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Biomedical subjects

Patrick O'Neill

Publications and source records attributed to Patrick O'Neill.

10 recordsLinked to original sources
PubMed2006

Relationships between self-assessment skills, test performance, and demographic variables in psychiatry residents.

Some researchers have seen the capacity for self-assessment in trainees as a special skill, and some reports have concluded that this skill is positively and crucially correlated with academic competence. Thus, it is believed that those trainees who are most deficient in knowledge are least likely to be aware of their limitations. Other researchers have emphasized the impact of statistical regression and other technical considerations in the studies, which have led to these conclusions. Our study used a relative-ranking design to measure the accuracy of self-assessments of both strengths and weaknesses in psychiatry residents. We analyzed the relationships between indices of self-assessment accuracy and other resident characteristics, particularly current academic strength as measured by a standard test of psychiatric knowledge. A total of 56 residents in two general psychiatry programs evaluated their performance on the Psychiatry Resident in Training Examination by estimating the rank order of their scores in the 11 psychiatry subject areas. For each resident, actual examination results were then used to generate measures of the accuracy of the identification of strengths and weaknesses. Residents' identifications of their strengths and weaknesses were significantly more accurate than chance levels. Strengths and weaknesses were identified with roughly equal proficiency, and accuracy in these assessments was not correlated to any of the following variables: academic competence as measured by examination raw scores, postgraduate year, gender, international vs. American medical education, program membership, or age. Our results do not support the hypothesis that trainees who show the least academic mastery also make the most inaccurate self-assessments. In addition, we found no resident characteristics that accounted for variation in self-assessment accuracy.

Age Factors↗
PubMed2006

Sturdier DNA nanotubes via ligation.

DNA nanotubes are crystalline self-assemblies of DNA tiles approximately 10 nm in diameter that readily grow tens of micrometers in length. Easy assembly, programmability, and stiffness make them interesting for many applications, but DNA nanotubes begin to melt at temperatures below 40 degrees C, break open when deposited on mica or scanned by AFM, and disintegrate in deionized water. These weaknesses can be traced to the presence of discontinuities in the phosphate backbone, called nicks. The nanotubes studied here have five nicks, one in the core of a tile and one at each corner. We report the successful ligation of all four corner nicks by T4 DNA ligase. Although ligation does not change the nanotubes' stiffness, ligated nanotubes withstand temperatures over 70 degrees C, resist breaking during AFM, and are stable in pure water for over a month. Ligated DNA nanotubes are thus physically and chemically sturdy enough to withstand the manipulations necessary for many technological applications.

Aluminum Silicates↗
PubMed2005

Secondary cleft sign as a marker of injury in athletes with groin pain: MR image appearance and interpretation.

PURPOSE: To determine whether the secondary cleft sign demonstrated in the symphysis pubis at magnetic resonance (MR) imaging is a marker of injury in athletes presenting with groin pain. MATERIALS AND METHODS: Ethics review board approval was not required for studies involving retrospective image or case record review; informed consent for review was not required. Eighteen male athletes (mean age, 24 years; age range, 19-32 years) were included for study. All patients underwent radiography and MR imaging (coronal fast spin-echo T1-weighted, transverse fast spin-echo T2-weighted, and coronal turbo short inversion time inversion-recovery [STIR] imaging) of the pelvis. Subsequent image-guided nonionic contrast material injection was followed by a 0.5% bupivacaine hydrochloride (1 mL) and methyprednisolone acetate (20 mg) injection into the central cleft of the symphysis pubis. Comparison was made between imaging findings at symphyseal cleft injection and appearances at preprocedure MR imaging, with specific reference to the presence of a secondary cleft. The sensitivity and specificity of MR imaging in demonstrating the secondary cleft sign were compared with those of the reference standard, imaging at symphyseal cleft injection. MR images from a reference group of 70 asymptomatic athletes who underwent STIR imaging of the pelvis were analyzed for evidence of a secondary cleft. RESULTS: Osteitis pubis was diagnosed in six patients on the basis of radiography and/or MR imaging. A secondary cleft was identified in 12 of 18 patients at MR imaging, was best visualized at coronal STIR imaging, and was confirmed in each patient during contrast material injection into the central physiologic symphyseal cleft. In no patient was a secondary cleft identified at symphyseal cleft injection and not identified at MR imaging (sensitivity and specificity, 100%). In each patient, the side of the secondary cleft corresponded to the side of symptoms that responded to local anesthetic and steroid injection. Four of the six patients with osteitis pubis had evidence of a secondary cleft. In one patient, a secondary cleft was not identified at MR imaging or symphyseal cleft injection, but adductor avulsion was identified at MR imaging. No evidence of a secondary cleft sign at MR imaging was identified in the reference group. CONCLUSION: The secondary cleft sign demonstrated at MR imaging is a marker of groin injury in athletes presenting with groin pain.

Adult↗
PubMed2005

In vitro studies of the genotoxicity of ionizing radiation in human G(0) T lymphocytes.

In an effort to mimic human in vivo exposures to ionizing irradiation, G(0) phase T lymphocytes from human peripheral blood samples were utilized for in vitro studies of the genotoxic effects of (137)Cs low-LET irradiation and (222)Rn high-LET irradiation. Both types of radiation induced mutations in the HPRT gene in a dose-dependent manner, with a mutant frequency (MF) = 4.28 + 1.34x + 7.51x(2) for (137)Cs (R(2) = 0.95) and MF = 4.81 + 0.67x for (222)Rn (R(2) = 0.51). Post (137)Cs irradiation incubation in the presence of cytosine arabinoside, a reversible inhibitor of DNA repair, caused an increase in the MF over irradiation alone, consistent with a misrepair mechanism being involved in the mutagenicity of low-LET irradiation. The spectrum of (137)Cs irradiation-induced mutation displayed an increase in macro-deletions (in particular total gene deletions) and rearrangement events, some of which were further defined by either chromosome painting or direct DNA sequencing. The spectrum of (222)Rn irradiation-induced mutation was characterized by an increase in small alterations, especially multiple single base deletions/substitutions and micro-deletions. These studies define the specific response of human peripheral blood T cells to ionizing irradiation in vitro and form a basis for evaluating the genotoxic effects of human in vivo exposure.

Cell Division↗
PubMed2004

Wave-number selection by target patterns and sidewalls in Rayleigh-Bénard convection.

We present experimental results for patterns of Rayleigh-Bénard convection in a cylindrical container with static sidewall forcing. The fluid used was methanol, with a Prandlt number sigma=7.17 , and the aspect ratio was Gamma identical withR/d approximately 19 ( R is the radius and d the thickness of the fluid layer). In the presence of a small heat input along the sidewall, a sudden jump of the temperature difference DeltaT from below to slightly above a critical value Delta T(c) produced a stable pattern of concentric rolls (a target pattern) with the central roll (the umbilicus) at the center of the cell. A quasistatic increase of epsilon identical withDeltaT/Delta T(c) -1 beyond epsilon(1,c) approximately 0.8 caused the umbilicus of the pattern to move off center. As observed by others, a further quasistatic increase of epsilon up to epsilon=15.6 caused a sequence of transitions at epsilon(i,b) ,i=1,...,8 , each associated with the loss of one convection roll at the umbilicus. Each loss of a roll was preceded by the displacement of the umbilicus away from the center of the cell. After each transition the umbilicus moved back toward but never quite reached the center. With decreasing epsilon new rolls formed at the umbilicus when epsilon was reduced below epsilon(i,a) < epsilon(i,b) . When decreasing epsilon , large umbilicus displacements did not occur. In addition to quantitative measurements of the umbilicus displacement, we determined and analyzed the entire wave-director field of each image. The wave numbers varied in the axial direction, with minima at the umbilicus and at the cell wall and a maximum at a radial position close to 2Gamma/3 . The wave numbers at the maximum showed hysteretic jumps at epsilon(i,b) and epsilon(i,a) , but on average agreed well with the theoretical predictions for the wave numbers selected in the far field of an infinitely extended target pattern. To our knowledge there is as yet no prediction for the wave number selected by the umbilicus itself, or by the cell wall of the finite experimental system.

Journal Article↗
PubMed2004

Repair of giant abdominal hernias: does the type of prosthesis matter?

Closure of the abdominal wall after trauma or major surgery may be difficult due to visceral edema or fascial weakness; thus, the risk of developing a ventral hernia (VH) is high. Commonly, these hernias are repaired using a prosthetic mesh. Complications following mesh repair can develop. We hypothesize that the type of prosthetic material affects outcome. This is a retrospective chart review of patients admitted from 1996 to 2002 undergoing VH (> or = 20 x 10 cm) repair with prosthetic mesh. Data collected included age, sex, and race. Patients were stratified by prosthetic material as follows: Gore-Tex (GR), Marlex + Gore-Tex (MG), Marlex (MR), and Marlex + Vicryl (MV). For the purpose of clinical analysis, the groups were collapsed into subgroups: Gore-Tex exposure (GT) or non-Gore-Tex exposure (NG). Outcome measures were hernia recurrence (HR), wound infection (WI), and fistula formation (FF). Statistical analysis utilized chi2 test and Fisher's exact test. There were 55 VH repairs in 37 patients. The mean age was 43.9 (+/- 16.3), males out-numbered females 22 (59.5%) to 15 (40.5%). The majority of the patients were Caucasian (29; 78.4%). There were 30 trauma patients (81.1%), and 7 general surgery patients (18.9%). The HR for the study (n = 55) was 20 (36.4%), the WI was 17 (30.9%), and the FF was 3 (5.5%). GR group (6; 66.7%) had a significant higher wound IF rate than MR group (8; 26.7%) (Chi P = 0.02, Fisher P = 0.047). All other group comparisons (HR, WI, and FF) were N.S. The Gore-Tex versus non-Gore-Tex subgroup comparison results were as follows: GT (n = 18) had a WI 8 (44.4%), HR 6 (33.3%), and FF 0 (0%). NG (n = 37) had a WI 9 (24.3%), HR 14 (37.8%), and a FF 3 (8.1%). There was a trend toward a higher wound infection in the GT versus NG, but it did not reach statistical significance. We conclude that 1) the wound infection rate was higher in the Gore-Tex versus the Marlex group (Chi P = 0.02, Fisher P = 0.047). Wound infection in the presence of Gore-Tex usually mandates the removal of the mesh resulting in a hernia recurrence. 2) There was a trend toward a higher wound infection in the GT (44.4%) versus NG (24.3%), but it did not reach statistical significance.

Academic Medical Centers↗
PubMed1992

What creates the dilemma in ethical dilemmas? Examples from psychological practice.

Twenty psychologists were interviewed about an ethical dilemma that they had found to be particularly difficult to resolve. In just under half of the cases the dilemma involved a perceived conflict of ethical principles (e.g., the welfare of the consumer vs. the right to privacy). In the other cases, the psychologists were prevented from following an ethically prescribed course of action by some nonethical consideration such as contractual obligation, legal requirement, or the demands of an employer. We discuss the implications of these two sorts of dilemmas for psychological practice and make some suggestions for proactive approaches to ethical problem solving.

Adolescent↗
PubMed1991

A systems approach to ethical problems.

Codes of professional ethics and cases designed to teach ethical decision making are written for individual professionals and ignore the systems level of analysis. They typically employ a lineal view of causality and overvalue placement of blame as a component of ethical problem solving. This article takes a systems approach to ethical problems and identifies aspects of systems that promote or impede ethical decision making. Psychological abuse of children is used as an example of a problem requiring a coordinated, systemic response to ethical issues such as autonomy, privacy, and confidentiality.

Child↗