Consistency and inconsistency in network meta-analysis: concepts and models for multi-arm studies

Meta-analyses that simultaneously compare multiple treatments (usually referred to as network meta-analyses or mixed treatment comparisons) are becoming increasingly common. An important component of a network meta-analysis is an assessment of the extent to which different sources of evidence are compatible, both substantively and statistically. A simple indirect comparison may be confounded if the studies involving one of the treatments of interest are fundamentally different from the studies involving the other treatment of interest. Here, we discuss methods for addressing inconsistency of evidence from comparative studies of different treatments. We define and review basic concepts of heterogeneity and inconsistency, and attempt to introduce a distinction between ‘loop inconsistency’ and ‘design inconsistency’. We then propose that the notion of design-by-treatment interaction provides a useful general framework for investigating inconsistency. In particular, using design-by-treatment interactions successfully addresses complications that arise from the presence of multi-arm trials in an evidence network. We show how the inconsistency model proposed by Lu and Ades is a restricted version of our full design-by-treatment interaction model and that there may be several distinct Lu–Ades models for any particular data set. We introduce novel graphical methods for depicting networks of evidence, clearly depicting multi-arm trials and illustrating where there is potential for inconsistency to arise. We apply various inconsistency models to data from trials of different comparisons among four smoking cessation interventions and show that models seeking to address loop inconsistency alone can run into problems. Copyright © 2012 John Wiley & Sons, Ltd.

Comparative genomics of Listeria species

Listeria monocytogenes is a food-borne pathogen with a high mortality rate that has also emerged as a paradigm for intracellular parasitism. We present and compare the genome sequences of L. monocytogenes (2,944,528 base pairs) and a nonpathogenic species, L. innocua (3,011,209 base pairs). We found a large number of predicted genes encoding surface and secreted proteins, transporters, and transcriptional regulators, consistent with the ability of both species to adapt to diverse environments. The presence of 270 L. monocytogenes and 149 L. innocua strain-specific genes (clustered in 100 and 63 islets, respectively) suggests that virulence in Listeria results from multiple gene acquisition and deletion events.

Ionization and phase behavior of fatty acids in water: application of the Gibbs phase rule

The phase behavior of several medium-chain (10- and 12-carbon) and long-chain (18-carbon) fatty acids in water was examined as a function of the ionization state of the carboxyl group. Equilibrium titration curves were generated above and below fatty acid and acid-soap chain melting temperatures and critical micelle concentrations, and the phases formed were characterized by X-ray diffraction, 13C NMR spectroscopy, and phase-contrast and polarized light microscopy. The resulting titration curves were divided into five regions: (i) at pH values less than 7, a two-phase region containing oil or fatty acid crystals and an aqueous phase; (ii) at pH approximately 7, a three-phase region containing oil, lamellar, and aqueous (or fatty acid crystals, 1:1 acid-soap crystals, and aqueous) phases; (iii) between pH 7 and 9, a two-phase region containing a lamellar fatty acid/soap (or crystalline 1:1 acid-soap) phase in an aqueous phase; (iv) at pH approximately 9, a three-phase region containing lamellar fatty acid-soap (or crystalline 1:1 acid-soap), micellar, and aqueous phases; and (v) at pH values greater than 9, a two-phase region containing micellar and aqueous phases. Interpretation of the results using the Gibbs phase rule indicated that, for oleic acid/potassium oleate, the composition of the lamellar fatty acid/soap phase varied from approximately 1:1 to 1:3 un-ionized to ionized fatty acid species. In addition, constant pH regions observed in titration curves were a result of thermodynamic invariance (zero degrees of freedom) rather than buffering capacity. The results provide insights into the physical states of fatty acids in biological systems.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of teacher attention on study behavior

The effects of contingent teacher attention on study behavior were investigated. Individual rates of study were recorded for one first-grade and five third-grade pupils who had high rates of disruptive or dawdling behavior. A reinforcement period (in which teacher attention followed study behavior and non-study behaviors were ignored) resulted in sharply increased study rates. A brief reversal of the contingency (attention occurred only after periods of non-study behavior) again produced low rates of study. Reinstatement of teacher attention as reinforcement for study once again markedly increased study behavior. Follow-up observations indicated that the higher study rates were maintained after the formal program terminated.

Zebrafish genetic map with 2000 microsatellite markers

The zebrafish is the first vertebrate organism used for large-scale genetic screens seeking genes critical to development. These screens have been quite successful, with more than 1800 recessive mutations discovered that speak to morphogenesis of the vertebrate embryo. The cloning of the mutant genes depends on a dense genetic map. The 2000 markers we present here, using microsatellite (CA) repeats, provides 1.2-cM average resolution. One centimorgan in zebrafish is about 0. 74 megabase, so, for many mutations, these markers are close enough to begin positional cloning by YAC walks.

Randomised controlled trial of exercise for low back pain: clinical outcomes, costs, and preferences

OBJECTIVE

To evaluate effectiveness of an exercise programme in a community setting for patients with low back pain to encourage a return to normal activities.

DESIGN

Randomised controlled trial of progressive exercise programme compared with usual primary care management. Patients' preferences for type of management were elicited independently of randomisation.

PARTICIPANTS

187 patients aged 18-60 years with mechanical low back pain of 4 weeks to 6 months' duration.

INTERVENTIONS

Exercise classes led by a physiotherapist that included strengthening exercises for all main muscle groups, stretching exercises, relaxation session, and brief education on back care. A cognitive-behavioural approach was used.

MAIN OUTCOME MEASURES

Assessments of debilitating effects of back pain before and after intervention and at 6 months and 1 year later. Measures included Roland disability questionnaire, Aberdeen back pain scale, pain diaries, and use of healthcare services.

RESULTS

At 6 weeks after randomisation, the intervention group improved marginally more than the control group on the disability questionnaire and reported less distressing pain. At 6 months and 1 year, the intervention group showed significantly greater improvement in the disability questionnaire score (mean difference in changes 1.35, 95% confidence interval 0.13 to 2.57). At 1 year, the intervention group also showed significantly greater improvement in the Aberdeen back pain scale (4.44, 1.01 to 7.87) and reported only 378 days off work compared with 607 in the control group. The intervention group used fewer healthcare resources. Outcome was not influenced by patients' preferences.

CONCLUSIONS

The exercise class was more clinically effective than traditional general practitioner management, regardless of patient preference, and was cost effective.

The fasciated ear2 gene encodes a leucine-rich repeat receptor-like protein that regulates shoot meristem proliferation in maize

The ability to initiate organs throughout the lifecycle is a unique feature of plant development that is executed by groups of stem cells called meristems. The balance between stem cell proliferation and organ initiation is carefully regulated and ensures that organs can be initiated in regular geometric patterns. To understand how this regulation is achieved, we isolated a novel mutant of maize, fasciated ear2 (fea2), which causes a massive overproliferation of the ear inflorescence meristem and a more modest effect on floral meristem size and organ number. We cloned the fea2 gene using transposon tagging, and it encodes a membrane localized leucine-rich repeat receptor-like protein that is most closely related to CLAVATA2 from Arabidopsis. These findings provide evidence that the CLAVATA pathway for regulation of meristem size is functionally conserved throughout the angiosperms. A possible connection of fea2 to the control of crop yields is discussed.

Who would want to be a nurse? Violence in the workplace--a factor in recruitment and retention

In a climate of a declining nursing workforce where violence and hostility is a part of the day-to-day lives of most nurses, it is timely to name violence as a major factor in the recruitment and retention of registered nurses in the health system. Workplace violence takes many forms such as aggression, harassment, bullying, intimidation and assault. Violent acts are perpetrated against nurses from various quarters including patients, relatives, other nurses and other professional groups. Research suggests that nurse managers are implicated in workplace violence and bullying. Furthermore, there may be a direct link between episodes of violence and aggression towards nurses and sick leave, burnout and poor recruitment and retention rates. This paper explores what is known about workplace violence as it affects nurses, and calls for managerial support and policy to act to improve work environments for all nurses.

Occurrence of hemophilia in the United States. The Hemophilia Surveillance System Project Investigators

An active surveillance system was used to identify all residents with hemophilia in six U.S. states (Colorado, Georgia, Louisiana, Massachusetts, New York, and Oklahoma). A hemophilia case was defined as a person with physician-diagnosed hemophilia A or B and/or a measured baseline factor VIII or IX activity (FA) of 30% or less. Case-finding methods included patient reports from physicians, clinical laboratories, hospitals, and hemophilia treatment centers. Once identified, trained data abstractors collected clinical and outcome data retrospectively from medical records. Among cases identified in 1993-1995, 2,743 were residents of the six states in 1994, of whom 2,156 (79%) had hemophilia A. Of those with available FA measurements, 1,140 (43%) had severe (FA < 1%), 684 (26%) had moderate (FA 1%-5%), and 848 (31%) had mild (FA 6%-30%) disease. The mean and median age was 25.4 and 23 years, respectively. The age-adjusted prevalence of hemophilia in all six states in 1994 was 13.4 cases/100,000 males (10.5 for hemophilia A and 2.9 for B). The prevalence by race/ethnicity was 13.2 cases/100,000 among white, 11.0 among African American, and 11.5 among Hispanic males. Application of age-specific prevalence rates from the six surveillance states to the U.S. population resulted in an estimated national population of 13,320 cases of hemophilia A and 3,640 cases of hemophilia B. For the 10-year period 1982-1991, the average incidence of hemophilia A and B in the hemophilia surveillance system (HSS) states was estimated to be 1 in 5,032 live male births.

Component Analysis versus Common Factor Analysis: Some issues in Selecting an Appropriate Procedure

Should one do a component analysis or a factor analysis? The choice is not obvious, because the two broad classes of procedures serve a similar purpose, and share many important mathematical characteristics. Despite many textbooks describing common factor analysis as the preferred procedure, principal component analysis has been the most widely applied. Here we summarize relevant information for the prospective factor/component analyst. First, we discuss the key algebraic similarities and differences. Next, we analyze a number of theoretical and practical issues. The more practical aspects include: the degree of numeric similarity between solutions from the two methods, some common rules for the number of factors to be retained, effects resulting from overextraction, problems with improper solutions, and comparisons in computational efficiency. Finally, we review some broader theoretical issues: the factor indeterminacy issue, the differences between exploratory and confirmatory procedures, and the issue of latent versus manifest variables.

Magnetic resonance contrast enhancement of neovasculature with alpha(v)beta(3)-targeted nanoparticles

Site-directed contrast enhancement of angiogenic vessels in vivo was demonstrated using antibody targeting of an MRI contrast agent to the alpha(v)beta(3) integrin, a molecular marker characteristic of angiogenic endothelium. The agent was tested in a rabbit corneal micropocket model, in which neovasculature is induced in the cornea using basic fibroblast growth factor. The targeted contrast agent consists of Gd-perfluorocarbon nanoparticles linked to alpha(v)beta(3) integrin antibody DM101. The animal group receiving the targeted contrast agent displayed a 25% increase in the average MR signal intensity after 90 min. Control groups in which the nanoparticles are either used alone, linked to an isotype-matched antibody, or linked to DM101 and administered following receptor blocking did not display MR contrast enhancement at similar dose levels. These findings indicate that the antibody-targeted agent enhances MR signal intensity in the capillary bed in a corneal micropocket model of angiogenesis, and is selectively retained within the angiogenic region via specific interaction with the alpha(v)beta(3) epitope.

A randomized trial of group outpatient visits for chronically ill older HMO members: the Cooperative Health Care Clinic

OBJECTIVE

To compare the impact of group outpatient visits to traditional "physician-patient dyad" care among older chronically ill HMO members on health services utilization and cost, self-reported health status, and patient and physician satisfaction.

DESIGN

A 1-year randomized trial.

SETTING

A group model HMO in the Denver Metropolitan area.

PARTICIPANTS

Three hundred twenty-one members aged 65 and older, randomized to a group visit intervention (n = 160) or to usual care (n = 161).

INTERVENTION

Patients with high health services utilization and one or more chronic conditions had monthly group visits with their primary care physician and nurse. Visits included health education, prevention measures, opportunities for socialization, mutual support, and for one-to-one consultations with their physician, where necessary.

MEASUREMENTS

Health services utilization and associated cost, health status, and patient and physician satisfaction.

RESULTS

Outcome measures obtained after a 1-year follow-up period showed that group participants had fewer emergency room visits (P = .009), visits to subspecialists (P = .028), and repeat hospital admissions per patient (P = .051). Group participants made more visits (P = .021) and calls (P = .038) to nurses than control group patients and fewer calls to physicians (P = .019). In addition, a greater percentage of group participants received influenza and pneumonia vaccinations (P < .001). Group participants had greater overall satisfaction with care (P = .019), and participating physicians reported higher levels of satisfaction with the groups than with individual care. No differences were observed between groups on self-reported health and functional status. Cost of care per member per month was $14.79 less for the group participants.

CONCLUSIONS

Group visits for chronically ill patients reduce repeat hospital admissions and emergency care use, reduce cost of care, deliver certain preventive services more effectively, and increase patient and physician satisfaction.

Chronic parenting stress: Moderating versus mediating effects of social support

The present study contrasted the widely cited "buffer" model of social support with an alternative mediator model. Distinctions were drawn between the functions of social support under chronic vs. acute stress conditions, and between situation-specific stressors and major life events. Ongoing parenting stress was assessed in 96 mothers of deaf children and 118 matched controls. Tests of the competing models showed no moderating effects for social support. However, path analyses suggested that social support mediated the relationship between stressors and outcomes. Chronic parenting stress was associated with lowered perceptions of emotional support, and greater symptoms of depression and anxiety. Furthermore, parenting stress accounted for a substantial proportion of the variance in psychological distress scores in contrast to life event stress, which was only weakly related to psychological outcomes. The implications of mediational models for understanding adaptation to chronic stress are discussed.

Salmon lice--impact on wild salmonids and salmon aquaculture

Salmon lice, Lepeophtheirus salmonis, are naturally occurring parasites of salmon in sea water. Intensive salmon farming provides better conditions for parasite growth and transmission compared with natural conditions, creating problems for both the salmon farming industry and, under certain conditions, wild salmonids. Salmon lice originating from farms negatively impact wild stocks of salmonids, although the extent of the impact is a matter of debate. Estimates from Ireland and Norway indicate an odds ratio of 1.1:1-1.2:1 for sea lice treated Atlantic salmon smolt to survive sea migration compared to untreated smolts. This is considered to have a moderate population regulatory effect. The development of resistance against drugs most commonly used to treat salmon lice is a serious concern for both wild and farmed fish. Several large initiatives have been taken to encourage the development of new strategies, such as vaccines and novel drugs, for the treatment or removal of salmon lice from farmed fish. The newly sequenced salmon louse genome will be an important tool in this work. The use of cleaner fish has emerged as a robust method for controlling salmon lice, and aquaculture production of wrasse is important towards this aim. Salmon lice have large economic consequences for the salmon industry, both as direct costs for the prevention and treatment, but also indirectly through negative public opinion.

What is beyond the big five? Plenty!

In a recent analysis of personality data, Saucier and Goldberg (1998) sought to answer the question, What is beyond the Big Five? Those authors evaluated numerous clusters of English person-descriptive adjectives that have been suspected of referring to non-Big Five dimensions of personality. Their results led them to conclude that most, if not all, traits of personality can be adequately subsumed within the Big Five factor space. In contrast, our reanalysis of Saucier and Goldberg's own data, using a more realistic criterion for deciding on whether a variable does or does not fall within a particular factor space, contradicts their claim. We are led to the conclusion that there are plenty of dimensions of behavior beyond the Big Five.

Functional significance of the mu rhythm of human cortex: an electrophysiologic study with subdural electrodes

The existence of the mu rhythm and its general anatomical and physiological relationships are well known. There are few data, however, regarding the details of its anatomical and physiological specificity. We implanted fronto-temporal subdural electrode grids in 9 patients with intractable epilepsy to facilitate their surgical management. A 7-11 Hz cortical mu rhythm was observed in 5-16 electrodes located over the sensorimotor cortex as mapped by electrical stimulation. The mu rhythm was blocked by contralateral face and arm movements, passive movements of contralateral arm, and by ipsilateral arm movements. There was correspondence between the body area movement of which blocked the mu at a given site and the body region that was affected by stimulation at the same site. Power spectral analysis showed an overall decrease in power in all frequency bands. This was less prominent in the 14-100 Hz band resulting in a relative increase in high frequency power in association with movement. We conclude that both the presence and blocking of mu rhythm are specific to the somatic representation of the cortex from which it is recorded. Its functional significance may be similar to other sensory rhythms like the occipital alpha rhythm.

Stimulation and inhibition of angiogenesis by placental proliferin and proliferin-related protein

In many mammalian species, the placenta is the site of synthesis of proteins in the prolactin and growth hormone family. Analysis of two such proteins, proliferin (PLF) and proliferin-related protein (PRP), revealed that they are potent regulators of angiogenesis; PLF stimulated and PRP inhibited endothelial cell migration in cell culture and neovascularization in vivo. The mouse placenta secretes an angiogenic activity during the middle of pregnancy that corresponds primarily to PLF, but later in gestation releases a factor that inhibits angiogenesis, which was identified as PRP. Incubation of placental tissue with PLF led to the specific binding of this hormone to capillary endothelial cells. Thus PLF and PRP may regulate the initiation and then the cessation of placental neovascularization.

Strain features and distributions in pneumococci from children with invasive disease before and after 13-valent conjugate vaccine implementation in the USA

The effect of second-generation pneumococcal conjugate vaccines on invasive pneumococcal disease (IPD) strain distributions have not yet been well described. We analysed IPD isolates recovered from children aged <5 years through Active Bacterial Core surveillance before (2008–2009; n = 828) and after (2011–2013; n = 600) 13-valent pneumococcal conjugate vaccine (PCV13) implementation. We employed conventional testing, PCR/electrospray ionization mass spectrometry and whole genome sequence (WGS) analysis to identify serotypes, resistance features, genotypes, and pilus types. PCV13, licensed in February 2010, effectively targeted all major 19A and 7F genotypes, and decreased antimicrobial resistance, primarily owing to removal of the 19A/ST320 complex. The strain complex contributing most to the remaining β-lactam resistance during 2011–2013 was 35B/ST558. Significant emergence of non-vaccine clonal complexes was not evident. Because of the removal of vaccine serotype strains, positivity for one or both pilus types (PI-1 and PI-2) decreased in the post-PCV13 years 2011–2013 relative to 2008–2009 (decreases of 32–55% for PI-1, and >95% for PI-2 and combined PI-1 + PI-2). β-Lactam susceptibility phenotypes correlated consistently with transpeptidase region sequence combinations of the three major penicillin-binding proteins (PBPs) determined through WGS analysis. Other major resistance features were predictable by DNA signatures from WGS analysis. Multilocus sequence data combined with PBP combinations identified progeny, serotype donors and recipient strains in serotype switch events. PCV13 decreased the frequency of all PCV13 serotype clones and concurrently decreased the frequency of strain subsets with resistance and/or adherence features conducive to successful carriage. Our results serve as a reference describing key features of current paediatric IPD strains in the USA after PCV13 implementation.

Factorial structure of traits delineating personality disorders in clinical and general population samples

Categorical and dimensional models for classifying personality disorders were evaluated by comparing the structure of personality pathology in a clinical sample (n = 158) with the structure in a general population sample (n = 274). Subjects completed 100 personality scales. Separate factor analyses revealed similar structures in the 2 samples. An underlying structure in a combined sample showed limited agreement with the concepts of the Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, 1987). Fifteen factors were retained: Generalized Distress, Rejection, Restricted Expression, Compulsivity, Stimulus Seeking, Insecure Attachment, Diffidence, Intimacy Problems, Oppositionality, Interpersonal Disesteem, Conduct Problems, Cognitive Dysfunction, Affective Reactivity, Narcissism, and Social Apprehensiveness. The results are consistent with a dimensional representation of personality disorder.

Subsensitivity to dopaminergic drugs in periadolescent rats: a behavioral and neurochemical analysis

It has been reported that post-natal day (PD) 30-40 rats respond differently to the behavioral effects of dopaminergic drugs when compared to younger or older rats. In this study, the behavioral effects of amphetamine (AMPH) on motor behavior and the effects of dopaminergic drugs on striatal acetylcholine (ACh) release were evaluated in periadolescent (PD35) and adult rats. AMPH increased dopamine (DA)-mediated motor behaviors (locomotor activity and stereotypy) in periadolescent and adult rats; however, these responses were of a lesser magnitude in periadolescent rats. In adult rats, cocaine and nomifensine inhibited ACh overflow in a dose-dependent manner. In periadolescent rats, ACh overflow was maximally inhibited at a lower drug concentration (5 microM) than in adult rats (10 microM) signifying increased sensitivity in these rats. Apomorphine inhibited ACh overflow in a dose-dependent fashion in slices from adult rats. In contrast, apomorphine did not consistently inhibit ACh overflow in striatal slices prepared from periadolescent rats. Collectively, the results of this study demonstrate behavioral subsensitivity to AMPH in periadolescent rats. Examination of the effects of DA reuptake blockers on DA modulation of striatal cholinergic neurons failed to reveal a corresponding subsensitivity. In fact, ACh release was more sensitive to DA reuptake blockers in periadolescent rats. This latter finding suggests that undisclosed factors override dopaminergic modulation of striatal neurons in the mediation of behavior in periadolescent rats. We propose that during periadolescence, DA transmission is transiently elevated. This results in post-synaptic supersensitivity of cholinergic receptors and consequently induces behavioral subsensitivity when challenged with dopaminergic drugs. Increased cholinergic tone may mediate behavioral subsensitivity despite drug-induced elevations in DA.

Duplex ultrasound and contrast-enhanced ultrasound versus computed tomography for the detection of endoleak after EVAR: systematic review and bivariate meta-analysis

INTRODUCTION

Contrast-enhanced computed tomography (CT) has become the 'gold-standard' imaging modality for surveillance following EVAR. However repeated CT causes cumulative contrast related renal injury. Duplex ultrasound (USS) and contrast-enhanced (non-nephrotoxic) duplex scanning (CEUS) are less invasive but considered less accurate than CT. The aim of this study was to determine the diagnostic accuracy of imaging modalities used to detect endoleak. Accordingly, we undertook a systematic review and meta-analysis of the evidence base for USS and CEUS compared to CT following EVAR.

METHODS

Medline, Embase, trial registries, conference proceedings and article reference lists were searched to identify trials comparing USS or CEUS with CT following EVAR. Contrast-enhanced computed tomography was taken as the 'gold-standard' investigation. USS and CEUS were compared to CT in separate meta-analyses.

RESULTS

Twenty-one studies in 2601 patients compared USS with CT. The sensitivity of USS at detecting endoleak was 0.77 (95% CI 0.64-0.86; I(2)=0.82) and pooled specificity 0.94 (95% CI 0.88-0.97; I(2)=0.90). Seven studies (288 patients) compared CEUS vs CT. The pooled sensitivity was 0.98 (95% CI 0.90-0.99; I(2)=0.32) and specificity 0.88 (95% CI 0.78-0.94; I(2)=0.67).

CONCLUSION

This study confirms that unenhanced USS has poor sensitivity for endoleak detection; however CEUS is a highly sensitive modality. These results should be interpreted with some caution due to heterogeneity in analysed trials and further research is needed to evaluate the efficacy of CEUS before it can be utilised as the primary imaging modality for EVAR surveillance.

Neural tumors of the oral cavity. A review of the spectrum of benign and malignant oral tumors of the oral cavity and jaws

The clinical and histologic features of benign and malignant neural tumors of the oral cavity and jaws are reviewed. Some rarer histologic variants are mentioned. Particular attention is paid to the two syndromes involving neural tumors of the oral cavity, namely, neurofibromatosis and multiple endocrine neoplasia III. A previously unreported case of the latter is presented.

Inverted repeat structure of the Sry locus in mice

The testis-determining gene Sry is located on the short arm of the mouse Y chromosome in a region known to have undergone duplications and rearrangements in comparison with the equivalent portion of the human Y chromosome. Detailed analysis of the Sry genomic locus reveals a further difference in that the mouse Sry open reading frame lies within 2.8 kilobases of unique sequence at the center of a large inverted repeat. This repeat, which is found in both Mus musculus musculus and Mus musculus domesticus Y chromosomes, is not present at the human SRY locus. Recombination involving the repeat region may have led to an 11-kilobase deletion, precisely excising Sry in a line of XY female mice.

Childhood lead poisoning. A controlled trial of the effect of dust-control measures on blood lead levels

Lead-contaminated house dust is one factor in childhood lead poisoning; however, most lead-reduction programs do not emphasize the control of house dust. We studied whether lead-reduction plus dust-control measures would lower blood lead levels in children with Class II or III poisoning (blood lead levels, 30 to 49 micrograms per deciliter) more effectively than lead reduction alone. An experimental group of 14 children and a control group of 35 children whose homes had already been treated were studied. In experimental homes, sites with elevated lead levels (greater than 100 micrograms per 930 cm2) were wet-mopped twice monthly and families were encouraged to clean and to wash the child's hands frequently. After one year blood lead levels fell an average of 6.9 micrograms per deciliter in the experimental group, as compared with 0.7 micrograms per deciliter in controls (P less than 0.001). Children in the experimental group with the highest blood lead levels had the most marked reduction. Four children in the control group (and none in the experimental group) required chelation therapy for blood levels greater than 50 micrograms per deciliter. These results show that a focused dust-control program can reduce blood lead levels more than standard lead removal in the home.

Categorical distinctions in the study of personality disorder: implications for classification

This article discusses the historical underpinnings of psychiatric classification and examines empirical evidence relevant to (a) whether personality disorders are distinct from each other and from normal personality and (b) whether personality disorders should be classified separately from other mental disorders. At the phenotypic level, research evidence strongly supports the use of a dimensional model to delineate personality disorders; evidence about their genotypic representation is less conclusive though still supportive. Neither empirical nor rational arguments indicate strong justification for separating personality disorders from other mental disorders, as has been done in both the third and fourth editions of the Diagnostic and Statistical Manual of Mental Disorders. Distinctions between abnormal and disordered personality are considered, and suggestions are made for more satisfactory diagnostic classificatory schemes.