Two-year-olds will name artifacts by their functions

Do young children take functional information into account in naming artifacts? In three studies of lexical categorization, 112 children 2 years of age learned new names for novel artifacts with novel functions and then extended the names to new objects. The objects were designed to have functions that were causally related in simple and compelling ways to perceptible aspects of their physical structure. Despite only minimal opportunity to familiarize themselves with the objects, children generalized the names in accordance with the objects' functions. This result obtained even when children had to discover the functions of the named objects on their own (Experiment 2) and when all the test objects had some discernible function (Experiment 3). Two-year-olds name by function when they can make sense of the relation between the appearances and the functions of artifacts.

Proficiency-testing issues relating to sirolimus

BACKGROUND

A need exists to document laboratory proficiency to (1) compare results produced by different analytical techniques and (2) ensure consistency of results from multiple testing sites.

OBJECTIVES

To enable concentration-controlled studies of sirolimus to proceed with confidence, proficiency-testing schemes were put in place at laboratories selected to act as reference laboratories. The feasibility of establishing an ongoing proficiency-testing scheme was addressed with respect to sample stability. The scheme was then used to test proficiency for the measurement of sirolimus in 3 blinded samples each month.

METHODS

The method chosen for measurement of sirolimus was a prototype microparticle enzyme immunoassay. Initially, 15 laboratories were asked to analyze a series of 85 blinded samples that tested their inaccuracy, repeatability, and reproducibility for the measurement and their ability to dilute over-range samples competently. Both blood samples spiked with sirolimus and pooled blood samples from patients receiving the drug were circulated to a maximum of 50 laboratories.

RESULTS

Overall, both inaccuracy and imprecision were acceptable by predefined criteria. Inaccuracy for the immunoassay (percentage difference of the measured value against the nominal value) averaged -5% (95% CI, -9% to -1%). The mean percentage difference between the immunoassay and a high-performance liquid chromatographic assay with mass-spectrometric detection for the measurement of sirolimus in pooled samples (n = 5) from patients receiving the drug was 29% (95% CI, 24% to 34%).

CONCLUSION

The techniques documented here as part of the International Sirolimus Proficiency Testing Scheme could be applied to other clinical studies requiring protocol-driven dosing adjustments based on sirolimus measurements, irrespective of analytical technique used.

An immunoassay for the measurement of sirolimus

OBJECTIVE

This study assessed the performance characteristics of a new microparticle enzyme immunoassay (MEIA) for the determination of sirolimus in whole blood.

BACKGROUND

In clinical investigatory studies, dose adjustments of the immunosuppressive drug sirolimus have been carried out using either high-performance liquid chromatography (HPLC) or, more recently, this investigational immunoassay kit based on the MEIA technique.

METHODS

Calibration was made over the linear range 0 to 30 ng/mL. Inaccuracy and imprecision were assessed by means of 3 control samples supplied with the kit (5, 11, and 22 ng/mL) and dilution of an above-quantitation-limit sample (154 ng/mL). Specificity was determined by the addition of 2 sirolimus metabolites to sirolimus-free human whole blood or to I of the control samples supplied with the kit. In addition, whole-blood samples from patients receiving either cyclosporine or tacrolimus (N = 24) were analyzed for sirolimus. A comparison of the MEIA and a validated HPLC/MS/MS assay analyzed both pooled samples from patients receiving sirolimus and spiked samples (sirolimus 2-60 ng/mL). In a more extensive comparison of patient samples measured by the MEIA assay, a validated HPLC assay with UV detection (HPLC-UV) was used (HPLC-UV sirolimus 7-64 ng/mL).

RESULTS

Inaccuracy (between-run) was < or =16.2% at all 4 concentrations (N = 5). Within-assay imprecision (repeatability) was <6% (N = 5), and between-assay imprecision (reproducibility) for the same samples was < 11% (N = 5). Recovery, assessed by means of 3 in-house control samples prepared in both fresh and previously frozen sirolimus-free human whole blood, ranged from 93.9% to 109.5%. The limit of detection, determined by dilution of the lowest nonzero calibrator (3 ng/mL), was set at 1 ng/mL, at which repeatability was 20.5% (N = 5). Five ng/mL of hydroxysirolimus cross-reacted with the assay by a mean of between 44% and 50% (N = 4); 5 ng/mL of 41-O-demethylsirolimus cross-reacted with the assay by a mean of between 86% and 127% (N = 4). Assay specificity was further challenged by ethylenediamine-tetraacetic acid (EDTA)-whole-blood samples from transplant patients not receiving sirolimus. These samples had tacrolimus and cyclosporine concentrations of 7.8 to 15.9 ng/mL and 38 to 485 microg/L, respectively. The median result was 0 ng/mL (third quartile, 0.7 ng/mL; maximum, 1.4 ng/mL); no value was above the lowest nonzero calibrator. The results of the comparison between the MEIA and the HPLC/MS/MS assay showed mean positive biases of 21% and 8% for the MEIA in measuring sirolimus in pooled patient samples and spiked samples, respectively. The results of the comparison of the MEIA and HPLC-UV median sirolimus concentrations were 18.2 and 20.1. Whole-blood samples anticoagulated with EDTA and containing sirolimus were stable for analysis by MEIA for 3 freeze-thaw cycles when stored at -20 degrees C and for 10 days when stored at 4 degrees C or at ambient temperature. A decline in sirolimus concentration occurred when samples were stored at 37 degrees C.

CONCLUSION

The MEIA showed suitable precision across a clinically relevant concentration range. In terms of patient management, the practical significance of cross-reactivity with sirolimus metabolites remains to be assessed.

A new route to spirooxindoles

[reaction: see text]Reaction of indole amides 5 with tributylstannane gave spiroindolenines 9 which are readily converted into spiropyrrolidinyloxindoles. This tricyclic system is found in a number of interesting natural products.

Activity of antibiotics used in human medicine for Campylobacter jejuni isolated from farm animals and their environment in Lancashire, UK

A retrospective study of 96 Campylobacter jejuni isolated from farm animals and the environment showed that most were less susceptible than the NCTC type strain to nalidixic acid (MICs 4-32 mg/L), ciprofloxacin (MICs 1-2 mg/L) and erythromycin (MICs 16-64 mg/L), but had similar susceptibility to tetracycline (MICs 4-8 mg/L) and kanamycin (MICs 4-8 mg/L). None had the high MICs of ciprofloxacin (>32 mg/L) or erythromycin (1024 mg/L) typically associated with clinical resistance in this species. Some farms used antimicrobial agents, but there was no obvious association between the use of agents and the susceptibility of the isolates.

Effects of teacher feedback on the reputations and peer perceptions of children with behavior problems

We explored whether teacher feedback modified children's preferences and perceptions of a target child with behavior problems. First- and second-grade children (M age = 7.8 years) viewed a videotape of a target actor presented as having a liked, average, or disliked reputation. A second videotape depicted a teacher's verbal responses to the target's behavior as (a) positive, (b) neutral-salient, or (c) corrective. Both salience and valence of teacher feedback were assessed. Main effects of feedback and reputation indicated that feedback had at least minimal effects at each level of the target's reputation. Teacher feedback is discussed with respect to its effects on perceptions of behavior versus affective responses toward behavior-problem children. A significant interaction showed that when combined with a liked reputation, positive and neutral-salient feedback conditions increased the salience and positive evaluation of the target child, thus illustrating the importance of considering nonevaluative teacher attention in combination with children's reputational status.

Real-time transmission of full-motion echocardiography over a high-speed data network: impact of data rate and network quality of service

With high-resolution network transmission required for telemedicine, education, and guided-image acquisition, the impact of errors and transmission rates on image quality needs evaluation.

METHODS

We transmitted clinical echocardiograms from 2 National Aeronautics and Space Administration (NASA) research centers with the use of Motion Picture Expert Group-2 (MPEG-2) encoding and asynchronous transmission mode (ATM) network protocol over the NASA Research and Education Network. Data rates and network quality (cell losses [CLR], errors [CER], and delay variability [CVD]) were altered and image quality was judged.

RESULTS

At speeds of 3 to 5 megabits per second (Mbps), digital images were superior to those on videotape; at 2 Mbps, images were equivalent. Increasing CLR caused occasional, brief pauses. Extreme CER and CDV increases still yielded high-quality images.

CONCLUSIONS

Real-time echocardiographic acquisition, guidance, and transmission is feasible with the use of MPEG-2 and ATM with broadcast quality seen above 3 Mbps, even with severe network quality degradation. These techniques can be applied to telemedicine and used for planned echocardiography aboard the International Space Station.

Expression of nitric oxide synthase isoforms and arginase in normal human skin and chronic venous leg ulcers

Chronic venous ulcers, an example of abnormal wound healing, show chronic inflammation with defective matrix deposition which together with the underlying vascular pathology, result in delayed healing. L-arginine is known to be metabolized by one of two pathways: nitric oxide synthase (NOS), producing nitric oxide (NO), or arginase, producing ornithine. NO is involved in many pathological conditions including vascular and inflammatory disorders. This study therefore investigated the distribution, level and activity of NOS and arginase in chronic venous ulcers in comparison with normal skin, using immunocytochemistry, western blotting, and enzyme assays. The results demonstrated an increased distribution of both NOS and arginase in chronic venous ulcer tissue compared with normal skin, with inflammatory cells and vascular endothelial cells as the main sources. These data were confirmed by western blot analysis, which showed increased levels of both enzymes in chronic venous ulcers. Moreover, there was significantly increased activity of both total NOS (p<0.04) and inducible NOS (p<0.05) in chronic venous ulcer tissue compared with normal skin, and significantly increased activity of arginase (p<0.01) in chronic venous ulcer tissue in comparison with normal skin. NO is known to combine with hydroxyl free radicals forming peroxynitrite, a potent free radical which causes tissue destruction. NO overexpression in chronic venous ulcers may be involved directly or indirectly (through production of peroxynitrite) in the pathogenesis and delayed healing of chronic venous ulcers, through its effects on vasculature, inflammation, and collagen deposition. Arginase is known to enhance matrix deposition. Thus, increased levels of arginase in chronic venous ulcers could contribute to the pathogenesis of lipodermatosclerosis associated with chronic venous insufficiency, predisposing to the formation of chronic venous ulcers and also to matrix cuff formation around blood vessels.

Biomimetic ligands for transition metals: catechol-containing peptides

The tetrapeptide ligands 6a and 6b containing a catechol moiety have been synthesised and their metal binding with Fe(III), Mn(III) and Cu(II) has been studied using fluorescence spectroscopy.

Formation of a full complement of cranial proprioceptors requires multiple neurotrophins

Inactivation of neurotrophin-3 (NT3) completely blocks the development of limb proprioceptive neurons and their end organs, the muscle spindles. We examined whether cranial proprioceptive neurons of the trigeminal mesencephalic nucleus (TMN) require NT3, brain-derived neurotrophic factor (BDNF) or neurotrophin-4 (NT4) for their development. Complements of TMN neurons and masticatory muscle spindles were decreased by 62% in NT3 null mutants, 33% in BDNF null mutants, and 10% in NT4 null mutant mice at birth. The extent of proprioceptive deficiencies differed among different masticatory muscles, particularly in NT3 null mice. Masticatory muscles of embryonic mice heterozygous for the NT3(lacZneo) or BDNF(lacZ) reporter genes expressed both NT3 and BDNF, consistent with target-derived neurotrophin support of TMN neurons. Although more than 90% of TMN neurons expressed TrkB as well as TrkC receptor proteins by immunocytochemistry in wild-type newborns, TrkC or TrkB null mice exhibited only partial proprioceptive deficiencies similar to those present in NT3 or BDNF;NT4 null mice. Thus, in terms of the survival outcome, two main subpopulations of TMN neurons may exist during embryogenesis, one dependent on TrkC/NT3 functioning and the other utilizing TrkB/BDNF signaling. The differential dependence of TMN neurons on neurotrophins may reflect differential accessibility of the neurons to limiting amounts of NT3, BDNF, or NT4 in target tissues, especially if the tissue distribution or levels of BDNF, NT3, and NT4 were dynamically regulated both spatially and temporally.

Do psychosocial variables predict the physical growth of infants with orofacial clefts?

This study sought to determine whether psychosocial variables (parent-infant feeding interactions, infant temperament, maternal social support, family socioeconomic status) are important in predicting the physical growth of infants with orofacial clefts, after controlling for selected medical variables (infant health status, cleft diagnosis, and previous weight). Infant growth (weight-to-height zscores) was tracked for 2 years, and models were developed to predict growth at 3, 12, and 24 months. The authors also examined the growth trajectories of infants with different cleft types: cleft lip and palate (CLP) and cleft palate only (CPO). CPO infants showed some increase in their growth relative to the population mean over time, whereas the growth of CLP infants remained lower than the population mean at all time points. After controlling for medical variables, psychosocial variables collectively accounted for an additional 42% of the variance in infants' growth at 3 months of age, but they did not account for growth at 12 months and 24 months, largely due to the strong effect of previous growth. The authors tentatively conclude that psychosocial variables influence the early growth trajectory of infants with clefts, but subsequent growth becomes increasingly regulated by biological factors.

Mental health needs and services for severely troubled and troubling young people including young offenders in an N.H.S. region

Penal, social services, special education and health agencies in one National Health Service Region were screened for severely troubled and troublesome young people in need of mental health services. One hundred and sixteen detailed assessments were undertaken on young people: 57 in "penal" and 59 in "welfare" establishments. Little difference was found between those in these two types of setting except that the "penal group" were much more likely to have high levels of violent behaviour and to have had more changes of placement. The needs for mental health care greatly outstripped supply. As part of this overall neglect, 11 of 15 young people with serious mental illnesses and all 13 who had suffered sexual abuse in the sample were not receiving appropriate treatment. A tentative estimate of the size of the problem in the region yielded a rate of around 11.4 per million with very severe disorder but this is probably an under estimate. The effectiveness of treatment for the problems of these young people is discussed and a possible structure for a service is explored.

Prescribing patterns for asthma by general practitioners in six European countries

To assess the level of concordance with international consensus on asthma management, we compared primary care prescribing patterns for asthma in different European countries. A prospective study of prescription items with an associated diagnostic label of asthma in patient consultations with a total of 235 general practitioners (GPs) from Belgium, England, Ireland, Italy, Northern Ireland, Portugal, Scotland and Spain was performed. A total of 101,544 consecutive consultations were recorded in autumns 1994 and 1995 of which 3595 (3.5%) were for patients with asthma and 3243 (3.2%) were for patients receiving a prescription for asthma. Overall, asthma consultations varied from 1.8% in Italy to 5.8% in Ireland (mean 3.4%, SD 1.6). Prescribed inhaled medications for children varied from 72% of the total asthma prescriptions in Ireland and Portugal to 82% in Northern Ireland (mean 79%, SD 8.1) and for adults 55% in Italy to 85% in Spain (mean 70%, SD 10). Inhaled corticosteroid usage for adults varied from 14% in Italy to 31% in Northern Ireland (mean 24%, SD 6.4). For children, beta2-agonist use varied from 24% in Italy to 67% in Spain (mean 45%, SD 13). Despite publication of international guidelines for the management of asthma, inter-country prescribing practices vary considerably and could be improved. The frequency of use of asthma as a diagnostic label also varies markedly.

Are infants with orofacial clefts at risk for insecure mother-child attachments?

OBJECTIVE

Several risk factors in the early lives of children with clefts are believed to interfere with their development of secure attachments to parents; however, this possibility has rarely been studied empirically. This study compared 12- and 24-month attachment classifications of infants with cleft palate (CP), infants with cleft lip and palate (CLP), and a comparison group of unimpaired infants (COMP).

METHOD

Twenty-two CP infants, 24 CLP infants, and 61 matched COMP infants were assessed at 12 and 24 months of age in an urban children's hospital. At both visits, mothers and infants participated in the Strange Situation, which was videotaped and subsequently coded for patterns of attachment behavior.

RESULTS

CP infants displayed a lower rate of 12-month attachment security than infants in the CLP or COMP groups. By 24 months, no diagnostic group differences in attachment classification were found. Stable 12- to 24-month attachment classifications were less likely in the CP group (36.3%) than in the COMP (62.3%) group. CP infants who were insecure at 12 months were more likely to become secure by 24 months than were CLP or COMP group infants.

CONCLUSIONS

In contrast to previous theory and clinical speculation, the facial appearance of infants with CLP does not appear to affect the early mother-infant relationship adversely. The infancy period is marked by attachment instability for infants with CP, who demonstrated lower-than-expected rates of security at 12 months. However, these problems resolved in nearly all cases by 24 months of age. Most infants with clefts emerged from the first 2 years of life with secure maternal attachments.

Diaries of evidence-based tutors: beyond 'numbers needed to teach'

Interprofessional evidence-based health care courses have been held throughout the UK over the last few years, modelled on the approach used in McMaster University of using problem-based facilitated small-group formats to achieve the stated goals. Both delegates and tutors have been aware of the tensions which are inherent within these courses between: (a) the variation in learning cultures which is exhibited by the delegates and the effect this has on processes (i.e. the tension between the reductionist approach of bioscience and the more qualitative leanings of the applied and 'caring' disciplines); and (b) the conflict which arises between the goal of 'learning' applied healthcare biostatistics and the ability to leave the course with the skills to teach others. This qualitative study uses tutor-kept diaries to understand some of the tensions apparent to the teaching faculty during a week-long course in Wales, UK.

Predicting small-area health-related behaviour: a comparison of smoking and drinking indicators

Health-related behaviours are of central importance to health promotion and to the promotion of enhanced population health. In the UK, localised knowledge of the quantitative dimensions of health-related behaviours is traditionally attained by conducting a costly sample survey. Such surveys seldom generate reliable data at scales more local than that of the health authority, they also need to be repeated regularly. This paper outlines an alternative framework for generating statistics on small-area health related behaviours using routinely available data from the annual Health Survey for England (N = 17,000) and the decennial Population Census. Using a multilevel modelling approach nesting individuals within postcode sectors within health authorities, and focusing on the prevalence of smoking and 'problem' drinking, the paper comprises four sections: a consideration of the modelling strategy, a comparison of the smoking and drinking models, an outline of the estimation strategy, and the presentation and discussion of ward-level estimates of smoking and drinking behaviour for England. The paper concludes that the method is better at estimating smoking than drinking but that it offers a feasible, cheap and more informative alternative to the survey approach to the generation of information on smoking and drinking behaviour.

The mechanism of adverse events associated with terazosin: an analysis of the Veterans Affairs cooperative study

PURPOSE

We determined the mechanism of adverse events associated with alpha1-blockers for treating benign prostatic hyperplasia (BPH).

MATERIALS AND METHODS

We randomized 1,229 men with clinical BPH at 31 Veterans Affairs medical centers into equal treatment groups, including those who received placebo, terazosin, finasteride, and combined terazosin and finasteride therapy, respectively. Adverse events were captured at all study visits during our 1-year study. Our current review of adverse events is limited to patients randomized to the placebo and terazosin groups. We compared the incidence of orthostatic blood pressure change, postural symptoms and orthostatic hypotension in men who were normotensive and hypertensive at baseline, respectively. We also determined the association of changes in systolic blood pressure with the incidence of treatment related adverse events.

RESULTS

The treatment related rates of dizziness, asthenia, postural hypotension and syncope were 19%, 6%, 6% and 1%, respectively. Of these adverse events only postural hypotension was associated with orthostatic blood pressure changes. The incidence of asthenia, dizziness and postural hypotension was not significantly greater in patients with a systolic blood pressure decrease of 5 or greater and less than 5 mm. Hg, respectively.

CONCLUSIONS

Dizziness and asthenia are not associated with changes in blood pressure, suggesting that these treatment related adverse events associated with alpha1-blockers are not related to vascular events. Designing a subtype selective alpha1 antagonist that has less effect on blood pressure may not result in marked improvement in tolerability over commercially available alpha1-blockers.

Use of structural magnetic resonance imaging to predict who will get Alzheimer's disease

We used magnetic resonance imaging (MRI) measurements to determine whether persons in the prodromal phase of Alzheimer's disease (AD) could be accurately identified before they developed clinically diagnosed dementia. Normal subjects (n = 24) and those with mild memory difficulty (n = 79) received an MRI scan at baseline and were then followed annually for 3 years to determine which individuals subsequently met clinical criteria for AD. Patients with mild AD at baseline were also evaluated (n = 16). Nineteen of the 79 subjects with mild memory difficulty "converted" to a diagnosis of probable AD after 3 years of follow-up. Baseline MRI measures of the entorhinal cortex, the banks of the superior temporal sulcus, and the anterior cingulate were most useful in discriminating the status of the subjects on follow-up examination. The accuracy of discrimination was related to the clinical similarity between groups. One hundred percent (100%) of normal subjects and patients with mild AD could be discriminated from one another based on these MRI measures. When the normals were compared with the individuals with memory impairments who ultimately developed AD (the converters), the accuracy of discrimination was 93%, based on the MRI measures at baseline (sensitivity = 0.95; specificity = 0.90). The discrimination of the normal subjects and the individuals with mild memory problems who did not progress to the point where they met clinical criteria for probable AD over the 3 years of follow-up (the "questionables") was 85% and the discrimination of the questionables and converters was 75%. The apolipoprotein E genotype did not improve the accuracy of discrimination. The specific regions selected for each of these discriminations provides information concerning the hierarchical fashion in which the pathology of AD may affect the brain during its prodromal phase.

Death and deprivation: an exploratory analysis of deaths in the health and lifestyle survey

An analysis is undertaken of deaths of respondents in the UK- representative Health and Lifestyle Survey. The sample was originally interviewed in 1984/5 and followed initially until May 1997. Using multilevel logistic and Cox-proportional hazards models, the relationships between death and a wide range of social circumstances and behaviours is explored. It is found that place deprivation interacts with individual social class in accounting for variations in mortality. This is the case even when account is taken of personal health-related behaviour. There appears to be some evidence of a threshold relationship such that the differential effects of social class are only found at high-levels of deprivation. No statistically significant interactions are found for social and behavioural variables, for behavioural and place deprivation variables, and for social and place deprivation variables with the exception of social class. The study is deliberately exploratory and a wide range of models have been fitted which will be subject to more rigorous evaluation as the HALS death study proceeds.

Comparison of selected perceptual variables for backpacks with internal and external frames

Differences in perceptions of comfort, exertion, balance, and heart rate were investigated with two types of backpack. Subjects were 20 male volunteers (M age = 24.3 yr., SD: 3.6, M height = 180.02 cm, SD: 8.0, and M weight = 86.46 kg, SD: 14.84). Following oral briefing and practice trials, each subject was fitted at random with either an internal- or external-frame backpack containing 18.2 kg. By random, cross-over design, subjects completed a 30-m simulated hiking trial consisting of 16 separate obstacles designed to resemble actual off-trail hiking. Trials were conducted in a controlled environment with the walking intensity regulated by a metronome. Upon completion of each trial, the subjects rated the experience on perceived comfort, balance and stability, and rating of perceived exertion. Heart rate was recorded immediately prior to and following each trial. Analysis yielded a significant difference only on rating of perceived exertion in favor of the internal-frame backpack. Under limited circumstances, these data suggest that both types of backpacks provide similar comfort and balance and stability; however, internal frames in backpacks may reduce perceived exertion during short, demanding hikes.

Cognitive and psychomotor development of infants with orofacial clefts

OBJECTIVE

To compare at ages 3, 12, and 24 months the cognitive and psychomotor development of 29 infants with cleft lip and palate (CLP), 28 infants with cleft palate only (CPO), and a demographically matched comparison (COMP) group of 69 infants; to examine predictors of cognitive status at age 24 months in the cleft group.

METHODS

Infants were administered the Bayley Scales of Infant Development (BSID), mother-infant interactions were observed, and medical records were reviewed.

RESULTS

CLP and CPO groups scored lower than the COMP group on the BSID, but did not differ from one another. Cleft group infants scored lower than COMP group infants on BSID items assessing nonverbal and expressive language skills. Quality of maternal interaction predicted the 2-year Mental Development Index (MDI) scores of infants with clefts.

CONCLUSIONS

Infants with clefts show relative deficits in cognitive and psychomotor development. Cognitive deficits are apparent in nonverbal as well as verbal areas of performance.