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Browsing by Subject "Sus scrofa"
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Item 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 MedicinePURPOSE: 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.Item Percutaneous Renal Access: Surgical Factors Involved in the Acute Reduction of Renal Function(Mary Ann Liebert, Inc., 2016-02) Handa, Rajash K.; Johnson, Cynthia D.; Connors, Bret A.; Evan, Andrew P.; Lingeman, James E.; Liu, Ziyue; Department of Anatomy & Cell Biology, IU School of MedicineINTRODUCTION AND OBJECTIVE: Studies in patients and experimental animals have shown that percutaneous nephrolithotomy (PCNL) can acutely impair glomerular filtration and renal perfusion, but the factors contributing to this decline in renal function are unknown. The present study assessed the contribution of needle puncture of the kidney vs dilation of the needle tract to the acute decline in renal hemodynamic and tubular transport function associated with PCNL surgery. MATERIALS AND METHODS: Acute experiments were performed in three groups of anesthetized adult farm pigs: sham-percutaneous access (PERC), that is, no surgical procedure (n = 7); a single-needle stick to access the renal collecting system (n = 8); expansion of the single-needle access tract with a 30F NephroMax balloon dilator and insertion of a nephrostomy sheath (n = 10). The glomerular filtration rate (GFR), effective renal plasma flow (ERPF), and renal extraction of para-amino hippurate (EPAH, estimates tubular organic anion transporter [OAT] activity) were assessed before and 1 to 4.5 hours after sham-PERC or PERC surgical procedures. RESULTS: Overall, GFR responses were similar in all three groups. Sham-treated PERC pigs showed no significant change in ERPF over the experimental observation period, whereas a single-needle stick to access the renal collecting system resulted in renal vasoconstriction (∼30% reduction in ERPF, p < 0.05). Dilation of the single-needle access tract to create the nephrostomy did not lead to a further decline in ERPF. PERC surgical procedure-mediated renal vasoconstriction was most evident at the 1-hour posttreatment time point. A reduction in EPAH was only observed in pig kidneys with a nephrostomy. CONCLUSIONS: Needle puncture of the kidney for percutaneous access to the renal collecting system is the major driving force for the renal vasoconstriction observed after PCNL surgery, whereas creation of the nephrostomy appears to be largely responsible for decreasing tubular OAT activity.