Haloacetate-induced oxidative damage to DNA in the liver of male B6C3F1 mice.

Brominated and chlorinated haloacetates (HAs) are by-products of drinking water disinfection. Dichloroacetate (DCA) and trichloroacetate (TCA) are hepatocarcinogenic in rodents, but the brominated analogs have received little study. Prior work has indicated that acute doses of the brominated derivatives are more potent inducers of oxidative stress and increase the 8-hydroxydeoxyguanosine (8-OH-dG) content of the nuclear DNA in the liver. Since, DCA and TCA are also known as weak peroxisome proliferators, the present study was intended to determine whether this activity might be exacerbated by peroxisomal proliferation. Classical responses to peroxisome proliferators, cyanide-insensitive acyl-CoA oxidase activity and increased 12-hydroxylation of lauric acid, were elevated in a dose-related manner in mice maintained on TCA and clofibric acid (positive control), but not with DCA, dibromoacetate (DBA) or bromochloroacetate (BCA). Administration of the HAs in drinking water to male B6C3F1 mice for periods from 3 to 10 weeks resulted in dose-related increases in 8-OH-dG in nuclear DNA of the liver with DBA and BCA, but not with TCA or DCA. These findings indicate that oxidative damage induced by the haloacetates is, at least in part, independent of peroxisome proliferation. In addition, these data suggest that oxidative damage to DNA may play a more important role in the chronic toxicology of brominated compared to the chlorinated haloacetates.

Lipid peroxidation and formation of 8-hydroxydeoxyguanosine from acute doses of halogenated acetic acids.

Chlorinated, brominated, and mixed bromochloro acetates are major by-products of water disinfection by chlorine or ozone. The chlorinated acetates, trichloroacetate (TCA) and dichioroacetate (DCA), are carcinogenic in rodents. Brominated analogs of TCA and DCA have received little study. TCA and DCA induce lipid peroxidation in the livers of rodents when administered acutely. Oxidative stress can also result in oxidative damage to DNA, most commonly measured as increases in 8-hydroxydeoxyguanosine (8-OHdG) adducts. In this study, the ability of acute doses of TCA, DCA, dibromoacetate (DBA), bromodichloroacetate (BDCA), and bromochloroacetate (BCA) to induce lipid peroxidation and 8-OHdG formation was examined. Male B6C3F1 mice developed significant increases in 8-OHdG/dG ratios in nuclear DNA isolated from livers when treated with haloacetates. The extent of 8-OHdG formation appeared to be related to the ability to induce thiobarbituric acid-reactive substances (TBARS). The order of potency was DBA = BCA > BDCA > DCA > TCA. The induction of 8-OHdG was found to be generally more sensitive to treatment with haloacetates than the TBARS response. Significantly elevated levels of 8-OHdG were observed at doses of DBA, BCA, and BDCA as low as 30 mg/kg. We suggest that formation of 8-OHdG by brominated haloacetates may contribute to their toxicological effects.

Part 2: using a competency-based curriculum to train experienced nurses in ventilator care.

As pediatric nurses, we are caring for increasing numbers of children with special health needs such as tracheostomy and ventilator care. These children are being discharged to their families requiring specialized care, including in-home skilled nursing services. In Part I of this two-part series, the authors described the development of a training curriculum for nurses caring for ventilator-assisted children at home. The next step was to validate that the curriculum was effective, feasible, and replicable. Part 2 describes the initial validation efforts with hospital and home care nurses.

Developing a competency-based curriculum for tracheostomy and ventilator care.

Advances in technology and medical practice have enabled children with special health needs, such as tracheostomy and ventilator care, to be discharged to their families while continuing to require specialized care. Yet, corresponding increases in the availability and competence of home care providers have not kept pace with this trend. The authors set a goal to design, develop, implement, validate, and disseminate a competency-based curriculum to prepare adults to care for these children in the home and community. This article is Part 1 of a two-part series.

Training parents to observe and record: a data-based outcome evaluation of a pilot curriculum.

Despite the prevalence of training parents in the use of child behavior management strategies, relatively little investigative attention has been devoted to promoting acquisition of parent observational and recording skills. In this study, we examined the efficacy of a brief curriculum designed to teach parents how to observe and record targeted child behaviors systematically. Subsequent to instruction, each of six participating parents demonstrated, in an analogue context, higher levels of both occurrence and nonoccurrence agreement, based upon their recordings of child behavior, when compared with those of a panel of experienced professionals. Agreement of parental recordings with those of professionals typically increased to a predetermined mastery criterion and stabilized subsequent to training, relative to a high degree of variability during baseline. Results are discussed in terms of directions for further refinement of the curriculum and additional study of its impact.

Spatial distribution of odors in simulated benthic boundary layer flows.

Many animals orient to odor sources in aquatic habitats where different flows and substrates affect the hydrodynamics of benthic boundary layers. Since the dispersal of chemicals is due to the fluid mechanics of a particular environment, we quantified the changes in the fine structure of an odor plume under different hydrodynamic conditions in the benthic boundary layer of a laboratory flume. We sampled turbulent odor plumes at 10 Hz using a microchemical sensor (150 µm diameter) under two flow speeds: 3.8 and 14.4 cm/sec, and at 1, 8, 50 mm above the substrate. These distances above the substrate occur within different flow regions of the boundary layer and correlate with the location of crustacean chemosensory appendages within boundary layer flows. The high flow velocity exhibited a greater level of turbulence and had more discrete odor pulses than the low flow velocity. In general, odor signals showed a high level of temporal variation in fast flow at heights 1 and 8 mm above the substrate. In slow flow, temporal variation was maximal at 50 mm above the substrate, exhibiting more variance than the same height at the fast flow. These patterns of odor signals resulted in part from differences in the height above the substrate of the main axis of the odor plume at the two flow speeds. Our results imply that animals chemically orienting to an odor source will need to compensate for varying hydrodynamic properties of odor transport and dispersal. The method by which animals extract spatial information from odor plumes will need to account for changing flow conditions, or else it will not be equally efficient in extracting information about chemical spatial distributions.

Behavior management in the child with developmental disabilities.

Pediatricians who serve children with developmental disabilities would be well advised to study and practice applied behavior analysis. Within a behavior analytic framework, the pediatrician views the child's aberrant performance as being a constellation of behavioral excesses and skill deficits that serve a functional purpose, rather than as being a symptom of some underlying illness or intrapsychic mechanism. The pediatrician can counsel the child, parents, and teachers to rearrange their environment, with an emphasis on how they can behave differently toward one another in specific situations, so as to alter the target behavior. When the child's problem behaviors are relatively severe or intractable, the pediatrician can refer the patient and family to a behavior specialist while continuing to support efforts to improve the child's overall health and adjustment.

Using guided compliance versus time out to promote child compliance: a preliminary comparative analysis in an analogue context.

Children referred to child management clinics frequently exhibit noncompliance with adult requests. Using a counterbalanced ABAC design, the authors examined the relative efficacy of guided compliance versus time out as a method of promoting child adherence to adult requests. Time out effected larger increases in percentage compliance among four of five participating children.

Measurement of Microscale Patchiness in a Turbulent Aquatic Odor Plume Using a Semiconductor-Based Microprobe.

The distribution of chemical signals within aquatic environments is highly patchy and heterogeneous due to dispersion by turbulent eddies. We aimed to quantify the smallest spatial scales associated with chemical patches, and therefore measured the structure of chemical signals under turbulent flow simultaneously at two chemical sensors spaced from 200 to 800 {mu}m apart. Measurements were done under controlled stimulus and flow conditions with a novel semiconductor-based, multisite, microelectrochemical electrode (5-2000 {mu}m2 surface area sensors) and a high-speed computer-based recording system. The chemical signals received at the sensor were intermittent, with wide fluctuations in concentration. Patchiness in signal structure was found at spatial scales as small as 200 {mu}m. Significant differences in signal height were found between recordings made at probes spaced 200, 400, 600, and 800 {mu}m apart. These data demonstrate that sub-millimeter patches occur in aquatic turbulent odor plumes. Such differences in chemical signal structure over small spatial scales might be important for marine animals that employ olfactory orientation. We propose alternative ways by which organisms might deal with these fine scale differences in odor concentration. Animals much larger than microscale patches may have evolved elongated olfactory organs that integrate signals, thereby smoothing variations in sensory input. Animals about the same size as micropatches may be able to capitalize on microscale variation by extracting directional information from turbulent odor plumes.

Teaching developmentally disabled children with chronic illness to swallow prescribed capsules.

Child noncompliance with prescribed medical regimens, including nonacceptance of oral medication, frequently impedes medical treatment and achievement of clinical aims. During this study, we used a single-subject experimental design to evaluate the effectiveness of a capsule-swallowing training curriculum specifically developed to promote acceptance of oral medication by multihandicapped children. Four such children participated, each diagnosed with a chronic pediatric illness requiring daily intake of oral medication. Training consisted of verbal instruction, demonstration, reinforcement for swallowing candies/capsules progressively larger in size, ignoring mild inappropriate behavior, and gradually providing less guidance and structure. In each case, the curriculum produced routine independent swallowing of prescribed capsules/tablets. Follow-up assessments, coupled with parent satisfaction ratings, suggest that skill acquisition was both enduring and clinically significant. This study validates a brief, readily exportable, and effective approach to teaching handicapped children to swallow capsules.

Phone phobia, phact or phantasy? An operant approach to a child's disruptive behavior induced by telephone usage.

The clinical efficacy of a contingency management program for treating a developmentally disabled girl referred for telephone phobia was evaluated using both a multiple baseline across settings design and a reversal design. A descriptive analysis indicated that the 'phobia' was in all probability an operant, rather than a respondent. The treatment, consisting of differential reinforcement, extinction and time-out, was effective in reducing the frequency and intensity of disruptive behaviors in response to telephone usage. Follow-up assessments at 1, 3, and 6 months revealed that treatment gains were maintained.

Teaching self-administration of suctioning to children with tracheostomies.

We examined the effectiveness of using dolls to teach young children with tracheostomies to self-administer a suctioning procedure. Four children between the ages of 5 and 8 years, who had had tracheostomies for 6 months or longer, participated. After skills were taught via doll-centered simulations, in vivo skills were evaluated. All of the training and probe sessions were conducted in the participants' classrooms or homes. Results of a multiple baseline design across subjects and skill components indicated that the performance of all children improved as a function of training. Skill maintenance was demonstrated by all participants during follow-up assessments conducted 2 to 6 weeks posttraining. Results of a questionnaire completed by caregivers and interviews with the children revealed high levels of satisfaction with the training procedures and outcomes.

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.

Communication skills training for parents: experimental and social validation.

Coordination of professional services of behalf of children often hinges on the involvement of informed parents. The purposes of this study were to identify and experimentally and socially validate skills required of parents for effective communication with professionals. Target skills were identified on the basis of judges' social validation ratings of (a) sample interactions between parents and professionals and (b) the behaviors comprising a resultant task analysis. Eight parents were then trained in these skills via an instructional package. Results of a multiple baseline design across subjects and grouped skill domains showed that each parent acquired the targeted skills during simulated conferences and that correct responding usually generalized to actual conferences. Independent judges validated training outcomes, and participating parents indicated satisfaction with the curriculum.

Behavioral management of oral medication administration difficulties among children: a review of literature with case illustrations.

Nonacceptance of prescribed oral medications among young children hinders medical treatment. The literature pertaining to teaching children how to swallow pills or capsules is reviewed. In addition, a multiple case study demonstrating the efficacy of a brief, easy-to-implement procedure designed to promote capsule acceptance is presented. In this study, two four-year-old children diagnosed to have chronic illnesses participated. In Case 1, use of verbal instruction, modeling, shaping, and contingent reinforcement resulted in the rapid acquisition of capsule swallowing skills. In Case 2, these training procedures, in combination with physical guidance contingent upon noncompliance, successfully produced repeated acceptance of medication by a child who had refused to swallow capsules. In both cases, compliance has been maintained for at least six months.