An investigation of the relationship between antemortem and postmortem drug concentrations in blood

In the field of postmortem toxicology, principles from pharmacology and toxicology are combined in order to determine if exogenous substances contributed to ones death. In order to make this determination postmortem and (whenever available) antemortem blood samples may be analyzed. This project focused on evaluating the relationship between postmortem and antemortem blood drug levels, in order to better define an interpretive framework for postmortem toxicology. To do this, it was imperative to evaluate the differences in antemortem and postmortem drug concentrations, determine the role microbial activity and evaluate drug stability. Microbial studies determined that the bacteria Escherichia coli and Pseudomonas aeruginosa could use the carbon structures of drugs as a source of food. This would suggest prior to sample collection, microbial activity could potentially affect drug levels. This process however would stop before toxicologic evaluation, as at autopsy blood samples are stored in tubes containing the antimicrobial agent sodium fluoride. Analysis of preserved blood determined that under the current storage conditions sodium fluoride effectively inhibited microbial growth. Nonetheless, in many instances inconsistent drug concentrations were identified. When comparing antemortem to postmortem results, diphenhydramine, morphine, codeine and methadone, all showed significantly increased postmortem drug levels. In many instances, increased postmortem concentrations correlated with extended postmortem intervals. Other drugs, such as alprazolam, were likely to have concentration discrepancies when short antemortem to death intervals were coupled with extended postmortem intervals. While still others, such as midazolam followed the expected pattern of metabolism and elimination, which often resulted in decreased postmortem concentrations. The importance of drug stability was displayed when reviewing the clonazepam/ 7-aminoclonazepam data, as the parent drug commonly converted to its metabolite even when stored in the presence of a preservative. In instances of decreasing postmortem drug concentrations the effect of refrigerated storage could not be ruled out. A stability experiment, which contained codeine, produced data that indicated concentrations could continue to decline under the current storage conditions. The cumulative data gathered for this experiment was used to identify concentration trends, which subsequently aided in the development of interpretive considerations for the specific analytes examined in the study.

The effectiveness of explicit individualized phonemic awareness instruction by a speech -language pathologist to preschool children with phonological speech disorders

This study investigated the effects of an explicit individualized phonemic awareness intervention administered by a speech-language pathologist to 4 prekindergarten children with phonological speech sound disorders. Research has demonstrated that children with moderate-severe expressive phonological disorders are at-risk for poor literacy development because they often concurrently exhibit weaknesses in the development of phonological awareness skills (Rvachew, Ohberg, Grawburg, & Heyding, 2003).^ The research design chosen for this study was a single subject multiple probe design across subjects. After stable baseline measures, the participants received explicit instruction in each of the three phases separately and sequentially. Dependent measures included same-day tests for Phase I (Phoneme Identity), Phase II (Phoneme Blending), and Phase III (Phoneme Segmentation), and generalization and maintenance tests for all three phases.^ All 4 participants made substantial progress in all three phases. These skills were maintained during weekly and biweekly maintenance measures. Generalization measures indicated that the participants demonstrated some increases in their mean total number of correct responses in Phase II and Phase III baseline while the participants were in Phase I intervention, and more substantial increases in Phase III baseline while the participants were in Phase II intervention. Increased generalization from Phases II to III could likely be explained due to the response similarities in those two skills (Cooper, Heron, & Heward, 2007).^ Based upon the findings of this study, speech-language pathologists should evaluate phonological awareness in the children in their caseloads prior to kindergarten entry, and should allocate time during speech therapy to enhance phonological awareness and letter knowledge to support the development of both skills concurrently. Also, classroom teachers should collaborate with speech-language pathologists to identify at-risk students in their classrooms and successfully implement evidence-based phonemic awareness instruction. Future research should repeat this study including larger groups of children, children with combined speech and language delays, children of different ages, and ESOL students.^

The Effectiveness of Explicit Individualized Phonemic Awareness Instruction By a Speech-Language Pathologist to Preschool Children With Phonological Speech Disorders

This study investigated the effects of an explicit individualized phonemic awareness intervention administered by a speech-language pathologist to 4 prekindergarten children with phonological speech sound disorders. Research has demonstrated that children with moderate-severe expressive phonological disorders are at-risk for poor literacy development because they often concurrently exhibit weaknesses in the development of phonological awareness skills (Rvachew, Ohberg, Grawburg, & Heyding, 2003). The research design chosen for this study was a single subject multiple probe design across subjects. After stable baseline measures, the participants received explicit instruction in each of the three phases separately and sequentially. Dependent measures included same-day tests for Phase I (Phoneme Identity), Phase II (Phoneme Blending), and Phase III (Phoneme Segmentation), and generalization and maintenance tests for all three phases. All 4 participants made substantial progress in all three phases. These skills were maintained during weekly and biweekly maintenance measures. Generalization measures indicated that the participants demonstrated some increases in their mean total number of correct responses in Phase II and Phase III baseline while the participants were in Phase I intervention, and more substantial increases in Phase III baseline while the participants were in Phase II intervention. Increased generalization from Phases II to III could likely be explained due to the response similarities in those two skills (Cooper, Heron, & Heward, 2007). Based upon the findings of this study, speech-language pathologists should evaluate phonological awareness in the children in their caseloads prior to kindergarten entry, and should allocate time during speech therapy to enhance phonological awareness and letter knowledge to support the development of both skills concurrently. Also, classroom teachers should collaborate with speech-language pathologists to identify at-risk students in their classrooms and successfully implement evidence-based phonemic awareness instruction. Future research should repeat this study including larger groups of children, children with combined speech and language delays, children of different ages, and ESOL students