A nonocclusive cannula for sampling venous blood from the interscapular brown fat of conscious rats

1986 ◽  
Vol 64 (11) ◽  
pp. 1434-1439 ◽  
Author(s):  
Stephanie W. Y. Ma ◽  
Brita E. NaDeau ◽  
David O. Foster
Keyword(s):  
Blood Flow ◽  
Venous Blood ◽  
Blood Flows ◽  
Brown Adipose ◽  
Microsphere Method ◽  
Diet Induced Thermogenesis ◽  
Conscious Animals ◽  
Special Cannula ◽  
Main Vein

Lack of an adequate method for sampling venous blood from the brown adipose tissue (BAT) of conscious animals has impeded study of the in vivo metabolism of this tissue during physiological activation of its thermogenic function. This paper describes a technique for cannulating the main vein (Sulzer's) of the interscapular BAT (IBAT) of rats in a manner that does not impair blood flow and allows multiple venous sampling over several hours in conscious animals. The technique was tested over the widest possible range of IBAT blood flows by applying it to measurements of IBAT arteriovenous O2 differences in barbital-anesthetized, cold-acclimated rats infused with vehicle or with various doses of noradrenaline. Comparison was made with controls in which samples of IBAT venous blood were obtained by cutting Sulzer's vein. Blood flow was measured by the microsphere method. These tests showed that the presence of the special cannula in Sulzer's vein had no significant effect on the blood flow, arteriovenous O2 difference, or O2 consumption of the IBAT at any level of noradrenaline-induced thermogenesis. The new technique will permit examination of the functioning of BAT in nonshivering thermogenesis and diet-induced thermogenesis under much more physiological conditions than hitherto possible. It should also significantly reduce the number of animals required for such studies.

Regional blood flow in rats after a single low-protein, high-carbohydrate test meal

1984 ◽  
Vol 247 (1) ◽  
pp. R160-R166 ◽  
Author(s):  
Z. Glick ◽  
S. J. Wickler ◽  
J. S. Stern ◽  
B. A. Horwitz
Keyword(s):  
Blood Flow ◽  
Test Meal ◽  
Resting State ◽  
Brown Fat ◽  
Blood Flows ◽  
High Carbohydrate ◽  
Low Protein ◽  
Brown Adipose ◽  
White Fat

It was previously observed that a single low-protein, high-carbohydrate test meal results in increased in vitro thermic activity of brown adipose tissue. In the present study, we have examined whether such a meal increases the in vivo thermic activity, estimated from measurement of the rate of blood flow. With radioactively labeled microspheres, blood flows into brown fat and several other tissues were determined in meal-deprived (n = 11) and meal-fed (n = 11) rats. The microspheres were injected into the heart of anesthetized animals about 2-2.5 h after the test meal, one injection in the resting state and one during maximal norepinephrine stimulation. In the resting state, blood flow per gram tissue more than doubled in the brown fat (P less than 0.05) and was increased more than 50% in the heart (P less than 0.01) of the fed group. Blood flows into liver and retroperitoneal white fat were reduced by 40 (P less than 0.01) and 30%, respectively, in the fed group. During norepinephrine infusion, significant meal-associated increases in blood flow were evident only in brown fat (P less than 0.05) and the soleus muscle (P less than 0.05), whereas a significant decrease was observed in the liver (P less than 0.05). No statistically significant meal-associated changes in norepinephrine-stimulated blood flow were found in the other tissues examined (i.e., heart, gastrocnemius, and diaphragm muscles, kidneys, white fat, spleen, and adrenals). Our in vivo data thus support the view that brown fat plays a role in the thermic effect of a meal.

Influence of a mixed meal on splanchnic and interscapular energy expenditure in humans

1991 ◽  
Vol 260 (2) ◽  
pp. E232-E237 ◽  
Author(s):  
T. Brundin ◽  
J. Wahren
Keyword(s):  
Blood Flow ◽  
Venous Blood ◽  
Venous Blood Flow ◽  
O2 Uptake ◽  
Mixed Meal ◽  
Interscapular Brown Adipose Tissue ◽  
Blood Flows ◽  
Blood Temperature ◽  
Brown Adipose ◽  
Regional Blood Flows

Pulmonary, splanchnic, and interscapular O2 uptake was studied in 14 male volunteers before and for 90 min after a mixed meal. Thermistor catheters were inserted into a hepatic vein, the azygous vein, the pulmonary artery, and the aorta. Systemic and regional blood flows were determined during indirect calorimetry measurements and recordings of blood temperature. After the meal, pulmonary O2 uptake rose by 33-49 ml/min and splanchnic O2 uptake increased by 16-25 ml/min. In the azygous region O2 uptake did not increase significantly. Cardiac output increased after the meal by 1.1-1.5 l/min and splanchnic blood flow rose by 0.4-0.9 l/min. Azygous venous blood flow increased from 130 +/- 19 ml/min to 163 +/- 23 ml/min. In relation to splanchnic O2 uptake, the blood-drained splanchnic heat was low, 11 +/- 1 J/ml, and decreased to 7 +/- 1 J/ml after the meal. We conclude that after a mixed meal approximately one-half of the rise in O2 uptake occurs in the splanchnic organs; azygous-drained tissues, including possible interscapular brown adipose tissue, contribute minimally. The amount of heat drained with blood from the splanchnic region was low in relation to the splanchnic O2 uptake, indicating that splanchnic heat may be dissipated by routes other than the perfusing blood.

Blood flow in normal and dystrophic hamsters during nonshivering thermogenesis

1984 ◽  
Vol 247 (1) ◽  
pp. R189-R195 ◽  
Author(s):  
S. J. Wickler ◽  
B. A. Horwitz
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Cardiac Muscle ◽  
Brown Fat ◽  
Tissue Blood Flow ◽  
Potential Contribution ◽  
Nonshivering Thermogenesis ◽  
Blood Flows ◽  
Brown Adipose

The genetically dystrophic line of hamsters (BIO 14.6) has a significantly reduced capacity for nonshivering thermogenesis (NST) when compared with age-matched normal animals. Of those tissues contributing most to NST, three are altered in the dystrophic hamster (brown fat and cardiac and skeletal muscle). This study has used regional blood flows in response to isoproterenol (a potent stimulator of NST) as a measure of the potential contribution of these tissues to NST. Both isoproterenol-induced O2 consumption and cardiac output were lower in the dystrophic hamsters (13.0 +/- 0.4 vs. 18.2 +/- 0.68 ml O2 X g-0.67 X h-1 and 2.10 +/- 0.10 vs 2.98 +/- 0.16 ml X g-0.67 X min-1, respectively). Tissue blood flow was measured to brown fat, heart, skeletal muscle, liver, kidneys, adrenals, skin, and white fat. Isoproterenol was found to increase blood flows to brown fat, skeletal muscle, and cardiac muscle in normal animals and to brown fat and skeletal muscle in dystrophic hamsters, suggesting that these tissues contribute to NST. However, when corrected for body weight differences, blood flows during isoproterenol infusion to skeletal muscle and to cardiac muscle did not significantly differ between normal and dystrophic animals (2.71 +/- 0.29 vs. 3.33 +/- 0.42 and 2.81 +/- 0.25 vs. 1.85 +/- 0.24 ml X 100 g body wt-1, respectively). In contrast, normal brown adipose tissue had significantly elevated blood flows (3.50 +/- 0.39 vs. 2.28 +/- 0.27 ml X 100 g body wt-1). Thus these observations provide in vivo support for the conclusion that the reduced NST capacity of dystrophic hamsters is due, in large part, to a reduced thermogenic contribution of brown fat.

Blood flow to brown fat in lean and obese adrenalectomized Zucker rats

1986 ◽  
Vol 251 (5) ◽  
pp. R851-R858
Author(s):  
S. J. Wickler ◽  
B. A. Horwitz ◽  
J. S. Stern
Keyword(s):  
Blood Flow ◽  
Weight Gain ◽  
Brown Fat ◽  
Zucker Rats ◽  
Zucker Rat ◽  
Nonshivering Thermogenesis ◽  
Brown Adipose ◽  
Obese Rats

The Zucker obese rat is characterized by decreased capacity for diet-induced and for nonshivering thermogenesis. This decrease is due, in large part, to reduced thermogenesis in depots of brown adipose tissue, a major source of heat production in rats. Adrenalectomy retards the weight gain observed in the obese rats and also normalizes brown fat guanosine 5'-diphosphate (GDP) binding, an in vitro measure of brown fat thermogenic capacity. This study examined the effect of adrenalectomy on brown fat blood flow, an in vivo measure of the tissue's function, and on norepinephrine-induced O2 consumption (NST) of 11-wk-old obese (fa/fa) and lean (Fa/?) rats. Adrenalectomy had little effect on weight gain, NST, or norepinephrine-stimulated blood flow to brown fat in lean rats. However, adrenalectomy produced profound changes in the obese animals, preventing the weight gain normally occurring in the obese rats and normalizing both NST capacity and norepinephrine-stimulated blood flow to brown fat. These findings provide further support for the importance of brown fat thermogenesis and glucocorticoids in modulating the obesity of the Zucker rat.

scholarly journals Testicular microvascular flow is altered in Klinefelter syndrome and predicts circulating testosterone

2021 ◽  
Author(s):  
Francesco Carlomagno ◽  
Carlotta Pozza ◽  
Marta Tenuta ◽  
Riccardo Pofi ◽  
Luigi Tarani ◽  
...  
Keyword(s):  
Blood Flow ◽  
Klinefelter Syndrome ◽  
Mean Transit Time ◽  
Venous Blood ◽  
Experimental Studies ◽  
Principal Component ◽  
Endocrine Function ◽  
Venous Blood Flow ◽  
Testicular Blood Flow

ABSTRACTContextExperimental studies on Klinefelter syndrome (KS) reported increased intratesticular testosterone (T) levels coexisting with reduced circulating levels. Abnormalities in testicular microcirculation have been claimed; however, no studies investigated in vivo testicular blood flow dynamics in humans with KS.ObjectiveTo analyze the testicular microcirculation in KS by contrast-enhanced ultrasonography (CEUS) and correlate vascular parameters with endocrine function.Design and SettingProspective study. University Settings.Patients51 testicular scans, 17 testes from 10 T-naïve subjects with KS and 34 testes from age-matched eugonadal men (CNT) who underwent CEUS for incidental nonpalpable testicular lesions.Main OutcomesCEUS kinetic parameters.ResultsCEUS revealed slower testicular perfusion kinetics in subjects with KS than in age-matched CNT. Specifically, the wash-in time (Tin, p = 0.008), mean transit time (MTT, p = 0.008), time to peak (TTP, p < 0.001), and washout time (Tout 50%, p = 0.008) were all prolonged. Faster testicular blood flow was associated with higher total T levels. Principal component analysis and multiple linear regression analyses confirmed the findings, and supported a role for reduced venous blood flow as independent predictor of total T levels.ConclusionsTesticular venous blood flow is altered in KS and independently predicts T peripheral release.

Hemodynamics and metabolism of the in vivo vascularly isolated canine pancreas.

1979 ◽  
Vol 236 (6) ◽  
pp. E626
Author(s):  
R J Alteveer ◽  
M J Jaffe ◽  
J Van Dam
Keyword(s):  
Blood Flow ◽  
Glucose Uptake ◽  
Venous Blood ◽  
Fatty Acid Uptake ◽  
Acid Uptake ◽  
Anesthetized Dogs ◽  
Metabolic Variables ◽  
The Stability ◽  
First Time

Surgical procedures are detailed that have yielded for the first time an in vivo vascularly isolated, autoperfused preparation of the entire pancreas in anesthetized dogs. Previous studies had isolated only part of the pancreas or had resorted to blood-flow techniques not requiring pooled pancreatic venous blood, necessary for metabolic studies of the organ. Pancreatic blood flow (48 ml/min), O2 uptake (180 mumol/min), glucose uptake (51.0 mumol/min), lactate output (6.6 mumol/min), net free fatty acid uptake (2.23 mumol/min), all per 100 g tissue, and various other measured and calculated hemodynamic and metabolic variables were determined on the preparation during control conditions. The stability of the preparation was verified by serial determinations of these parameters and of blood alpha-amylase and beta-glucuronidase levels from 1 to 2.5 h postsurgery. Metabolic rate and glucose uptake were both found to be much higher than in intestinal tissues and approached values characteristic of liver tissue.

Vasodilation or altered perfusion pressure moves 15-micrometers spheres trapped in the gut wall

1982 ◽  
Vol 243 (1) ◽  
pp. H123-H127
Author(s):  
L. C. Maxwell ◽  
A. P. Shepherd ◽  
G. L. Riedel
Keyword(s):  
Blood Flow ◽  
Perfusion Pressure ◽  
Venous Blood ◽  
Intestinal Blood Flow ◽  
Experimental Conditions ◽  
Tissue Samples ◽  
Intestinal Segments ◽  
Microsphere Method ◽  
Adjacent Segments ◽  
Isoproterenol Infusion

To determine whether the microsphere method for measuring the intramural distribution of intestinal blood flow is affected by perfusion pressure or vasodilation, we infused radioactive 9- and 15-micrometers spheres into adjacent segments of isolated canine small bowel. After sphere infusion the blood supply of the control loop was occluded, and the vasculature of the experimental loop was either dilated by infusing isoproterenol or was subjected to increased perfusion pressure. Intestinal segments were dissected into mucosal, submucosal, and muscularis samples. Venous blood was collected during sphere infusions and experimental perturbations. Accumulations of spheres in tissue samples and venous blood were assessed in a gamma radioactivity counter. Isoproterenol caused previously infused spheres to leave submucosa and redistributed them primarily to mucosa with few additional spheres reaching venous blood. An increase in perfusion pressure also dislodged spheres from submucosa, but these did reach venous blood. The combined estimate of mucosal plus submucosal blood flow was relatively unaffected by isoproterenol infusion but was significantly altered by increased perfusion pressure. These results have the following implications for microsphere studies of the intramural distribution of intestinal blood flow: 1) tissue must be sampled after each sphere infusion unless the possibility of sphere migration has been experimentally eliminated and 2) even a two-compartment fractionation of blood flow into muscularis and mucosal-plus-submucosal compartments is not valid under some experimental conditions.

Hemodynamic effects of leukotriene C4 in ovine fetus

1990 ◽  
Vol 259 (6) ◽  
pp. E851-E855
Author(s):  
B. A. Meyer ◽  
S. W. Walsh ◽  
V. M. Parisi
Keyword(s):  
Blood Flow ◽  
Vena Cava ◽  
Cardiovascular Effects ◽  
In Vivo Studies ◽  
Leukotriene C4 ◽  
Blood Flows ◽  
Before And After ◽  
Placental Blood ◽  
Near Term

Leukotrienes are synthesized during pregnancy and produce cardiovascular effects in adults. We hypothesized that leukotriene C4 would cause vasoconstriction in the fetus and placenta. Eight near-term, unanesthetized ovine fetuses were studied before and after infusion of 10 micrograms leukotriene C4 (LTC4) into the fetal vena cava. Cardiovascular monitoring of maternal and fetal arterial pressures and heart rates was performed. Fetal blood flows were measured by the radioactive-microsphere technique. Sustained elevations in systolic and diastolic blood pressure and decreased fetal heart rate began by 1 min and returned to baseline by 30 min. Arterial pH fell from 7.33 +/- 0.01 to 7.29 +/- 0.01 at 15 min (P less than 0.05) and to 7.29 +/- 0.01 at 30 min (P less than 0.05), with a significant increase in base deficit from 0.7 +/- 0.7 to 3.5 +/- 0.7 at 15 min (P less than 0.05) and to 2.9 +/- 1.0 at 30 min (P less than 0.05). Fetal PO2 and PCO2 were unchanged. Significant decreases in blood flow and resistance were seen in the umbilical placental circulation as well as in fetal skeletal muscle and intestine. Blood flow and resistance were unchanged in the renal and adrenal vascular beds. Fetal administration of LTC4 caused no changes in maternal cardiovascular parameters. These findings represent the first in vivo studies of the effects of a lipoxygenase metabolite on fetal-placental blood flow.

Segment stroke work and metabolism depend on coronary blood flow in the pig

1978 ◽  
Vol 234 (5) ◽  
pp. H597-H607 ◽  
Author(s):  
D. F. Stowe ◽  
D. G. Mathey ◽  
W. Y. Moores ◽  
S. A. Glantz ◽  
R. M. Townsend ◽  
...  
Keyword(s):  
Blood Flow ◽  
Carotid Artery ◽  
Myocardial Ischemia ◽  
Mechanical Performance ◽  
Venous Blood ◽  
Lactate Production ◽  
Blood Gases ◽  
Metabolic Effects ◽  
Stroke Work ◽  
Blood Flows

We determined the mechanical and metabolic effects of graded myocardial ischemia in 23 open-chest, anesthetized pigs. By connecting the midportion of the left anterior descending artery (LAD) to the carotid artery via a constant volume, calibrated pump, we reduced the flow in the LAD to 0, 25, 50, and 75% of control rates for periods of 1 h. Flows of 100% and 150% were also examined. Using pairs of ultrasonic crystals to measure segment dimensions, we calculated segment shortening and thickening, and total and systolic stroke work in the ischemic and normally perfused segments. Blood gases, pH, and lactate and inosine balances were determined from the regional coronary venous blood. At coronary blood flows of 0, 25, 50, and 75% of normal resting flow, total segment work was 8 +/- 8, 25 +/- 4, 51 +/- 5, and 80 +/- 6% of control, respectively, while systolic segment work was -2 +/- 5, -10 +/- 5, 40 +/- 5, and 86 +/- 7% of control, respectively (means +/- SE). Thus, the decrease in total segment stroke work is proportional to the decrease in flow over the range 0-100%. However, no useful work (i.e., systolic work) is done until flow exceeds 25%. Segment shortening and thickening are significantly depressed with flows diminished by only 25%. Segmental inosine production correlates with lactate production and parallels decreased mechanical performance.

Measurements of Hemodialysis Catheter Blood Flow in Vivo

2002 ◽  
Vol 25 (4) ◽  
pp. 276-280 ◽  
Author(s):  
Z. J. Twardowski ◽  
J. D. Haynie
Keyword(s):  
Blood Flow ◽  
Average Length ◽  
Internal Diameter ◽  
Hemodialysis Catheter ◽  
Blood Flows ◽  
Catheter Design ◽  
Poiseuille’S Equation ◽  
Different Diameters ◽  
The Relationship

The relationship between the blood flow and inflow and outflow pressures was determined in PermCath, dual lumen catheters during regular hemodialyses in vivo in eight patients with average hematocrit of 38%. From the luer lock connector the catheters had an average length of 32 cm to the outflow tip and 30 cm to the inflow tip. The catheters had an internal diameter of 0.2 cm and were straight before implantation. Dialyses were performed on Fresenius 2008 D or E machines with ReadySet™ blood lines with an 8 mm ID pump segment and a noncollapsible arterial chamber. Pressures and blood flows were measured at pump speeds from 50 to 500 ml/min in increments of 50 ml/min with lines in normal configuration. Blood flow was measured continuously using ultrasound. The correlations between pressures and flows are not linear. The best correlations are according to the Stirling model of exponential growth category equation. Inflow pressure = -9.07–0.4865*(exp(0.0020*blood flow)-1)/0.0020 Outflow pressure = -28.14+0.5002*(exp(0.0015*blood flow)-1/0.0015 Based on these results and Poiseuille's equation a table was developed for the optimal relationship between catheter length and diameter to achieve standardized (average, low and high) blood flows regardless of the lengths of the catheters. The diameter/length relationships are based on theoretical considerations. Because resistances depend on the material and shape of the tubing, the actual measurements of flow/pressure relationships should be done once tubings of different diameters are manufactured, and final catheter design has to be based on these measurements.

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