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Biomedical subjects

Michael Larson

Publications and source records attributed to Michael Larson.

13 recordsLinked to original sources

Using movie clips in PowerPoint presentations: part 1, compatibility issues.

OBJECTIVE: The purpose of this article is to discuss common compatibility issues relating to the use of movie clips in PowerPoint presentations. CONCLUSION: Our investigations found that successful display of movie clips in PowerPoint depends on the following three factors: movie file format, codec selection, and cross-platform compatibility. These factors primarily result from the rapid change in today's computer operating systems. Based on a compatibility study of common movie clips used in radiology presentations, a general guideline for preparing movie clips is presented. Also, a simple method is described for converting movie clips into compatible movie formats and reducing large movie clips to manageable file sizes to ensure smooth presentation.

Motion Pictures↗

Using movie clips in PowerPoint presentations: part 2, movie editing.

OBJECTIVE: The purpose of this article is to describe a simple method for editing movie clips for PowerPoint presentations. CONCLUSION: We describe a simple method for editing movie clips using Adobe Photoshop, a common software utility used by many radiologists for preparing digital images.

Motion Pictures↗

A simple method for displaying cine images on web-based teaching files.

OBJECTIVE: Our objective was to develop a simple method for displaying dynamic cine images on Web-based teaching files. CONCLUSION: We developed a simple method for displaying cine images on Web-based teaching files using an open-source utility, the Java applet. This interactive utility offers improved 3D visualizations compared with the traditional approach using thumbnail and static images. Because Java is a built-in component of common Web browsers and computer systems, no other software was required. We have used this applet successfully for more than 2 years in our Web-based teaching system, including in our teaching files and on our case-of-the-week page.

Computer-Assisted Instruction↗

Comprehensive innovative solution for resident education using the Intranet Journal of Chest Radiology.

RATIONALE AND OBJECTIVES: Because of the rapid increase in clinical workload in academic radiology departments, time for teaching rotating residents is getting more and more limited. As a solution to this problem, we introduced the Intranet Journal of Chest Radiology as a comprehensive innovative tool for assisting resident education. MATERIALS AND METHODS: The Intranet Journal of Chest Radiology is constructed using Microsoft FrontPage version 2002 (Microsoft Corp, Redmond, WA) and is hosted in our departmental web server (Beth Israel Deaconess Medical Center, Boston, MA). The home page of the intranet journal provides access to the main features, "Cases of the Month," "Teaching File," "Selected Articles for Residents," "Lecture Series," and "Current Publications." These features provide quick access to the selected radiology articles, the interesting chest cases, and the lecture series and current publication from the chest section. RESULTS: Our intranet journal has been well utilized for 6 months after its introduction. It enhances residents' interest and motivation to work on case collections, to search and read articles, and to generate interest in research. Frequent updating is necessary for the journal to be kept current, relevant, and well-utilized. CONCLUSION: The intranet journal serves as a comprehensive innovative solution for resident education, providing basic educational resources and opportunities of interactive participation by residents.

Computer Communication Networks↗

Short tandem repeat analysis to monitor chimerism in macaca fascicularis.

Chimerism assessment following bone marrow transplantation (BMT) in cynomolgus monkeys (cynos) has been hampered by the lack of good engraftment markers. In human BMT, such markers have been provided by short tandem repeat (STR) loci. We tested the idea that techniques effective for detecting human STR could be readily adapted to cynos. Genomic DNA was extracted from cyno unseparated blood or peripheral cell subsets. With only slight modifications, reagents for detecting human STR alleles were used to amplify and detect cyno STRs and to quantitate allelic mixtures on an automated sequencer. Of the 15 STR loci tested, only CSF1PO, D18S51, and FGA successfully amplified, with seven, seven and two alleles, respectively. CSF1PO and D18S51 heterozygosity (80% and 55%, respectively) allowed use of these two loci for chimerism quantitation after BMT. The successful adaptation of human STR reagents to monitor chimerism in transplanted cynos will facilitate the use of this species in preclinical tolerance studies.

Animals↗

A simple method for extracting DICOM images from a magnetooptic disk.

OBJECTIVE: Our objective was to develop a simple and easy-to-use method to extract DICOM images from magnetooptic (MO) disks to the computer desktop for research purposes. CONCLUSION: The method we developed allows users to extract DICOM images directly from MO disks to a PC desktop. The hardware component that we used is commercially available and is plug-and-play. The system is lower in cost than a clinical workstation. Users do not need to have special computer skills to use our method. DICOM images can be transferred directly from the MO disks to computer desktop folders using drag-and-drop. In our implementation, we store the DICOM files in a shared folder in our hospital network, so users can access the data from their office or research computers.

Humans↗

A Web-based ACR index for radiological diagnoses.

OBJECTIVE: We created an online computer system that allows radiologists to access the American College of Radiology (ACR) index for radiologic diagnoses from any Web browser. CONCLUSION: A total of 11,260 indexes (10 anatomic, 722 pathologic, 90 subanatomic, and 10,438 subpathologic) were integrated into this online system. Users can navigate the entire ACR hierarchic indexing structure with easy-to-use cascading dropdown lists. This password-protected system also allows free-text searches, ACR index searches, and bookmark functions. We have used this system in our departmental intranet for more than 2 years.

Abstracting and Indexing↗

Prevention of organ allograft rejection by a specific Janus kinase 3 inhibitor.

Because of its requirement for signaling by multiple cytokines, Janus kinase 3 (JAK3) is an excellent target for clinical immunosuppression. We report the development of a specific, orally active inhibitor of JAK3, CP-690,550, that significantly prolonged survival in a murine model of heart transplantation and in cynomolgus monkeys receiving kidney transplants. CP-690,550 treatment was not associated with hypertension, hyperlipidemia, or lymphoproliferative disease. On the basis of these preclinical results, we believe JAK3 blockade by CP-690,550 has potential for therapeutically desirable immunosuppression in human organ transplantation and in other clinical settings.

Animals↗

Steady-state visual evoked potentials reveal frontally-mediated working memory activity in humans.

Steady-state visual evoked potentials (SSVEPs) reflect power changes at the stimulus driving frequency and have been used to assess brain activity reflecting cognitive processing. Only one study has demonstrated SSVEP modulation associated with working memory (WM), and none have compared the spatial localization of SSVEP modulations during WM performance with other brain imaging methods. Here we examined WM-related activity recorded with dense-array SSVEPs, analyzed using low resolution electromagnetic tomography, and compared the results to our previous findings using functional magnetic resonance imaging (fMRI). WM was associated with increased SSVEP activity over the right dorsolateral prefrontal cortex, paralleling our previous fMRI findings. Frontal WM-related SSVEP power correlated selectively with task performance. These results demonstrate the utility of SSVEPs for studying representational aspects of cognition.

Adolescent↗

A life-supporting technique of renal allotransplantation in Macaca fascicularis to evaluate novel immunosuppressive drugs in nonhuman primates.

BACKGROUND: The use of nonhuman primates in preclinical transplantation studies is becoming more common. This report details complete procedures developed for a successful life-supporting kidney allotransplantation program using the cynomolgus monkey (Macaca fascicularis). MATERIALS AND METHODS: All transplants were performed in wild-caught, ABO-matched, MLR-mismatched adult males. Transplant procedures were staggered: an animal first served as a donor, was allowed to recover for 4 weeks, and was subsequently used as a recipient. The kidney was flushed in situ while the aorta was briefly cross-clamped. The graft was implanted heterotopically end-to-side in the right iliac fossa using microsurgical techniques. An ureteroneocystostomy was constructed; a telemetry probe was inserted into the aorta, and the remaining native kidney was removed. RESULTS: Sixty-two transplants were performed in 6.9 +/- 0.1 kg animals. Operating times in the donor and recipient were 126 +/- 3 and 166 +/- 5 min, respectively. The cold ischemia time was 55 +/- 1 min. There were no intraoperative deaths. Postoperative complications were observed in six (9.7%) monkeys and consisted of one early renal arterial thrombosis and five ureteral complications (two of which were successfully repaired). Transplants were ultimately successful in 93.6% (58/62) of cases. Immediate kidney function was satisfactory, with a mean serum creatinine of 1.7 +/- 0.2 mg/dL and a mean urine output of 140 +/- 15 ml on postoperative day 7. CONCLUSION: Life-supporting kidney transplantation in cynomolgus macaques is a demanding operation that requires great attention to details. Precise surgical techniques, telemetric monitoring, ultrasound surveillance, and aggressive, early, postoperative fluid resuscitation produced a 94% success rate.

Animals↗

Acculturation to Western society as a risk factor for high blood pressure: a meta-analytic review.

OBJECTIVE: A number of studies have documented that acculturation to western society is related to an increase in blood pressure (BP). Although there is evidence that higher socioeconomic status appears related to better cardiovascular health, increasing acculturation to western society appears related to worse cardiovascular health. The purpose of this meta-analysis was to investigate the association between acculturation and BP. METHODS: Literature searches yielded 125 relevant research manuscripts, which were coded by teams of two independent raters. This study was conducted in 2003 and 2004, and research databases such as MEDLINE and PsychINFO were searched through 2004. Measures of association (effect sizes) were extracted for both systolic blood pressure (SBP) and diastolic blood pressure (DBP) readings. Random effects models were used to analyze the resulting data. RESULTS: The overall effect sizes associated with acculturation were 0.28 for SBP and 0.30 for DBP, with increasing acculturation to western society related to higher BP. More acculturated individuals had an average of 4 mm Hg higher BP than less acculturated individuals, which is similar to the effect sizes of known risk factors for high BP such as diet and physical activity. The effects of acculturation on BP appear to be universal, with similar effect sizes found across all regions of the world. Change in BP due to acculturation was not related to body mass index (BMI) or cholesterol but was related to length of residence in the new culture, with the largest effect sizes seen on initial entry and then decreasing rapidly within the first few years. Sudden cultural changes, such as migration from rural to urban settings, resulted in the largest effect sizes, which finding supports the hypothesis that the stress of cultural change is important role in the acculturation effect. CONCLUSIONS: Acculturation to western society is associated with higher BP, and the distress associated with cultural change appears to be more influential than changes in diet or physical activity. Future studies would benefit from investigating how cultural change affects health and examining whether some non-Western cultural values and practices are health protective.

Acculturation↗