indicative of absence of virus (COVID-19 negative) in agreement with values obtained for our control non-imprinted polymer control. A ZRe at or below a threshold value of 600 Ω with a corresponding RCT of <1200 Ω was indicative of a COVID-19 positive sample. The presence of virus was confirmed by treatment of E-MIPs with a SARS-CoV-2 specific monoclonal antibody.

Systemic Acrolein Elevations in Mice With Experimental Autoimmune Encephalomyelitis and Patients With Multiple Sclerosis

Demyelination and axonal injury are the key pathological processes in multiple sclerosis (MS), driven by inflammation and oxidative stress. Acrolein, a byproduct and instigator of oxidative stress, has been demonstrated as a neurotoxin in experimental autoimmune encephalomyelitis (EAE), an animal model of MS. However, due to the invasive nature of acrolein detection using immunoblotting techniques, the investigation of acrolein in MS has been limited to animal models. Recently, detection of a specific acrolein-glutathione metabolite, 3-HPMA, has been demonstrated in urine, enabling the noninvasive quantification of acrolein for the first time in humans with neurological disorders. In this study, we have demonstrated similar elevated levels of acrolein in both urine (3-HPMA) and in spinal cord tissue (acrolein-lysine adduct) in mice with EAE, which can be reduced through systemic application of acrolein scavenger hydralazine. Furthermore, using this approach we have demonstrated an increase of 3-HPMA in both the urine and serum of MS patients relative to controls. It is expected that this noninvasive acrolein detection could facilitate the investigation of the role of acrolein in the pathology of MS in human. It may also be used to monitor putative therapies aimed at suppressing acrolein levels, reducing severity of symptoms, and slowing progression as previously demonstrated in animal studies.

Elevated axonal membrane permeability and its correlation with motor deficits in an animal model of multiple sclerosis

Background

It is increasingly clear that in addition to myelin disruption, axonal degeneration may also represent a key pathology in multiple sclerosis (MS). Hence, elucidating the mechanisms of axonal degeneration may not only enhance our understanding of the overall MS pathology, but also elucidate additional therapeutic targets. The objective of this study is assess the degree of axonal membrane disruption and its significance in motor deficits in EAE mice.

Methods

Experimental Autoimmune Encephalomyelitis was induced in mice by subcutaneous injection of myelin oligodendrocyte glycoprotein/complete Freud’s adjuvant emulsion, followed by two intraperitoneal injections of pertussis toxin. Behavioral assessment was performed using a 5-point scale. Horseradish Peroxidase Exclusion test was used to quantify the disruption of axonal membrane. Polyethylene glycol was prepared as a 30% (w/v) solution in phosphate buffered saline and injected intraperitoneally.

Results

We have found evidence of axonal membrane disruption in EAE mice when symptoms peak and to a lesser degree, in the pre-symptomatic stage of EAE mice. Furthermore, polyethylene glycol (PEG), a known membrane fusogen, significantly reduces axonal membrane disruption in EAE mice. Such PEG-mediated membrane repair was accompanied by significant amelioration of behavioral deficits, including a delay in the emergence of motor deficits, a delay of the emergence of peak symptom, and a reduction in the severity of peak symptom.

Conclusions

The current study is the first indication that axonal membrane disruption may be an important part of the pathology in EAE mice and may underlies behavioral deficits. Our study also presents the initial observation that PEG may be a therapeutic agent that can repair axolemma, arrest axonal degeneration and reduce motor deficits in EAE mice.

School Administrator Perceptions of Cyberbullying Facilitators and Barriers to Preventive Action: A Qualitative Study

BACKGROUND

Schools are often held responsible for preventing or addressing cyberbullying, yet little is known about school administrator perceptions of cyberbullying and the challenges they face in addressing this public health issue.

AIMS

The goal of this study is to examine school administrators' perceptions of the facilitators of cyberbullying and barriers to primary and secondary prevention strategies.

METHOD

Public school administrators ( N = 36) participated in in-depth interviews about bullying and discussed their experiences with cyberbullying and their perceptions of cyberbullying facilitators and barriers to prevention.

RESULTS

Three main themes arose from the analysis: (1) cyberbullying as a major challenge; (2) facilitators of cyberbullying and barriers to preventive action, including parents and technology; and (3) prevention efforts, including unclear jurisdiction for action, primary versus secondary prevention efforts, and technology attributes that facilitate school response to bullying.

DISCUSSION

Although administrators perceive cyberbullying as a major challenge facing their schools, they are often unsure about appropriate primary and secondary prevention efforts. Relationships with parents and police complicate response and prevention as schools attempt to navigate unclear jurisdiction. Additionally, technology presents a challenge to schools because it is seen as an enabler of cyberbullying, a facilitator of prevention, and a necessary part of education efforts.

CONCLUSION

Lack of research on prevention strategies, parents' knowledge and attitudes, and confusion about responsibility for addressing cyberbullying are barriers to action. Findings suggest administrators could benefit from additional clarity on which strategies are most effective for primary prevention of cyberbullying, and that prevention strategies should proactively involve parents to promote effective collaboration with schools.

Media Literacy Training Reduces Perception of Bias

Researchers found those exposed to a media literacy presentation were less likely to perceive a story on a controversial issue to be biased.

Effectiveness of a Non-Classroom News Media Literacy Intervention Among Different Undergraduate Populations

In this study, we test the effectiveness of a short news media literacy message with audiences who differ in their media literacy education. We manipulate whether individuals are exposed to a news media literacy public service announcement (PSA) immediately before viewing a political program among two groups: students enrolled in media education courses versus students in a non-media course. Findings suggest that the ability of media literacy messages to influence students’ processing of the subsequent political program is conditioned by their preexisting media literacy education. This study provides insights for considering how classroom and non-classroom media literacy interventions can work together to improve media literacy.

Molecular mechanisms of acrolein-mediated myelin destruction in CNS trauma and disease

Myelin is a critical component of the nervous system facilitating efficient propagation of electrical signals and thus communication between the central and peripheral nervous systems and the organ systems that they innervate throughout the body. In instances of neurotrauma and neurodegenerative disease, injury to myelin is a prominent pathological feature responsible for conduction deficits, and leaves axons vulnerable to damage from noxious compounds. Although the pathological mechanisms underlying myelin loss have yet to be fully characterized, oxidative stress (OS) appears to play a prominent role. Specifically, acrolein, a neurotoxic aldehyde that is both a product and an instigator of OS, has been observed in studies to elicit demyelination through calcium-independent and -dependent mechanisms and also by affecting glutamate uptake and promoting excitotoxicity. Furthermore, pharmacological scavenging of acrolein has demonstrated a neuroprotective effect in animal disease models, by conserving myelin's structural integrity and alleviating functional deficits. This evidence indicates that acrolein may be a key culprit of myelin damage while acrolein scavenging could potentially be a promising therapeutic approach for patients suffering from nervous system trauma and disease.

Acute systemic accumulation of acrolein in mice by inhalation at a concentration similar to that in cigarette smoke

Cigarette smoke is an important environmental factor associated with a wide array of public health concerns. Acrolein, a component of tobacco smoke and a known toxin to various cell types, may be a key pathological factor mediating the adverse effects linked with tobacco smoke. Although acrolein is known to accumulate in the respiratory system after acute nasal exposure, it is not clear if it accumulates systemically, and less is known in the nervous system. The aim of this study was to assess the degree of acrolein accumulation in the circulation and in the spinal cord following acute acrolein inhalation in mice. Using a laboratory-fabricated inhalation chamber, we found elevated urinary 3-HPMA, an acrolein metabolite, and increased acrolein adducts in the spinal cord after weeks of nasal exposure to acrolein at a concentration similar to that in tobacco smoke. The data indicated that acrolein is absorbed into the circulatory system and some enters the nervous system. It is expected that these findings may facilitate further studies to probe the pathological role of acrolein in the nervous system resulting from smoke and other external sources.

Acrolein detection: potential theranostic utility in multiple sclerosis and spinal cord injury

Oxidative stress has been implicated as a major pathological process underlying CNS disease and trauma. More specifically, acrolein, an unsaturated aldehyde, produced by way of lipid peroxidation, has been shown to play a crucial role in initiating and perpetuating detrimental effects associated with multiple sclerosis and spinal cord injury. In light of these findings, quantification of acrolein levels both systemically and locally could allow for the use of acrolein as a biomarker to aid in diagnosis and guide treatment regimens. The three main approaches currently available are acrolein derivatization followed by LC/GC-MS, application of an acrolein antibody and subsequent immunoblotting, and the 3-hydroxypropylmercapturic acid-based method. Of these three strategies, the 3-hydroxypropylmercapturic acid-based method is the least invasive allowing for rapid translation of acrolein detection into a clinical setting.

New insights in the pathogenesis of multiple sclerosis--role of acrolein in neuronal and myelin damage

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) characterized by an inappropriate inflammatory reaction resulting in widespread myelin injury along white matter tracts. Neurological impairment as a result of the disease can be attributed to immune-mediated injury to myelin, axons and mitochondria, but the molecular mechanisms underlying the neuropathy remain incompletely understood. Incomplete mechanistic knowledge hinders the development of therapies capable of alleviating symptoms and slowing disease progression in the long-term. Recently, oxidative stress has been implicated as a key component of neural tissue damage prompting investigation of reactive oxygen species (ROS) scavengers as a potential therapeutic option. Despite the establishment of oxidative stress as a crucial process in MS development and progression, ROS scavengers have had limited success in animal studies which has prompted pursuit of an alternative target capable of curtailing oxidative stress. Acrolein, a toxic β-unsaturated aldehyde capable of initiating and perpetuating oxidative stress, has been suggested as a viable point of intervention to guide the development of new treatments. Sequestering acrolein using an FDA-approved compound, hydralazine, offers neuroprotection resulting in dampened symptom severity and slowed disease progression in experimental autoimmune encephalomyelitis (EAE) mice. These results provide promise for therapeutic development, indicating the possible utility of neutralizing acrolein to preserve and improve neurological function in MS patients.

Determination of urine 3-HPMA, a stable acrolein metabolite in a rat model of spinal cord injury

Acrolein has been suggested to be involved in a variety of pathological conditions. The monitoring of acrolein is of significant importance in delineating the pathogenesis of various diseases. Aimed at overcoming the reactivity and volatility of acrolein, we describe a specific and stable metabolite of acrolein in urine, N-acetyl-S-3-hydroxypropylcysteine (3-HPMA), as a potential surrogate marker for acrolein quantification. Using the LC/MS/MS method, we demonstrated that 3-HPMA was significantly elevated in a dose-dependent manner when acrolein was injected into rats IP or directly into the spinal cord, but not when acrolein scavengers were co-incubated with acrolein solution. A nonlinear mathematic relationship is established between acrolein injected directly into the spinal cord and a correlated dose-dependent increase of 3-HPMA, suggesting the increase of 3-HPMA becomes less apparent as the level of injected acrolein increases. The elevation of 3-HPMA was further detected in the rat spinal cord injury, a pathological condition known to be associated with elevated endogenous acrolein. This finding was further validated by concomitant confirmation of increased acrolein-lysine adducts using established dot immunoblotting techniques. The noninvasive nature of measuring 3-HPMA concentrations in urine allows for long-term monitoring of acrolein in the same animal and ultimately in human clinical studies. Due to wide spread involvement of acrolein in human health, the benefits of this study have the potential to enhance human health significantly.

Medianes management and the individual patient

Focal points

Anti-acrolein treatment improves behavioral outcome and alleviates myelin damage in experimental autoimmune encephalomyelitis mouse

Oxidative stress is considered a major contributor in the pathology of multiple sclerosis (MS). Acrolein, a highly reactive aldehyde byproduct of lipid peroxidation, is thought to perpetuate oxidative stress. In this study, we aimed to determine the role of acrolein in an animal model of MS, experimental autoimmune encephalomyelitis (EAE) mice. We have demonstrated a significant elevation of acrolein protein adduct levels in EAE mouse spinal cord. Hydralazine, a known acrolein scavenger, significantly improved behavioral outcomes and lessened myelin damage in spinal cord. We postulate that acrolein is an important pathological factor and likely a novel therapeutic target in MS.

Differential effects of anesthetics on cocaine's pharmacokinetic and pharmacodynamic effects in brain

Most studies of the effect of cocaine on brain activity in laboratory animals are preformed under anesthesia, which could potentially affect the physiological responses to cocaine. Here we assessed the effects of two commonly used anesthetics [alpha-chloralose (alpha-CHLOR) and isofluorane (ISO)] on the effects of acute cocaine (1 mg/kg i.v.) on cerebral blood flow (CBF), cerebral blood volume (CBV), and tissue hemoglobin oxygenation (S(t)O(2)) using optical techniques and cocaine's pharmacokinetics (PK) and binding in the rat brain using (PET) and [(11)C]cocaine. We showed that acute cocaine at a dose abused by cocaine abusers decreased CBF, CBV and S(t)O(2) in rats anesthetized with ISO, whereas it increased these parameters in rats anesthetized with alpha-CHLOR. Importantly, in ISO-anesthetized animals cocaine-induced changes in CBF and S(t)O(2) were coupled, whereas for alpha-CHLOR these measures were uncoupled. Moreover, the clearance of [(11)C]cocaine from the brain was faster for ISO (peak half-clearance 15.8 +/- 2.8 min) than for alpha-CHLOR (27.5 +/- 0.6 min), and the ratio of specific to non-specific binding of [(11)C]cocaine in the brain was higher for ISO- (3.37 +/- 0.32) than for alpha-CHLOR-anesthetized rats (2.24 +/- 0.4). For both anesthetics, cocaine-induced changes in CBF followed the fast uptake of [(11)C]cocaine in the brain (peaking at approximately 2.5-4 min), but only for ISO did the duration of the CBV and S(t)O(2) changes correspond to the rate of [(11)C]cocaine's clearance from the brain. These results demonstrate that anesthetics influence cocaine's hemodynamic and metabolic changes in the brain, and its binding and PK, which highlights the need to better understand the interactions between anesthetics and pharmacological challenges in brain functional imaging studies.

Quantification of cocaine-induced cortical blood flow changes using laser speckle contrast imaging and Doppler optical coherence tomography

We present a dual-imaging technique combining laser speckle contrast imaging and spectral-domain Doppler optical coherence tomography to enable quantitative characterization of local cerebral blood flow (CBF) changes in rat cortex in response to drug stimulus (e.g., cocaine) at high spatiotemporal resolutions. To examine the utility of this new technique, animal experiments were performed to study the influences of anesthetic regimes (e.g., isoflurane, alpha-chloralose) on the pharmadynamic effects of acute cocaine challenge. The results showed that cocaine-evoked CBF patterns (e.g., increases in alpha-chloralose and decreases in isoflurane regimes) were quantitatively characterized, thus rendering it a potentially useful tool for imaging studies of brain functions.

Development and implementation of an education and credentialing programme to provide safe paediatric procedural sedation in emergency departments

OBJECTIVE

In the conduct of paediatric procedural sedation (PPS) within the ED the combination of powerful drugs, variable competency levels and high staff turnover carry the potential for sedation-associated adverse events. Yet, currently, there is no set programme for education and accreditation of ED staff in PPS. We set out to develop such a programme.

METHODS

We outline the development process of a comprehensive multidisciplinary PPS programme and present its key educational elements (sedation manual, lecture, treatment order form and checklist, parent information handout) and credentialing through multiple-choice questions and competency assessments. We describe issues associated with the implementation of the programme at a metropolitan mixed ED and the ED of a major tertiary paediatric centre.

RESULTS

Since its inception a total of 294 emergency staff have either completed or have partially completed the programme. Staff feedback showed that the majority of staff scored the elements of the programme as very good to excellent, and felt that their sedation skills had improved and their practice was safer. The development and implementation of the PPS programme raised many issues and posed a number of challenges. We describe the strategies we used to overcome such challenges and barriers.

CONCLUSION

We present the development and implementation of a comprehensive PPS programme for emergency staff. As a result of the multicentre development process involving a community and a tertiary paediatric ED the programme will likely have broad applicability in different types of ED caring for children.

Evaluation of the impact of a paediatric procedural sedation credentialing programme on quality of care

OBJECTIVES

The aim of the present study is to describe changes in documentation, risk assessment and patient care resulting from implementation of a credentialing process for medical and nursing staff in paediatric procedural sedation (PPS) in two EDs - one an urban mixed ED and the other a specialist paediatric ED.

METHODS

Chart review of 100 patients undergoing PPS prior to and 100 patients following introduction of the PPS programme. Information was extracted from medical records and sedation checklists. Demographics, drugs used, procedure performed and elements of the pre-procedural, intra-procedural and post-procedural care were compared pre- and post implementation of the PPS programme.

RESULTS

Significant improvements in the post-implementation period compared with pre-implementation were seen in: frequency of documentation of informed consent (87 vs 15%, P < 0.0001); evidence of performance of a pre-procedural risk assessment (87 vs 1%, P < 0.0001); and appropriate recording of vital signs (58 vs 27%, P < 0.0001). Improvements were also noted in documentation of weight, allergies, fasting status and recording of drug orders. There were no adverse events recorded in the pre-programme period and 6 recorded in the post-programme period.

CONCLUSION

The implementation of a PPS credentialing programme into these two EDs resulted in significant improvements in risk assessment, monitoring and documentation of important information related to safe PPS. These improvements should result in improved quality and safety of PPS.

Theta oscillations in human cortex during a working-memory task: evidence for local generators

Cortical theta appears important in sensory processing and memory. Intracanial electrode recordings provide a high spatial resolution method for studying such oscillations during cognitive tasks. Recent work revealed sites at which oscillations in the theta range (4-12 Hz) could be gated by a working-memory task: theta power was increased at task onset and continued until task offset. Using a large data set that has now been collected (10 participants/619 recording sites), we have sufficient sampling to determine how these gated sites are distributed in the cortex and how they are synchronized. A substantial fraction of sites in occipital/parietal (45/157) and temporal (23/280) cortices were gated by the task. Surprisingly, this aspect of working-memory function was virtually absent in frontal cortex (2/182). Coherence measures were used to analyze the synchronization of oscillations. We suspected that because of their coordinate regulation by the working-memory task, gated sites would have synchronized theta oscillations. We found that, whereas nearby gated sites (<20 mm) were often but not always coherent, distant gated sites were almost never coherent. Our results imply that there are local mechanisms for the generation of cortical theta.

Training effects of short bouts of stair climbing on cardiorespiratory fitness, blood lipids, and homocysteine in sedentary young women

OBJECTIVES

To study the training effects of eight weeks of stair climbing on Vo2max, blood lipids, and homocysteine in sedentary, but otherwise healthy young women.

METHODS

Fifteen women (mean (SD) age 18.8 (0.7) years) were randomly assigned to control (n = 7) or stair climbing (n = 8) groups. Stair climbing was progressively increased from one ascent a day in week 1 to five ascents a day in weeks 7 and 8. Training took place five days a week on a public access staircase (199 steps), at a stepping rate of 90 steps a minute. Each ascent took about two minutes to complete. Subjects agreed not to change their diet or lifestyle over the experimental period.

RESULTS

Relative to controls, the stair climbing group displayed a 17.1% increase in Vo2max and a 7.7% reduction in low density lipoprotein cholesterol (p < 0.05) over the training period. No change occurred in total cholesterol, high density lipoprotein cholesterol, triglycerides, or homocysteine.

CONCLUSIONS

The study confirms that accumulating short bouts of stair climbing activity throughout the day can favourably alter important cardiovascular risk factors in previously sedentary young women. Such exercise may be easily incorporated into the working day and therefore should be promoted by public health guidelines.

The impact of information technology on the performance of clinical pharmacy services

Electronic patient records are now being developed to assist in the clinical management of patients within secondary care. This paper reviews how various types of information technology used in these electronic patient records can improve the performance of clinical pharmacy services. The different levels of information technology support for some of the main aspects of clinical pharmacy services are described. How the impact and outcome of information technology support for these services should be evaluated are discussed. The human and technological factors that must be considered to ensure that the implementation succeeds and the potential benefits are realized are examined.

Community-acquired Legionnaires' disease following minimal exposure to a contaminated source

A case of community-acquired Legionnaires' disease (LD) is described. The source of infection was traced to a push-on tap at the end of a long spur from the hot circulation system in a large old residential building which had been unoccupied for several weeks. Legionella pneumophila serogroup 1 subgroup Pontiac was isolated from the patient's sputum and from the contaminated water supply. Isolates were shown to be indistinguishable from one another when subtyped by pulsed field gel electrophoresis of chromosomal DNA.

A memory clinic for the assessment of mild dementia

The aims and experience of work in a specialist memory clinic' are described with reference to the first 200 patients attending the service. 93.5% of attenders were found to suffer from dementia. 67.9% of these fulfilled criteria for probable/possible Alzheimer's disease or other primary degenerative dementias and 8.6% fulfilled criteria for vascular dementia. In the remaining cases the aetiology of the dementia was considered to be multifactorial. The memory clinic proved to be an important resource for demented patients, their carers, and for research projects.

Exclusion of close linkage of bipolar disorder to the dopamine D3 receptor gene in nine Australian pedigrees

The recently cloned dopamine D3 receptor (DRD3) gene is of potential relevance to the aetiology of bipolar disorder because of an almost exclusive expression in limbic tissue, the region of the brain putatively responsible for control of emotion. We therefore aimed to determine whether bipolar disorder in nine pedigrees (with 171 members) was linked to this receptor gene, which has been mapped to chromosomal region 3q 13.3. Linkage of bipolar disorder and recurrent depression to the DRD3 gene was tested using a series of autosomal dominant and recessive models with varying penetrance levels. Additionally, linkage was examined using a series of levels of definitions of affective illness (ranging from bipolar I alone to all affective disorders). Close linkage to the DRD3 gene was strongly excluded using each model and definition, and these conclusions persisted when a wide range of rates of 'sporadic' (non-genetic) presentations of illness were incorporated in the analysis.

Transposon mutagenesis in Legionella pneumophila. II.--Mutants exhibiting impaired intracellular growth within cultured macrophages and reduced virulence in vivo

Transposon Tn5 mutants of L. pneumophila were isolated and screened for loss of virulence-associated characteristics. Three mutants were found with normal ability to produce putative pathogenicity determinants and to be endocytosed by guinea pig alveolar macrophages in vitro but with a greatly reduced ability to multiply within them. These mutants showed considerable loss of virulence in an authentic animal model of the pneumonia.

Transposon mutagenesis in Legionella pneumophila. I.--Persistence of suicide and broad host-range plasmids

Two of three highly virulent strains of Legionella pneumophila could act as recipients at high frequencies in conjugation experiments with Escherichia coli donor strains carrying broad host-range plasmids belonging to incompatibility groups N, P and W. All broad host-range and most transposon-delivery plasmids persisted within transconjugants with high stability. Only one (pSUP1021) of several vehicles designed for the delivery of transposons into the chromosome of Gram-negative bacteria was found to yield transposon mutants of Legionella at a detectable frequency.

Exclusion of close linkage of bipolar disorder to dopamine D1 and D2 receptor gene markers

A potential role of dopamine in bipolar disorder has been suggested by several strands of evidence, namely the ability of dopaminergic agonists to induce mania and the effects of lithium, carbamazepine and the antipsychotics on central dopamine receptors and/or turnover. We therefore aimed to determine if bipolar disorder in two large bipolar pedigrees was linked to the recently cloned dopamine D1 (DRD1) and D2 (DRD2) receptors. (These have been mapped to chromosomal regions 5q35.1 and 11q22.3-q23, respectively). Linkage of bipolar disorder and recurrent depression to DRD1 and DRD2 was tested using a series of genetic models with varying penetrance levels. Additionally, linkage was examined using a series of levels of definitions of affective status (ranging from bipolar I alone to all affective illnesses). Close linkage to these markers was strongly excluded using each model and definition. The findings for DRD1 also persisted when a wide range of rates of 'sporadic' (non-genetic) presentations of illness were incorporated in the analysis, but the DRD2 results did not remain statistically significant at high sporadic rates. The exclusion of linkage to DRD2 is consistent with other recent reports.

Extending community health nursing services. The Student Learning Center

Faced with scarce resources, the Visiting Nurse Association of Omaha (VNA), Bishop Clarkson College, Creighton University, and University of Nebraska Medical Center collaborated to maintain services. Baccalaureate students learned to deliver community health nursing while serving a population in need of these services, but not coverable by funding sources. The Student Learning Center established by the VNA enabled 254 students to provide 5,035 home visits to families without funding sources.

A plasmid from a virulent strain of Legionella pneumophila is conjugative and confers resistance to ultraviolet light

The presence of a single apparently cryptic plasmid of approximately 36 MDa was demonstrated in the virulent Dodge strain of Legionella pneumophila. 'Tagging' of the plasmid with Tn5 enabled transfer to be demonstrated to other strains of Legionella (though not to Escherichia coli or Pseudomonas aeruginosa) as well as a definitive assessment to be made of its stability. Plasmid carriage confers resistance to UV light probably by means of an error-prone UV repair system. The plasmid is compatible with plasmids of the IncP and IncW incompatibility groups.

Development after exposure to polychlorinated biphenyls and dichlorodiphenyl dichloroethene transplacentally and through human milk

OBJECTIVE

To determine whether exposure to polychlorinated biphenyls (PCBs) or dichlorodiphenyl dichloroethene (DDE), either transplacentally or through breast feeding, affected scores on the Bayley Scales of Infant Development at 6 or 12 months of age.

DESIGN

Cohort followed from birth to 1 year of age.

SETTING

General community.

PARTICIPANTS

Volunteer sample of 858 infants, of whom 802 had Bayley scores available at either 6 months or 12 months or both.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Bayley scales and chemical measurements were done independently. Higher transplacental exposure to PCBs was associated with lower psychomotor scores at both 6 and 12 months of age; the difference between the mean scores in the lowest and highest PCB groups was 7 points at 6 months and 8 points at 12 months. Higher transplacental exposure to DDE was associated with higher mental scores at 6 months of age (the difference between the mean scores in the lowest and highest DDE groups was 6 points), but no relationship was seen at 12 months. Exposure to either chemical through breast feeding was apparently unrelated to Bayley scores.

CONCLUSIONS

Transplacental exposure to PCBs was associated with lower psychomotor scores. No deleterious effects were associated with breast feeding.

Polychlorinated biphenyls (PCBs) and dichlorodiphenyl dichloroethene (DDE) in human milk: effects on growth, morbidity, and duration of lactation

We followed 858 children from birth to one year of age to determine whether the presence of polychlorinated biphenyls (PCBs) and dichlorodiphenyl dichloroethene (DDE) in breast milk affected their growth or health. Neither chemical showed an adverse effect on weight or frequency of physician visits for various illnesses, although differences were seen between breast-fed and bottle-fed children, with bottle-fed children being heavier and having more frequent gastroenteritis and otitis media. Children of mothers with higher levels of DDE were breast-fed for markedly shorter times, but adjustments for possible confounders and biases did not change the findings. In absence of any apparent effect on the health of the children, we speculate that DDE may be interfering with the mother's ability to lactate, possibly because of its estrogenic properties.

Neonatal effects of transplacental exposure to PCBs and DDE

Neonatal effects of transplacental exposure to polychlorinated biphenyls (PCBs) and dichlorodiphenyl dichloroethene (DDE) were examined in a study of 912 infants. Birth weight, head circumference, and neonatal jaundice showed no relationship to PCBs or DDE. We also administered the Brazelton Neonatal Behavioral Assessment Scales, which are psychologic and neurologic tests designed for use in newborn infants. The results of these tests showed that higher PCB levels were associated with hypotonicity and hyporeflexia and that higher DDE levels were associated with hyporeflexia.

Polychlorinated biphenyls (PCBs) and dichlorodiphenyl dichloroethene (DDE) in human milk: effects of maternal factors and previous lactation

The authors measured polychlorinated biphenyls (PCBs) and dichlorodiphenyl dichloroethene (DDE) in maternal serum, cord blood, placenta, and serial samples of breast milk from 868 women. Almost all samples of breast milk showed detectable levels of both chemicals. Overall, values for DDE in this study are within the range of those found previously, whereas those for PCBs are somewhat higher. Possible causes of variation in levels were investigated. For DDE, older women, Black women, cigarette smokers, and women who consumed sport fish during pregnancy had higher levels; only age and race showed large effects. For PCBs, older women, women who regularly drink alcohol, and primiparae had higher levels. In addition, both chemicals showed modest variation across occupational groupings. Casual exposure to a PCB spill did not result in chemical levels different from background. In general, women have higher levels in their first lactation and in the earlier samples of a given lactation, and levels decline both with time spent breast-feeding and with number of children nursed. These striking declines are presumably a measure of exposure to the child.

Protection of phenylalanine ammonia-lyase from proteolytic attack

Phenylalanine ammonia-lyase contained within permeabilized cells of Rhodosporidium toruloides was protected from proteolytic attack by trypsin, chymotrypsin and duodenal juice. The inactivation by the proteases was biphasic. The enzyme contained within the yeast cells had a similar Km for phenylalanine and Ki for cinnamic acid to the protein in free solution. Phenylalanine ammonia-lyase present in the yeast depleted duodenal juice of free phenylalanine, while the enzyme in free solution did not. The possibility of using permeabilized cells of R. toruloides as a vehicle for protecting orally ingested therapeutic enzymes from proteolytic inactivation is discussed.

Transformation of Rhodosporidium toruloides

Rhodosporidium toruloides protoplasts could be transformed, in the presence of polyethylene glycol (PEG), at frequencies of approx. 1 X 10(3) transformants/micrograms of DNA. The plasmid used, pHG2, which contains the phenylalanine ammonia-lyase (PAL)-coding gene (PAL) of R. toruloides, could replicate as an unstable plasmid in the yeast, or could integrate at the PAL locus to give stable transformants. Plasmids that function in R. toruloides were constructed using either the PAL gene or LEU2 gene of Saccharomyces cerevisiae as dominant selectable markers. R. toruloides transformed with pHG8, which contains both genes, coinherited the two markers. It is also shown that the 2mu replicon of S. cerevisiae does not function in R. toruloides; neither is the PAL gene expressed in S. cerevisiae.