Biomedical subjects

Kevin Kim

Publications and source records attributed to Kevin Kim.

7 recordsLinked to original sources

PubMed2026

Standardized visual overlays enhance laparoscopic instruction: A mixed-methods evaluation.

Effective communication during laparoscopic procedures is frequently undermined by spatial disorientation and inconsistent terminology between instructors and trainees. This study examined whether standardized visual overlays on endoscopic monitors could enhance communication and learning. We conducted a three-phase mixed-methods study: qualitative observation of 20 laparoscopic teaching cases; a randomized trial of 63 second-year medical students assigned to control, clock, or alphanumeric grid (AG) overlays during three trials of a standardized transfer task; and intraoperative implementation in 44 cases (30 AG, 14 clock) with post-case surveys and qualitative feedback. In simulation, the clock overlay produced the fastest completion times, whereas the AG yielded the lowest error scores, and both overlays outperformed the control. Intraoperatively, the AG was rated higher than the clock for communication clarity, spatial orientation, perceived operative efficiency, and trainee confidence. Standardized visual overlays, particularly the AG, appear to support intraoperative teaching by providing a shared spatial frame of reference.

Laparoscopy↗

PubMed2006

Conversion of pre-RISC to holo-RISC by Ago2 during assembly of RNAi complexes.

In the Drosophila RNA interference (RNAi) pathway, small interfering RNAs (siRNAs) direct Argonaute2 (Ago2), an endonuclease, within the RNA-induced silencing complex (RISC) to cleave complementary mRNA targets. In vitro studies have shown that, for each siRNA duplex, RISC retains only one strand, the guide, and releases the other, the passenger, to form a holo-RISC complex. Here, we have isolated a new Ago2 mutant allele and provide, for the first time, in vivo evidence that endogenous Ago2 slicer activity is important to mount an RNAi response in Drosophila. We demonstrate in vivo that efficient removal of the passenger strand from RISC requires the cleavage activity of Ago2. We have also identified a new intermediate complex in the RISC assembly pathway, pre-RISC, in which Ago2 is stably bound to double-stranded siRNA.

Alleles↗

PubMed2006

RNA interference directs innate immunity against viruses in adult Drosophila.

Innate immunity against bacterial and fungal pathogens is mediated by Toll and immune deficiency (Imd) pathways, but little is known about the antiviral response in Drosophila. Here, we demonstrate that an RNA interference pathway protects adult flies from infection by two evolutionarily diverse viruses. Our work also describes a molecular framework for the viral immunity, in which viral double-stranded RNA produced during infection acts as the pathogen trigger whereas Drosophila Dicer-2 and Argonaute-2 act as host sensor and effector, respectively. These findings establish a Drosophila model for studying the innate immunity against viruses in animals.

Animals↗

PubMed2006

Ecological validity of neuropsychological assessment and perceived employability.

Ecological validity studies that have examined the relationship between cognitive abilities and employment in psychiatric and medical populations have found that a wide range of cognitive domains predict employability, although memory and executive skills appear to be the most important. However, no information is available regarding a patient's self-perceived work attributes and objective neuropsychological performance, and whether the same cognitive domains associated with successful employment are also related to a patient's self-perception of work competence. In the present study, 73 medical and psychiatric patients underwent comprehensive neuropsychological assessment. Step-wise multiple regression analyses revealed that the visual-spatial domain was the only significant predictor of self-perceived work attributes and work competence as measured by the Working Inventory (WI) and the Work Adjustment Inventory (WAI), accounting for 7% to 10% of inventory score variability. The results raise the intriguing possibility that targeting of visual spatial skills for remediation and development might play a separate and unique role in the vocational rehabilitation of a lower SES population, specifically, by leading to enhanced self-perception of work competence as these individuals attempt to enter the job market.

Adult↗

PubMed2005

Targets of microRNA regulation in the Drosophila oocyte proteome.

MicroRNAs (miRNAs) are a class of small RNAs that silence gene expression. In animal cells, miRNAs bind to the 3' untranslated regions of specific mRNAs and inhibit their translation. Although some targets of a handful of miRNAs are known, the number and identities of mRNA targets in the genome are uncertain, as are the developmental functions of miRNA regulation. To identify the global range of miRNA-regulated genes during oocyte maturation of Drosophila, we compared the proteome from wild-type oocytes with the proteome from oocytes lacking the dicer-1 gene, which is essential for biogenesis of miRNAs. Most identified proteins appeared to be subject to translation inhibition. Their transcripts contained putative binding sites in the 3' untranslated region for a subset of miRNAs, based on computer modeling. The fraction of genes subject to direct and indirect repression by miRNAs during oocyte maturation appears to be small (4%), and the genes tend to share a common functional relationship in protein biogenesis and turnover. The preponderance of genes that control global protein abundance suggests this process is under tight control by miRNAs at the onset of fertilization.

3' Untranslated Regions↗

PubMed2004

Distinct roles for Drosophila Dicer-1 and Dicer-2 in the siRNA/miRNA silencing pathways.

The RNase III enzyme Dicer processes RNA into siRNAs and miRNAs, which direct a RNA-induced silencing complex (RISC) to cleave mRNA or block its translation (RNAi). We have characterized mutations in the Drosophila dicer-1 and dicer-2 genes. Mutation in dicer-1 blocks processing of miRNA precursors, whereas dicer-2 mutants are defective for processing siRNA precursors. It has been recently found that Drosophila Dicer-1 and Dicer-2 are also components of siRNA-dependent RISC (siRISC). We find that Dicer-1 and Dicer-2 are required for siRNA-directed mRNA cleavage, though the RNase III activity of Dicer-2 is not required. Dicer-1 and Dicer-2 facilitate distinct steps in the assembly of siRISC. However, Dicer-1 but not Dicer-2 is essential for miRISC-directed translation repression. Thus, siRISCs and miRISCs are different with respect to Dicers in Drosophila.

Animals↗

PubMed2004

MRI guidance of focused ultrasound therapy of uterine fibroids: early results.

OBJECTIVE: The purpose of this study was to explore our hypothesis that MRI-guided focused ultrasound therapy for the treatment of uterine fibroids will lead to a significant reduction in symptoms and improvement in quality of life. We describe focused ultrasound therapy applications and the method for monitoring the thermal energy deposited in the fibroids, including the MRI parameters required, in a prospective review of 108 treatments. MATERIALS AND METHODS: Patients presenting with symptomatic uterine fibroids who attained a minimal symptom severity score and who would otherwise have been offered a hysterectomy were recruited. Thermal lesions were created within target fibroids using an MRI-guided focused ultrasound therapy system. The developing lesion was monitored using real-time MR thermometry, which was used to assess treatment outcome in real time to change treatment parameters and achieve the desired outcome. Fibroid volume, fibroid symptoms, and quality-of-life scores were measured before treatment and 6 months after treatment. Adverse events were actively monitored and recorded. RESULTS: In this study, 79.3% of women who had been treated reported a significant improvement in their uterine fibroid symptoms on follow-up health-related quality-of-life questionnaires, which supports our hypothesis. The mean reduction in fibroid volume at 6 months was 13.5%, but nonenhancing volume (mean, 51 cm(3)) remained within the treated fibroid at 6 months. CONCLUSION: This early description of MRI-guided focused ultrasound therapy treatment of fibroids includes follow-up data and shows that, although the volume reduction is moderate, it correlates with treatment volume and the symptomatic response to this treatment is encouraging.

Adult↗