Publications (21) View all
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Article: Using light spectrum to probe mechanisms for circadian phototransduction in mouse
01/2004; -
Article: Light and Circadian Photobiology: Interactions and Implications for Biotechnology
01/2003; -
Article: The effect of acoustically-induced cavitation on the permeance of a bullfrog urinary bladder.
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ABSTRACT: It is well known that ultrasound enhances drug delivery to tissues, although there is not a general consensus about the responsible mechanisms. However, it is known that the most important factor associated with ultrasonically-enhanced drug permeance through tissues is cavitation. Here we report results from research conducted using a experimental approach adapted from single bubble sonoluminescence experiments which generates very well defined acoustic fields and allows controlled activation and location of cavitation. The experimental design requires that a biological tissue be immersed inside a highly degassed liquid media to avoid random bubble nucleation. Therefore, live frog bladders were used as the living tissue due to their high resistance to hypoxia. Tissue membrane permeance was measured using radiolabeled urea. The results show that an increase in tissue permeance only occurs when cavitation is present near the tissue membrane. Moreover, confocal microscopy shows a direct correlation between permeance increases and physical damage to the tissue.The Journal of the Acoustical Society of America 11/2010; 128(5):2726-38. · 1.55 Impact Factor -
Article: Empty bladder and dehydrated pelvic patch water uptake in Bufo marinus: inhibition by captopril.
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ABSTRACT: Dehydration (10.3 +/- 2.2%, N = 7) caused a significant increase in pelvic patch water uptake (Jv) from 875 +/- 86 (N = 21) to 2130 +/- 150 (N = 21) cm3.cm-2 x 10(-7), while the pectoral Jv increased from 258 +/- 31 (N = 21) to 545 +/- 75 (N = 21 cm3.cm-2 x 10(-7). Captopril inhibited the pelvic patch Jv in empty bladder toads decreasing the Jv from 978 +/- 45 (N = 27) to 607 +/- 38 (N = 27) cm3.cm-2 x 10(-7). In dehydrated toads (15 +/- 2%, N = 14), captopril reduced the pelvic patch Jv from 1807 +/- 213 (N = 21) to 957 +/- 91 (N = 21) cm3.cm-2 x 10(-7). Captopril injection decreased the blood pressure in dehydrated toads from 25.6 +/- 1.9 (N = 21) to 16.9 +/- 1.5 (N = 21) mmHg with no change in heart rate.Comparative biochemistry and physiology. Part A, Physiology 06/1995; 111(1):47-50. -
Article: Regulation of pelvic patch water flow in Bufo marinus: role of bladder volume and ANG II.
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ABSTRACT: This report examines the importance of bladder volume in regulating cutaneous water uptake (Jv, cm3.cm-2.s-1 x 10(-7)) across the ventral pelvic patch and examines the role of angiotensin II (ANG II) and circulation as the regulatory mechanism. Jv in empty-bladder Bufo marinus (bladder volume 3.89 +/- 1.49%, n = 7) was 1,671 +/- 68 (n = 7). Injection of Ringer solution into the bladder (12.8 +/- 2.2%, n = 7) decreased Jv to 1,025 +/- 202 (n = 7). ANG II injected into toads with filled bladders increased Jv in a dose-dependent manner. At 5 micrograms/100 g toad Jv increased by 136 +/- 63 (n = 6), at 50 micrograms/100 g toad by 432 +/- 82 (n = 7), and at 200 micrograms/100 g toad by 620 +/- 142 (n = 5). Saralasin (200 micrograms/100 g toad) completely inhibited the response to ANG II (50 micrograms/100 g toad) and at 1 mg/100 g toad decreased Jv in empty-bladder toads. These experiments indicate that 1) bladder volume participates in the regulation of Jv in the ventral pelvic patch; 2) ANG II increases the Jv in toads with full bladders; 3) saralasin inhibits the high Jv in empty bladder toads; 4) the high Jv, associated with an empty bladder, requires an intact circulation to be maintained; 5) without an intact circulation, the high water flow associated with an empty bladder causes the Na+ content of the tissue in the ventral patch to be reduced; and 6) ANG II causes only a minimal increases in water permeability in the isolated pelvic patch skin.The American journal of physiology 07/1993; 264(6 Pt 2):R1260-5.
