Browsing by Author "McAteer, James A."

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    4539 Building a Translational Science pipeline: The Indiana CTSI STEM K-12 Program
    (Cambridge University Press, 2020-07-29) Sanders, Elmer; Barth, Vanessa; Cruz, Leigh-Ann; Sherrer, Ilesha; Olson, Jacob; Speidell, Emily; Solis, Elvia; Harrison, Sharon; Hinshaw, Amy; McAteer, James A.; Anatomy, Cell Biology and Physiology, School of Medicine
    OBJECTIVES/GOALS: Develop strong network of science teachers interested in promoting scientific research to their students. Place students in an immersive summer research internship that, when possible, matches their career interests. Expose students to the numerous career paths within the STEM field. METHODS/STUDY POPULATION: The program recruits socio-economically disadvantaged students and provides them a stipend, and also accepts students who can participate unpaid. Local school teachers are engaged in a summer fellowship to learn biotechnologies and research. In Spring these teachers help recruit students and during the subsequent Fall help students with college and scholarship applications. Students are placed in a variety of laboratories within the Schools of Medicine, Science, Dentistry, Public Health, Informatics, Health and Human Sciences, Engineering and Technology, especially in biomedical engineering. Students are also placed in industry laboratories such as Eli Lilly and the Indiana Bioscience Research Institute. Long-term program follow-up is done through post-internship surveys to assess impact on graduate and professional school admission. RESULTS/ANTICIPATED RESULTS: Since the Indiana CTSI was established in 2008, 872 students have participated in the summer internship. 71% of past interns are underrepresented minorities in science or classified as disadvantaged by NIH criteria. 17% of students interned during grade 10, 72% during grade 11, and 11% during grade 12. 21% of students engage in the program for more than one year. 100% of past interns are currently enrolled in or have graduated college. Over 60% of those with a bachelors degree proceed to graduate and professional schools and over 80% stay in STEM related fields. These rates are equal for interns from underrepresented minorities or those classified as disadvantaged by NIH criteria. DISCUSSION/SIGNIFICANCE OF IMPACT: Students engaged in the Indiana CTSI STEM program are progressing through the translational science pipeline based on their graduating from college and remaining in the STEM field.
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    Effect of the body wall on lithotripter shock waves
    (Mary Ann Liebert, Inc., 2014-04) Li, Guangyan; McAteer, James A.; Williams, James C Jr.; Berwick, Zachary C.; Department of Anatomy & Cell Biology, IU School of Medicine
    PURPOSE: Determine the influence of passage through the body wall on the properties of lithotripter shock waves (SWs) and the characteristics of the acoustic field of an electromagnetic lithotripter. METHODS: Full-thickness ex vivo segments of pig abdominal wall were secured against the acoustic window of a test tank coupled to the lithotripter. A fiber-optic probe hydrophone was used to measure SW pressures, determine shock rise time, and map the acoustic field in the focal plane. RESULTS: Peak positive pressure on axis was attenuated roughly proportional to tissue thickness-approximately 6% per cm. Irregularities in the tissue path affected the symmetry of SW focusing, shifting the maximum peak positive pressure laterally by as much as ∼2 mm. Within the time resolution of the hydrophone (7-15 ns), shock rise time was unchanged, measuring ∼17-21 ns with and without tissue present. Mapping of the field showed no effect of the body wall on focal width, regardless of thickness of the body wall. CONCLUSIONS: Passage through the body wall has minimal effect on the characteristics of lithotripter SWs. Other than reducing pulse amplitude and having the potential to affect the symmetry of the focused wave, the body wall has little influence on the acoustic field. These findings help to validate laboratory assessment of lithotripter acoustic field and suggest that the properties of SWs in the body are much the same as have been measured in vitro.
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    Focused ultrasound to displace renal calculi: threshold for tissue injury
    (Springer Nature, 2014-03-31) Wang, Yak-Nam; Simon, Julianna C.; Cunitz, Bryan W.; Starr, Frank L.; Paun, Marla; Liggitt, Denny H.; Evan, Andrew P.; McAteer, James A.; Liu, Ziyue; Dunmire, Barbrina; Bailey, Michael R.; Anatomy, Cell Biology and Physiology, School of Medicine
    Background: The global prevalence and incidence of renal calculi is reported to be increasing. Of the patients that undergo surgical intervention, nearly half experience symptomatic complications associated with stone fragments that are not passed and require follow-up surgical intervention. In a clinical simulation using a clinical prototype, ultrasonic propulsion was proven effective at repositioning kidney stones in pigs. The use of ultrasound to reposition smaller stones or stone fragments to a location that facilitates spontaneous clearance could therefore improve stone-free rates. The goal of this study was to determine an injury threshold under which stones could be safely repositioned. Methods: Kidneys of 28 domestic swine were treated with exposures that ranged in duty cycle from 0%-100% and spatial peak pulse average intensities up to 30 kW/cm(2) for a total duration of 10 min. The kidneys were processed for morphological analysis and evaluated for injury by experts blinded to the exposure conditions. Results: At a duty cycle of 3.3%, a spatial peak intensity threshold of 16,620 W/cm(2) was needed before a statistically significant portion of the samples showed injury. This is nearly seven times the 2,400-W/cm(2) maximum output of the clinical prototype used to move the stones effectively in pigs. Conclusions: The data obtained from this study show that exposure of kidneys to ultrasonic propulsion for displacing renal calculi is well below the threshold for tissue injury.
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    High carbonate level of apatite in kidney stones underlines infection, but is it predictive?
    (Springer, 2013) Englert, Kate M.; McAteer, James A.; Lingeman, James E.; Williams, James C., Jr.; Anatomy, Cell Biology and Physiology, School of Medicine
    The presence of infectious microorganisms in urinary stones is commonly inferred from stone composition, especially by the presence of struvite in a stone. The presence of highly carbonated apatite has also been proposed as a marker of the presence of bacteria within a stone. We retrospectively studied 368 patients who had undergone percutaneous nephrolithotomy (PCNL), and who also had culture results for both stone and urine. Urine culture showed no association with stone mineral content, but stone culture was more often positive in struvite-containing stones (73 % positive) and majority apatite stones (65 %) than in other stone types (54 %, lower than the others, P < 0.02). In 51 patients in whom the carbonate content of apatite could be measured, carbonate in the apatite was weakly predictive of positive stone culture with an optimal cutoff value of 13.5 % carbonate (sensitivity 0.61, specificity 0.80). In positive cultures of stones (all mineral types combined), organisms that characteristically produce urease were present in 71 % of the cases, with no difference in this proportion among different types of stone. In summary, the type of mineral in the stone was predictive of positive stone culture, but this correlation is imperfect, as over half of non-struvite, non-apatite stones were found to harbor culturable organisms. We conclude that mineral type is an inadequate predictor of whether a stone contains infectious organisms, and that stone culture is more likely to provide information useful to the management of patients undergoing PCNL.
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    In vitro evaluation of the Lithoclast Ultra Vario combination lithotrite
    (Springer, 2010-12) VonDerHaar, Jonathan N.; McAteer, James A.; Williams, James C., Jr.; Lingeman, James E.; Anatomy and Cell Biology, School of Medicine
    Rigid intracorporeal lithotrites can be invaluable in the removal of large stone burdens during percutaneous nephrolithotomy. One such device, the Lithoclast Ultra Vario (LUV) has an outer ultrasound probe and inner pneumatic-ballistic probe. The ballistic probe can be advanced or retracted and run at 1-12 Hz. Since it can be difficult to predict optimal settings with any new device, we asked if in vitro testing could give insight into how best to operate this lithotrite. We tested the LUV under hands-free conditions that simulate treatment of fixed stones and freely movable stones. A fixed-stone test system measured the time to penetrate a gypsum model stone placed atop the probe and a movable-stone system determined time for comminution of a stone within a confined space. In addition, the time to evacuate 2-mm stone particles was measured. For hands-on testing, model stones were placed in a plastic dish submerged in water and the time to comminution was measured. Penetration time of fixed stones was faster with the ballistic probe extended 2.5 mm than when retracted (5.30 ± 0.85 vs. 8.75 ± 1.07 s, p < 0.0001). Comminution of free stones was faster with the ballistic probe retracted than when it was extended 1 mm or 2.5 mm (9.7 ± 0.9, 13.8 ± 1.3, 23.7 ± 3.2 s, p < 0.0001). In hands-on testing, extending the ballistic probe substantially reduced the efficiency of comminution (36.7 ± 6.4 vs. 131.3 ± 15.3 s, p < 0.0001). Clearance of fragments was considerably faster when the pneumatic-ballistic rate was 12 Hz compared to 1 Hz (12.3 ± 1.1 vs. 28.3 ± 2.2 s, p < 0.0001). These in vitro findings suggest ways to take advantage of the positive features while minimizing potential limitations of this lithotrite. Extending the ballistic probe is an advantage when the stone is immobile, as would be the case in treating a large stone that can be isolated against the wall of the pelvicalyceal system, but is a distinct disadvantage--due to retropulsion--when the stone is free to move. Operation of the LUV at fast ballistic rate significantly improved its ability to aspirate stone fragments.
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    Retention and growth of urinary stones: insights from imaging
    (Springer, 2013-01) Williams, James C., Jr.; McAteer, James A.; Medicine, School of Medicine
    Recent work in nephrolithiasis has benefited from 2 special kinds of imaging: endoscopic study of patient kidneys with high-quality instruments, and examination of stones with microscopic computed tomography (micro CT). The combination of these has provided new evidence that there is more than 1 mechanism by which stones are retained in the kidney until they achieve sizes to be clinically relevant. This review describes what is known about the formation of stones on Randall's plaque, the formation of stones on ductal plugs and the ways in which stones may grow in free solution within the calyceal or pelvic spaces. Studies of urolithiasis need to recognize that any group of "stone formers" likely includes patients who differ fundamentally regarding which mechanism of stone formation is the primary route for their stones. Separation of patients on the basis of which mechanism (or combination of mechanisms) underlies their disease will be important for advancing research in the area of urolithiasis.