Temporal bone studies by systemic arterial perfusion and intralabyrinthine in situ immersion—II. Secretory and reabsorptive areas in the cochlea and crista ampullaris

Micron (1969) ◽  
1980 ◽  
Vol 11 (2) ◽  
pp. 103-114
Author(s):  
Matti Anniko ◽  
Per-G. Lundquist
Keyword(s):  
Temporal Bone ◽  
Arterial Perfusion ◽  
Crista Ampullaris

Tone-dependent responses to endothelin in the isolated perfused fetal sheep pulmonary circulation in situ

1991 ◽  
Vol 70 (3) ◽  
pp. 1228-1234 ◽  
Author(s):  
S. Cassin ◽  
V. Kristova ◽  
T. Davis ◽  
P. Kadowitz ◽  
G. Gause
Keyword(s):  
Pulmonary Circulation ◽  
Vena Cava ◽  
Fetal Lung ◽  
Left Pulmonary Artery ◽  
Pulmonary Vasculature ◽  
Fetal Sheep ◽  
Vascular Responses ◽  
Arterial Perfusion ◽  
Ovine Fetal

Pulmonary vascular responses to endothelin (ET-1), a peptide derived from endothelial cells in culture, were investigated in the ovine fetus delivered by cesarean section from chloralose-anesthetized ewes with intact umbilical circulation. Circulation to the lower left lobe of the fetal lung was isolated in situ and perfused at constant flow with blood withdrawn from the inferior vena cava. Injection of graded doses of ET-1 into the left pulmonary artery decreased pulmonary arterial perfusion pressure in a dose-related manner. At doses of 100, 300, and 1,000 ng, pulmonary vascular resistance per kilogram body weight (PVR/kg) was decreased 30, 40, and 42%, respectively. However, when fetuses were ventilated with 100% oxygen, 100- and 300-ng doses of ET-1 decreased PVR/kg by 5 and 9%, respectively. In contrast, injection of 1,000 ng of ET-1 resulted in a reversal of the response, and PVR/kg was increased by 70%. Ventilation of the right lung alone resulted in a similar reversal of the vasodilator response to 1,000 ng of ET-1, and a 138% increase in PVR/kg was recorded. These studies demonstrate for the first time that ET-1 has vasodilator activity in the normally high-tone ovine fetal pulmonary circulation. In addition, these results show that ET-1 has vasoconstrictor activity in the newly ventilated low-tone pulmonary vasculature. The present data indicate the pulmonary vascular responses to ET-1 are tone dependent in the ovine fetal pulmonary circulation.

pHi and pHo at different depths in perfused myocardium measured by confocal fluorescence microscopy

1998 ◽  
Vol 275 (6) ◽  
pp. H1937-H1947 ◽  
Author(s):  
Barbara J. Muller-Borer ◽  
Hua Yang ◽  
Sayed A. M. Marzouk ◽  
John J. Lemasters ◽  
Wayne E. Cascio
Keyword(s):  
Free Acid ◽  
Fluorescent Microscopy ◽  
Ventricular Myocardium ◽  
Dual Emission ◽  
Arterial Perfusion ◽  
Butanedione Monoxime ◽  
Different Depths ◽  
Endocardial Surface ◽  
Confocal Fluorescent Microscopy

Confocal microscopy and the H+-sensitive fluorophore carboxyseminaphthorhodafluor-1 (SNARF-1) were used to measure either intracellular pH (pHi) or extracellular pH (pHo) in isolated, arterially perfused rabbit papillary muscles. Single-excitation, dual-emission fluorescent images of the endocardial surface and underlying myocardium to a depth of 300 μm were simultaneously recorded from perfused cylindrical muscles suspended in a controlled atmosphere oriented oblique to the focal plane. Contraction was inhibited by the addition of butanedione monoxime. In separate muscles, pHo was measured during continuous perfusion of SNARF-1 free acid. pHi measurements were made after the muscle was loaded with SNARF-1/AM and the extracellular space was cleared of residual fluorophore. Initial experiments demonstrated the uniformity of ratiometric measurements as a function of pH, image depth, and fluorophore concentration, thereby establishing the potential feasibility of this method for quantitative intramural pH measurements. In subsequent experiments, the method was validated in isolated, arterially perfused rabbit papillary muscle during normal arterial perfusion and as pHi and pHo were altered by applying CO2 externally, exchanging HEPES and bicarbonate buffers, and changing pHi with NH4Cl washout. We conclude that in situ confocal fluorescent microscopy can measure pHi and pHo changes at the endocardial surface and deeper endocardial layers in arterially perfused ventricular myocardium. This method has the potential to study pHi regulation in perfused myocardium at boundaries where diffusion of gases, metabolites, and peptides are expected to modify processes that regulate pHi.

Application and In situ calibration of a pulsed-doppler flowmeter for blood flow measurement in crustaceans

1994 ◽  
Vol 74 (2) ◽  
pp. 455-458 ◽  
Author(s):  
C.N. Airriess ◽  
B.R. McMahon ◽  
I.J. McGaw ◽  
G.B. Bourne
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
The Body ◽  
Pulsed Doppler ◽  
Arterial Perfusion ◽  
Non Invasive ◽  
In Situ Calibration ◽  
Flow Through ◽  
Doppler Flowmeter

The pulsed-Doppler flowmeter permits continuous, non-invasive measurement of blood flow through several arteries simultaneously. Summation of volume flow rates through all arteries leaving the heart allows determination of cardiac output, stroke volume, and the percentage of cardiac output delivered to each region of the body. The use of this system for investigating changes in arterial perfusion as well as its calibration in situ are described.

Graded alterations of RBC aggregation influence in vivo blood flow resistance

2004 ◽  
Vol 287 (6) ◽  
pp. H2644-H2650 ◽  
Author(s):  
Ozlem Yalcin ◽  
Murat Uyuklu ◽  
Jonathan K. Armstrong ◽  
Herbert J. Meiselman ◽  
Oguz K. Baskurt
Keyword(s):  
Flow Resistance ◽  
Muscle Tone ◽  
Control Mechanisms ◽  
Vascular Control ◽  
Arterial Perfusion ◽  
Cell Coating ◽  
Rbc Aggregation ◽  
In Vivo Effects

Although the effects of red blood cell (RBC) aggregation on low-shear rate blood viscosity are well known, the effects on in vivo flow resistance are still not fully resolved. The present study was designed to explore the in vivo effects of RBC aggregation on flow resistance using a novel technique to enhance aggregation: cells are covalently coated with a block copolymer (Pluronic F-98) and then suspended in unaltered plasma. RBC aggregation was increased in graded steps by varying the Pluronic concentration during cell coating and was verified by microscopy and erythrocyte sedimentation rate (ESR), which increased by 200% at the highest Pluronic level. RBC suspensions were perfused through an isolated in situ guinea pig hindlimb preparation while the arterial perfusion pressure was held constant at 100 mmHg via a pressure servo-controlled pump. No significant effects of enhanced RBC aggregation were observed when studies were conducted in preparations with intact vascular control mechanisms. However, after inhibition of smooth muscle tone (using 10−4M papaverin), a significant change in flow resistance was observed in a RBC suspension with a 97% increase of ESR. Additional enhancements of RBC aggregation (i.e., 136 and 162% increases of ESR) decreased flow resistance almost to control values. This was followed by another significant increase in flow resistance during perfusion with RBC suspensions with a 200% increase of ESR. This triphasic effect of graded increases of RBC aggregation is most likely explained by an interplay of several hemodynamic mechanisms that are triggered by enhanced RBC aggregation.

scholarly journals Measurement of Free Intracellular and Transfer RNA Amino Acid Specific Activity and Protein Synthesis in Rat Brain in vivo

1990 ◽  
Vol 10 (2) ◽  
pp. 162-169 ◽  
Author(s):  
Katharine M. Hargreaves-Wall ◽  
Jody L. Buciak ◽  
William M. Pardridge
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Specific Activity ◽  
Sprague Dawley ◽  
Arterial Perfusion ◽  
In Situ Perfusion ◽  
Sprague Dawley Rats ◽  
Brain Protein Synthesis

Brain protein synthesis was measured in anesthetized adult, male Sprague–Dawley rats by an in situ internal carotid arterial perfusion technique using [3H]leucine. The specific activity of free intracellular leucine and of tRNA leucine were determined by HPLC separation of phenylisothiocyanate (PITC) derivatives of amino acids. The specific activity of the leucyl-tRNA pool rapidly equilibrated with the free intracellular leucine pool within 2 min. The specific activity of the tRNA and free leucine pools in brain reached equilibrium by 10 min. Plasma amino acid specific activity, however, remained threefold higher than the specific activity of tRNA and free leucine pools. Estimates of protein synthesis were 0.62 ± 0.06 nmol/min/g and were constant between 10 and 30 min of perfusion. The in situ perfusion model for protein synthesis described is a controlled system suited to measurements of protein synthesis in brain that can be applied to the study of brain metabolism under changing physiological conditions.

A rat model for studying the intestinal circulation

1984 ◽  
Vol 246 (1) ◽  
pp. G56-G61 ◽  
Author(s):  
L. Anzueto ◽  
J. N. Benoit ◽  
D. N. Granger
Keyword(s):  
Blood Flow ◽  
Venous Pressure ◽  
Mesenteric Arteries ◽  
Fluid Exchange ◽  
Jugular Veins ◽  
Arterial Perfusion ◽  
Intestinal Microcirculation ◽  
Capillary Fluid ◽  
Oxygen Difference

A preparation is described that allows for whole-organ studies on the rat intestinal microcirculation. The preparation is an in situ autoperfused segment of small intestine. An arterial perfusion circuit is established between the carotid and superior mesenteric arteries and a venous circuit between the superior mesenteric and jugular veins. This model allows for measurements of superior mesenteric arterial and venous pressures, blood flow, arteriovenous oxygen difference, lymph flow, capillary pressure, capillary reflection coefficient, and the capillary filtration coefficient. Preliminary studies using this model indicate a resting blood flow of approximately 120 ml X min-1 X 100 g-1. Resting intestinal oxygen consumption is approximately two to three times the value reported for dogs and cats. Experiments were performed to assess the responses of the preparation to commonly employed physiological perturbations, including pressure-flow autoregulation, functional hyperemia, and response to venous pressure elevations. The observed responses are consistent with intrinsic control of resistance and exchange vessels. The model should prove useful for future studies regarding the physiology and pathology of intestinal hemodynamics, oxygenation, and capillary fluid exchange.

Rendez vous with Saturn's rings

1984 ◽  
Vol 75 ◽  
pp. 743-759 ◽  
Author(s):  
Kerry T. Nock
Keyword(s):  
Solar Energy ◽  
Electric Propulsion ◽  
Power Source ◽  
Propulsion System ◽  
Low Thrust ◽  
Ring Plane ◽  
The Earth ◽  
Total Impulse ◽  
Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

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