Biomedical subjects

Christopher Wyatt

Publications and source records attributed to Christopher Wyatt.

5 recordsLinked to original sources

PubMed2006

Minimum reliable scale selection in 3D.

Multiscale analysis is often required in image processing applications because image features are optimally detected at different levels of resolution. With the advance of high-resolution 3D imaging, the extension of multiscale analysis to higher dimensions is necessary. This paper extends an existing 2D scale selection method, known as the minimum reliable scale, to 3D volumetric images. The method is applied to 3D boundary detection and is illustrated in examples from biomedical imaging. The experimental results show that the 3D scale selection improves the detection of edges over single scale operators using as few as three different scales.

Algorithms↗

PubMed2005

Neuroimaging of rodent and primate models of alcoholism: initial reports from the integrative neuroscience initiative on alcoholism.

Neuroimaging of animal models of alcoholism offers a unique path for translational research to the human condition. Animal models permit manipulation of variables that are uncontrollable in clinical, human investigation. This symposium, which took place at the annual meeting of the Research Society on Alcoholism in Vancouver, British Columbia, Canada, on June 29th, 2004, presented initial findings based on neuroimaging studies from the two centers of the Integrative Neuroscience Initiative on Alcoholism funded by the National Institute on Alcohol Abuse and Alcoholism. Effects of alcohol exposure were assessed with in vitro glucose metabolic imaging of rat brain, in vitro receptor imaging of monkey brain, in vivo magnetic resonance imaging of monkey brain, and in vivo magnetic resonance spectroscopic quantification of alcohol metabolism kinetics in rat brain.

Alcoholism↗

PubMed2005

Does simulator training for medical students change patient opinions and attitudes toward medical student procedures in the emergency department?

OBJECTIVES: To determine how simulator training impacts patients' preferences about medical student procedures in the emergency department. METHODS: A questionnaire was administered to a convenience sample of 151 of 185 patients approached (82% participation) seen in the emergency department of a midwestern teaching hospital. The questionnaire asked how many procedures they would prefer a medical student have performed after mastering the procedure on a simulator before allowing the medical student to perform this procedure on them. The procedures included venipuncture, placement of an intravenous line, suturing the face or arm, performing a lumbar puncture, placement of a central line, placement of a nasogastric tube, intubation, and cardioversion. These results were compared with those of a similar study asking about the same procedures without the stipulation that the skill had been mastered on a simulator. RESULTS: A high of 57% (venipuncture) and a low of 11% (placement of a central line) would agree to be a student's first procedure after simulator training. Except for intubating and suturing, participants were more likely (p < 0.05) to allow a medical student to perform a procedure on them after simulator training than without simulator training. Many patients prefer not to have a medical student perform a procedure no matter how many procedures the student has done (low of 21% for venipuncture, high of 55% for placement of a central line). CONCLUSIONS: Patients are more accepting of medical students performing procedures if the skill has been mastered on a simulator. However, many patients do not want a medical student to perform a procedure on them regardless of the student's level of training.

Adolescent↗

PubMed2003

Genomic sequence of a ranavirus (family Iridoviridae) associated with salamander mortalities in North America.

Disease is among the suspected causes of amphibian population declines, and an iridovirus and a chytrid fungus are the primary pathogens associated with amphibian mortalities. Ambystoma tigrinum virus (ATV) and a closely related strain, Regina ranavirus (RRV), are implicated in salamander die-offs in Arizona and Canada, respectively. We report the complete sequence of the ATV genome and partial sequence of the RRV genome. Sequence analysis of the ATV/RRV genomes showed marked similarity to other ranaviruses, including tiger frog virus (TFV) and frog virus 3 (FV3), the type virus of the genus Ranavirus (family Iridoviridae), as well as more distant relationships to lymphocystis disease virus, Chilo iridescent virus, and infectious spleen and kidney necrosis virus. Putative open reading frames (ORFs) in the ATV sequence identified 24 genes that appear to control virus replication and block antiviral responses. In addition, >50 other putative genes, homologous to ORFs in other iridoviral genomes but of unknown function, were also identified. Sequence comparison performed by dot plot analysis between ATV and itself revealed a conserved 14-bp palindromic repeat within most intragenic regions. Dot plot analysis of ATV vs RRV sequences identified several polymorphisms between the two isolates. Finally, a comparison of ATV and TFV genomic sequences identified genomic rearrangements consistent with the high recombination frequency of iridoviruses. Given the adverse effects that ranavirus infections have on amphibian and fish populations, ATV/RRV sequence information will allow the design of better diagnostic probes for identifying ranavirus infections and extend our understanding of molecular events in ranavirus-infected cells.

Animals↗

PubMed2002

Response to direct and indirect recruitment for a randomised dental clinical trial in a multicultural population of elders.

OBJECTIVES: Recruitment for randomised clinical trials and community-based studies has received little attention in the dental literature. The goal of this study was to report on our experiences with direct and indirect recruitment methods for a trial to prevent tooth loss in elders. METHODS: A direct approach, consisting of an introductory lecture with the help of a local contact person in each of the nine community centres, resulted in 208 recruits mostly from minority non-English speaking communities (52%), whereas the other 192 recruits who responded to newspaper announcements (48%) were, in large part, from the English-speaking community. RESULTS: The response suggests that a more direct and culturally specific approach is more productive when recruiting elders from ethnic minority groups, whereas elders from the dominant culture can be recruited indirectly and for about half the financial cost through newspaper announcements. CONCLUSION: We conclude, therefore, that both direct and indirect methods are needed to recruit a multiethnic sample of subjects for a trial.

Aged↗