MRI artefact in the rectum caused by ingested orthodontic brackets.

Magnetic susceptibility artefacts, caused by metallic objects, present a challenge in magnetic resonance imaging (MRI). In this case, MRI showed metal-induced artefact in the rectum of a 14-year-old girl who presented with pain in the coccyx after a snowboarding accident. Previous radiographs showed no evidence of metal in the area. After the identification of the artefact and upon discussion with the patient, she disclosed that two orthodontic brackets had been swallowed two days prior to the MRI examination, likely the source of artefact. Following the passage of the brackets, subsequent MRI was artefact-free. A similar artefact was recreated by scanning a potato with and without an orthodontic bracket, highlighting the impact of the resulting artefact on MRI.

Placing ecosystem services at the heart of urban water systems management.

Current approaches have failed to deliver a truly integrated management of the different elements of the urban water system, such as freshwater ecosystems, drinking water treatment plants, distribution networks, sewer systems and wastewater treatment plants. Because the different parts of urban water have not been well integrated, poor decisions have been made for society in general, leading to the misuse of water resources, the degradation of freshwater ecosystems and increased overall treatment costs. Some attempts to solve environmental issues have adopted the ecosystem services concept in a more integrated approach, however this has rarely strayed far away from pure policy, and has made little impact in on-the-ground operational matters. Here, we present an improved decision-making framework to integrate the management of urban water systems. This framework uses the ecosystem service concept in a practical way to make a better use of both financial and water resources, while continuing to preserve the environment.

Comparing the performance of multiple mitochondrial genes in the analysis of Australian freshwater fishes.

In this study, four mitochondrial genes (cytochrome oxidase I, ATPase, cytochrome b and control region) were amplified from most of the fish species found in the fresh waters of south-eastern Queensland, Australia. The performance of these different gene regions was compared in terms of their ability to cluster fish families together in a neighbour-joining tree, both individually by gene and in all combinations. The relative divergence rates of each of these genes were also calculated. The three coding genes (cytochrome oxidase I, ATPase and cytochrome b) recovered similar number of families and had broadly similar divergence rates. ATPase diverged a little more quickly than cytochrome oxidase I and cytochrome b slightly more slowly than cytochrome oxidase I. All two-gene combinations recovered the same number of families. Results from the control region were much more variable, and, although generally possessing more diversity than the other regions, were sometimes less variable.

Phylogeographic structure in an Australian freshwater shrimp largely pre-dates the geological origins of its landscape.

The phylogeographic structure of cryptic lineages within the freshwater shrimp Caridina indistincta Calman, 1926 (Decapoda: Atyidae) was investigated in an attempt to unravel any potential genetic influences of Quaternary sea-level oscillations. The study was based on mitochondrial DNA sequences from specimens from lakes and creeks in the sand dune areas of southeast Queensland, eastern Australia. Four divergent lineages were identified, two of which were from Moreton and North (N.) Stradbroke Islands. Lineage 'C1' has been found only on Moreton Island and the western part of N. Stradbroke Island, whereas 'C2' was found on the eastern side of N. Stradbroke Island and a few locations on the mainland. These diverged from each other during the Late Miocene/Pliocene and so are older than the current landscape in which they are found. Small-scale phylogeographic analysis of C1 identified four separate geographic areas, within the two islands, whose divergences date to the Pleistocene (approximately 100-300 thousand years ago ('kya')). The N. Stradbroke Island population of C2 also diverged from the mainland during the Pleistocene, as did a sympatric freshwater fish Rhadinocentrus ornatus Regan, 1914 (Melanotaeniidae). This implies that the ice-age sea-level changes may have structured these populations, although there is little observable influence of the last glacial maximum (approximately 18 kya). Most estimates for the age of the landscape (dunes, lakes) also fall within the Pleistocene and so the effect of sea-level change may be seen both in biology and geology.

Biogeographic history of an Australian freshwater shrimp, Paratya australiensis (Atyidae): the role life history transition in phylogeographic diversification.

The widespread distribution of the freshwater shrimp Paratya australiensis in eastern Australia suggests that populations of this species have been connected in the past. Amphidromy is ancestral in these shrimps, although many extant populations are known to be restricted to freshwater habitats. In this study, we used a fragment of the cytochrome c oxidase I mitochondrial DNA (mtDNA) gene to examine diversity within P. australiensis and to assess the relative importance of amphidromy in its evolutionary history. We hypothesized that if transitions from an amphidromous to a freshwater life history were important, then we would find a number of divergent lineages restricted to single or groups of nearby drainages. Alternatively, if amphidromy was maintained within the species historically, we expected to find lineages distributed over many drainages. We assumed that the only way for divergence to occur within amphidromous lineages was if dispersal was limited to between nearby estuaries, which, during arid periods in the earth's history, became isolated from one another. We found nine highly divergent mtDNA lineages, estimated to have diverged from one another in the late Miocene/early Pliocene, when the climate was more arid than at present. Despite this, the geographic distribution of lineages and haplotypes within lineages did not support the notion of a stepping-stone model of dispersal between estuaries. We conclude that the extensive divergence has most likely arisen through a number of independent amphidromy-freshwater life history transitions, rather than via historical isolation of amphidromy populations. We also found evidence for extensive movement between coastal and inland drainages, supporting the notion that secondary contact between lineages may have occurred as a result of drainage rearrangements. Finally, our data indicate that P. australiensis is likely a complex of cryptic species, some of which are widely distributed, and others geographically restricted.

The cytotoxic effects of single-stranded telomere mimics on OMA-BL1 cells.

Telomerase is a ribonucleoprotein that adds 5'-d(TTAGGG)-3' hexameric repeats onto the 3' ends of chromosomes. High telomerase activity has been associated with immortal cells, transformed cells, mitogenic stimulation, and proliferative diseases. It is not clear what phenotype would be observed by transient inhibition of telomerase. Studies were designed to inhibit telomerase activity using a series of S-ODN telomere sequence motifs. The studies evaluated the length, hydrogen bonding, and sequence requirements of telomerase inhibition using the TRAP assay and a bioassay measuring cell viability following exposure to the compounds. In addition, we have also studied the role of the 3' end and secondary structure of telomere mimics on telomerase inhibition. Observations reveal that sensitivity to the S-ODNs may not require hybridization to an antisense target but required guanine nucleotides on the 3' end for cells in culture and telomerase inhibition in vitro. The importance of H bonding and the requirement for a free 3' end for the activity of these compounds has also been demonstrated. However, transient inhibition of telomerase is not cytotoxic to all immortal cells and is not sufficient to explain the mechanism of cytotoxicity of these short oligonucleotides.

Improving staff nutritional practices in community-based group homes: evaluation, training, and management.

We evaluated the effectiveness of a staff training and management package on nutritional practices in two community-based group homes serving adults with developmental disabilities. Food storage, menu development, and meal preparation were trained in a multiple baseline format, followed by supervisor feedback. All staff behaviors increased after training and were maintained for up to 1 year. Biological indices reflected collateral improvements in the health of consumers, and surveys of staff and parents established social validity.

Temporal distributions of problem behavior based on scatter plot analysis.

The scatter plot is a commonly used assessment tool for identifying temporal patterns in the occurrence of behavior problems. However, the extent to which such patterns are frequently observed is unknown because little research has evaluated the general utility of the scatter plot. We conducted a large-scale analysis of within- and across-day occurrences of problem behavior by conducting continuous observations of 20 individuals living in four residential facilities. Data were recorded during 30-min intervals throughout participants' waking hours for 30 days by direct care staff and were converted into scatter plot formats. Five sets of data were excluded from further analysis due to poor interobserver agreement (below 80%). Visual analysis of the remaining 15 scatter plots indicated that none showed any reliable temporal pattern of responding. However, when the data were transformed into aggregate "control charts" based on statistical process control procedures, 12 of the 15 sets of data revealed one or more 30-min intervals during which problem behavior was more likely to occur. Results are discussed in terms of the practicality of applying statistical analyses to scatter plot data and of collecting data for the length of time needed to show statistical significance. It was concluded that detailed functional or descriptive analyses, which would reveal cause-effect or correlational relationships between behavior and specific environmental events, may be both more precise and more efficient forms of assessment.

A hexameric phosphorothioate oligonucleotide telomerase inhibitor arrests growth of Burkitt's lymphoma cells in vitro and in vivo.

A phosphorothioate oligonucleotide (PS-ODN) with sequence identical to the repeat sequence of the mammalian telomere, 5'-d(TTAGGG)-3', was incubated with a Burkitt's lymphoma-derived (OMA-BL1) cell line. This hexanucleotide inhibits telomerase activity in cell lysates, lengthens cell doubling time, and induces apoptosis. Concatenated repeats (12-, 18-, and 24-mers) of the 5'-d(TTAGGG)-3' motif induce similar cellular responses. Scrambled sequences do not efficiently inhibit telomerase activity or significantly alter cell growth and viability. The in vivo efficacy of this PS-ODN was evaluated in a xenograft human-nude mouse model. Once tumors were established these animals were administered the telomere mimic, 5'-d(TTAGGG)-3', a control scrambled sequence 5'-d(TGTGAG)-3', or saline for 14 days via a subcutaneous osmotic pumps in a blinded study monitoring tumor size with dose and time. A significant decrease in tumor size was observed in animals given 50 micrograms/mouse/day 5'-d(TTAGGG)-3', but not following 5'-d(TGTGAG)-3', relative to the saline-treated animals. The antitumor activity of the 6-mer telomere mimic demonstrated a dose dependency including a reduction in metastatic nodules in the spleen. No activity was observed with the scrambled controls. In addition to antitumor activity we observed an increase in the mouse hematopoietic progenitor cell populations, BFU-e and CFU-GM. These results demonstrated the effects of a short hexameric oligonucleotide telomere mimic in vitro and in vivo and the potential utility of short oligonucleotides as telomerase inhibitors.

Teaching refusal skills to sexually active adolescents.

Refusal skills training was extended to sexually active handicapped female adolescents who lacked an effective refusal strategy. Role-plays for assessment and training were developed using the who, what, when and where of situations which resulted in unwanted intercourse. Refusal skills were trained following the format of rationale, modeling, rehearsal, feedback, and reinforcement. Baseline rates of most target behaviors were quite low. High frequencies of target behaviors were observed as each behavior became the focus of training. Generalization across staff and time was also observed. The skillfulness and effectiveness of the subjects' refusal skills were judged to be improved as a function of training. One-year follow-up showed decreased sexual activity for each girl.

PIP: In an attempt to curtail adolescent pregnancy, refusal skills were taught to 2 sexually active and handicapped female adolescents. The goal was to surpass the just say no philosophy by 1) socially validating each girl's effectiveness and skill, and 2) extending refusal skills training to special populations, where skill deficits may be more prevalent and the need the greatest. One child Amy, 16 years) was dead and was being treated for sexual disorders, and the other (Karen, 14 years) was developmentally delayed and sexually precocious. Both desired refusal skills. Training was designed to teach skills to effectively refuse sexual advances when they deemed it necessary and desirable to do so. An assessment was made for each girl. A role play vignette was developed for each girl which relied on her past experiences. The performance of the role play was videotaped in order to identify the particular deficits in refusal assertion. Refusal, specification, leaving the situation, and eye contact were situations that were categorized as either an occurrence or nonoccurrence for the pre- and postassessments. Skills were taught based on rationale, feedback, modeling, behavioral rehearsal, and reinforcement. 8 randomly ordered play roles were analyzed by 2 observers to evaluate social perception of client refusal skills and effectiveness. Reliability was evaluated using Cohen's Kappa (K). The K for eye contact was .84; refusal , .85; leaving the situation, 1.0; and specifying objectionable behavior, .90. The deaf child, Amy, initially showed only eye contact skills, while Karen used only verbal refusal before skills training. The intervention created long and shortterm effects, i.e., use of target behaviors posttraining, at a 2-week follow up with nonintervention staff, and a 1-year telephone follow up which indicated decreased sexual activity for each girl. Significant differences were found in the baseline and posttreatment performance ratings for both refusal and effectiveness (F=103.02, df=27.3, p=.001; and F=243.7, df=27.3, p.001). For Karen only refusal skill rating was significantly changed (F=22.06, df=27.3, p=.001). There is a need to provide additional research to verify the actual effectiveness of refusal skills packages and their impact on the occurrences of unwanted sexual behavior. Refusal components, developmental factors, societal norms, familial and peer pressure that are most critical need to be determined. Generalizability is limited.

Assessing independent and interactive effects of behavioral and pharmacologic interventions for a client with dual diagnoses.

Behavior analytic methods were applied to the assessment and treatment of the problem behaviors of an 8-year-old male classified as having moderate mental retardation and atypical psychosis. Functional assessment procedures demonstrated that verbal behaviors diagnosed as hallucinatory were affected by environmental contingencies. Next, a multi-element/multiple baseline design was used to evaluate the independent and interactive effects of contingency management and pharmacologic interventions on three dependent variables: (1) psychotic speech; (2) aggressive-disruptive behavior; and (3) appropriate speech. Results indicated that contingency management without haloperidol was the most effective treatment for all inappropriate and appropriate behaviors. These results are important in that behavior analytic methods were shown to have utility for: (1) assessing the functional relationship between environmental contingencies and behaviors related to differential diagnosis; and (2) evaluating the independent and interactive effects of behavioral and pharmacologic treatments.

Teaching self-catheterization skills to children with neurogenic bladder complications.

We examined the effects of simulation training on the acquisition of self-catheterization skills in 2 female children with spina bifida. Based on a task analysis, the children were taught to perform on a doll each of the components of preparation, and, using a mirror to locate the urinary meatus, to insert and remove the catheter and to clean-up. Before, during, and after training, the children's performance of the skills on the doll and on themselves was assessed. Results of a multiple baseline design across subjects and skill components showed that doll training facilitated the children's acquisition of self-catheterization skills.

Enhancing child compliance with nebulized respiratory treatment. A case study.

A 2.7-year-old developmentally delayed boy diagnosed as having chronic lung disease, severe hyaline membrane disease, and persistent pulmonary hypertension with interstitial emphysema was referred in hopes of modifying his refusal to wear a mask during nebulized administrations of Chromolyn. The child was prescribed four 20-minute nebulized treatments daily but resisted treatment and removed the mask by turning his head and pushing the mask away with his hands. A procedure was implemented to gradually teach the child that turning his head and pushing the mask would not result in mask removal, and that by wearing the mask he would receive positive attention. By the end of treatment, the child was consistently wearing his mask for the required 20-minute intervals. Follow-up at 3 months confirmed maintenance of treatment effects.

Assessment and treatment of multiple behavior problems exhibited by a profoundly retarded adolescent.

The severe aggression and noncompliance of a profoundly retarded blind male were subjected to extensive behavioral assessment in order to identify controlling variables. The assessment, conducted across settings and therapists, suggested that these inappropriate behaviors functioned to avoid or terminate nonpreferred activities. Intervention consisted of manual guidance when there was noncompliance with instructions and edible reinforcement upon compliance; there were no direct contingencies for the inappropriate behaviors. Treatment procedures were implemented in a multiple baseline design across therapists and settings. Results show that the intervention consistently increased compliance, with concurrent decreases in inappropriate behaviors. Edible reinforcement and neuroleptic medication were withdrawn systematically with no loss of therapeutic gains. Family members and school personnel were trained to use the intervention procedures. Results are discussed in terms of functional assessment, response covariation, compliance training, parent and staff training, and behavioral assessment of the effects of neuroleptic medication.

Analysis of environmental determinants of aggression and disruption in mentally retarded children.

This study evaluated methods for empirically identifying environmental determinants of aggressive and disruptive behavior in three developmentally delayed children. A variety of sessions conducted on an inpatient treatment unit were designed to stimulate contingencies maintaining aggression and disruption in the subjects' natural environments. The basic analog conditions included: instructional demands, contingent social disapproval, and structured play. In addition, variations of the three basic conditions were developed based on informal observation and parental reports of naturally occurring contingencies. Results showed considerable variability both between and within subjects. However, for each subject a specific analog condition was shown to produce relatively higher rates of aberrant behavior. Subsequently, behavioral treatments based on assessment results were successfully implemented with two of the subjects. Results are discussed in terms of the importance and practical limitations of conducting systematic assessment of aberrant repertoires in developmentally delayed clients.

Effectiveness of brief time-out with and without contingent delay: a comparative analysis.

We evaluated a commonly used component of brief time-out, in which release from time-out is delayed contingent on the occurrence of disruption. Data were collected for one normal and two mentally retarded children on time-out-producing behaviors (aggression and disruption) as well as delay-producing behaviors during time-out (loud vocalizations, out-of-chair, aggression, and disruption). The results of a combination ABAC reversal and multiple-baseline design indicated that, under the conditions used in this investigation, both delay and no delay variations were effective in reducing the frequency of the target behaviors. Implications for the use of time-out to reduce aberrant behaviors are discussed.

Simulation procedures for teaching independent menstrual care to mentally retarded persons.

Four mentally retarded adolescent females participated in a program for assessment and training of independent menstrual care skills. Three task analyses served as the basis for instruction: (a) menstrual stain on underwear, (b) menstrual stain on a sanitary pad, and (c) menstrual stain on both sanitary pad and underwear. During individual training sessions, subjects were taught to perform correct sequences via simulation training with a small doll, in which a trainer utilized instructions, praise, modeling, and corrective feedback. Three types of assessment probes were conducted prior to training, upon completion of specified mastery criteria, and during post-training follow-up sessions. Doll probes assessed performance with the toy doll, self-probes assessed naturalistic performance but under conditions of simulated menstruation, and in vivo probes assessed performance during actual menstruation. Results of a multiple baseline analysis indicated that subjects emitted few correct responses during baseline probes, but showed consistent improvements that corresponded to the introduction of training. Generalization to untrained skills was noted with all subjects. Follow-up assessments indicated maintenance of skills for periods up to 30 weeks following termination of training.

Clinical behavioral pharmacology: methods for evaluating medications and contingency management.

We evaluated methods for comparing the effects of dextroamphetamine (Dexedrine), thioridazine (Mellaril), and contingency management in the control of severe behavior problems. A reversal design was used in which medications were systematically titrated and assessed in unstructured as well as structured settings with three clients. Subsequently, behavioral procedures including timeout, differential reinforcement of other behavior, and visual screening, were used in a multiple-baseline design across settings. The assessment and design methods were useful in comparing the interventions. Dextroamphetamine decreased inappropriate behaviors and improved academic behaviors in one client, but no reliable effects were observed in the other two clients. Thioridazine was variable across clients, settings, behaviors, and dosages. Contingency management produced consistent decreases in inappropriate behaviors and small improvements in academic performance.

Assessment of stimulus preference and reinforcer value with profoundly retarded individuals.

We evaluated a procedure for identifying potential reinforcers with profoundly retarded individuals. In Experiment 1, six persons were repeatedly exposed to 16 stimuli, and approach behaviors to each stimulus were used to identify preferred and nonpreferred stimuli. In Experiment 2, we examined the reinforcing properties of preferred and nonpreferred stimuli by delivering them contingently on the occurrence of arbitrarily selected responses. Results revealed that the preferred stimulus conditions typically produced higher rates of responding than did either the baseline or the nonpreferred stimulus conditions, suggesting that the procedure can be used to assess reinforcer value for individuals with limited behavioral repertoires.