Measurement of interstitial muscle glucose and lactate concentrations during an oral glucose tolerance test

1996 ◽  
Vol 271 (6) ◽  
pp. E1003-E1007 ◽  
Author(s):  
M. Muller ◽  
A. Holmang ◽  
O. K. Andersson ◽  
H. G. Eichler ◽  
P. Lonnroth
Keyword(s):  
Blood Flow ◽  
Glucose Uptake ◽  
Flow Rate ◽  
Glucose Concentration ◽  
Interstitial Fluid ◽  
Human Subjects ◽  
Muscle Blood Flow ◽  
Blood Flow Rate ◽  
Capillary Wall ◽  
Oral Glucose

To study the relationship between blood flow rate and muscle metabolism, muscle microdialysis was performed in nine human subjects (5 females and 4 males) after an oral glucose load (75 g). Two microdialysis probes were inserted into the medial femoral muscle for estimation of glucose and lactate concentrations in the interstitial fluid, and the muscle blood flow was measured concomitantly with strain-gauge plethysmography. After subjects fasted overnight, their glucose concentration in arterial plasma and interstitial fluid was 4.6 +/- 0.13 vs. 3.8 +/- 0.23 mmol/l (P < 0.05), and the corresponding lactate concentrations were 0.60 +/- 0.07 vs. 0.83 +/- 0.07 mmol/l (P < 0.05). Muscle blood flow was 5.2 +/- 0.7 and 7.5 +/- 1.4 ml.100 g-1.min-1 (P < 0.05) at 0 and 90 min after oral glucose, respectively. The arterial-interstitial concentration differences of glucose increased after oral glucose [at 0 min 0.73 +/- 0.24 vs. 2.19 +/- 0.60 mmol/l at 90 min (P < 0.001)]. The corresponding values for lactate were -0.23 +/- 0.10 at 0 min vs.-0.26 +/- 0.18 mmol/l at 90 min (not significant). The data show that 1) the capillary wall is partly rate limiting for glucose uptake, and 2) after oral glucose, the glucose concentration gradient over the capillary wall increases despite a limited increase in blood flow rate, which then mediates approximately 10-20% of total enhancement of glucose uptake in muscle.

scholarly journals Effect of Wall Compliance and Permeability on Blood-Flow Rate in Counter-Current Microvessels Formed From Anastomosis During Tumor-Induced Angiogenesis

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Peng Guo ◽  
Bingmei M. Fu
Keyword(s):  
Blood Flow ◽  
Flow Rate ◽  
Vessel Wall ◽  
Interstitial Fluid ◽  
Tumor Tissue ◽  
Blood Flow Rate ◽  
Tumor Vasculature ◽  
Negligible Effect ◽  
Wall Compliance ◽  
Counter Current

Tumor blood-flow is inhomogeneous because of heterogeneity in tumor vasculature, vessel-wall leakiness, and compliance. Experimental studies have shown that normalization of tumor vasculature by antiangiogenic therapy can improve tumor microcirculation and enhance the delivery of therapeutic agents to tumors. To elucidate the quantitative relationship between the vessel-wall compliance and permeability and the blood-flow rate in the microvessels of the tumor tissue, the tumor tissue with the normalized vasculature, and the normal tissue, we developed a transport model to simultaneously predict the interstitial fluid pressure (IFP), interstitial fluid velocity (IFV) and the blood-flow rate in a counter-current microvessel loop, which occurs from anastomosis in tumor-induced angiogenesis during tumor growth. Our model predicts that although the vessel-wall leakiness greatly affects the IFP and IFV, it has a negligible effect on the intravascular driving force (pressure gradient) for both rigid and compliant vessels, and thus a negligible effect on the blood-flow rate if the vessel wall is rigid. In contrast, the wall compliance contributes moderately to the IFP and IFV, but significantly to the vessel radius and to the blood-flow rate. However, the combined effects of vessel leakiness and compliance can increase IFP, which leads to a partial collapse in the blood vessels and an increase in the flow resistance. Furthermore, our model predictions speculate a new approach for enhancing drug delivery to tumor by modulating the vessel-wall compliance in addition to reducing the vessel-wall leakiness and normalizing the vessel density.

Nocturnal variations in subcutaneous blood flow rate in lower leg of normal human subjects

1991 ◽  
Vol 260 (2) ◽  
pp. H480-H485 ◽  
Author(s):  
J. H. Sindrup ◽  
J. Kastrup ◽  
B. Jorgensen ◽  
J. Bulow ◽  
N. A. Lassen
Keyword(s):  
Blood Flow ◽  
Flow Rate ◽  
Human Subjects ◽  
Blood Flow Rate ◽  
Lower Leg ◽  
Tissue Blood Flow ◽  
Subcutaneous Blood Flow ◽  
Normal Human ◽  
Night Period ◽  
133Xe Washout

Subcutaneous adipose tissue blood flow rate was measured in the lower leg of 22 normal human subjects over 12- to 20-h ambulatory conditions. The 133Xe washout technique, portable CdTe(Cl) detectors, and a portable data storage unit were used. The tracer depot was applied on the medial aspect of the right lower leg 10 cm proximal to the malleolar level by means of the epicutaneous, atraumatic labeling technique. The change from upright to supine position from day 1 in the beginning of the night period elicited an instantaneous blood flow rate increment of 30-40% in accordance with a decrease in central and local postural sympathetic vasoconstrictor activity. During sleep, characteristic variations in subcutaneous blood flow were disclosed. The 133Xe washout curve could be divided into three segments with significantly different slopes. Approximately 90 min after the subject went to sleep, an additional blood flow rate increment of considerable magnitude was observed. The mean increase was 84%, but in several cases a greater than 200% increment was measured (maximum 244%). The intra-individual coefficient of variation for the nocturnal blood flow response was in triplicate measurements 25% (n = 9). The hyperemic phase lasted approximately 100 min after which the blood flow rate returned to the level measured at the beginning of the night period. The blood flow rates measured on the second day did not differ from those on the first day. Control measurements performed under similar thermal conditions, but with the subjects kept awake, did not reveal any hyperemic phases. This points toward changes in cardiovascular regulatory mechanisms during sleep.(ABSTRACT TRUNCATED AT 250 WORDS)

Neural control of glucose uptake by skeletal muscle after central administration of NMDA

1995 ◽  
Vol 268 (2) ◽  
pp. R492-R497 ◽  
Author(s):  
C. H. Lang ◽  
M. Ajmal ◽  
A. G. Baillie
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Glucose Uptake ◽  
Neural Control ◽  
Plasma Insulin ◽  
Regional Blood Flow ◽  
Muscle Blood Flow ◽  
Whole Body ◽  
Glucose Disposal ◽  
Central Administration

Intracerebroventricular injection of N-methyl-D-aspartate (NMDA) produces hyperglycemia and increases whole body glucose uptake. The purpose of the present study was to determine in rats which tissues are responsible for the elevated rate of glucose disposal. NMDA was injected intracerebroventricularly, and the glucose metabolic rate (Rg) was determined for individual tissues 20-60 min later using 2-deoxy-D-[U-14C]glucose. NMDA decreased Rg in skin, ileum, lung, and liver (30-35%) compared with time-matched control animals. In contrast, Rg in skeletal muscle and heart was increased 150-160%. This increased Rg was not due to an elevation in plasma insulin concentrations. In subsequent studies, the sciatic nerve in one leg was cut 4 h before injection of NMDA. NMDA increased Rg in the gastrocnemius (149%) and soleus (220%) in the innervated leg. However, Rg was not increased after NMDA in contralateral muscles from the denervated limb. Data from a third series of experiments indicated that the NMDA-induced increase in Rg by innervated muscle and its abolition in the denervated muscle were not due to changes in muscle blood flow. The results of the present study indicate that 1) central administration of NMDA increases whole body glucose uptake by preferentially stimulating glucose uptake by skeletal muscle, and 2) the enhanced glucose uptake by muscle is neurally mediated and independent of changes in either the plasma insulin concentration or regional blood flow.

The Effect of Furosemide on the Intrarenal Blood Flow Distribution in the Dog

1972 ◽  
Vol 50 (8) ◽  
pp. 774-783 ◽  
Author(s):  
Serge Carrière ◽  
Michel Desrosiers ◽  
Jacques Friborg ◽  
Michèle Gagnan Brunette
Keyword(s):  
Blood Flow ◽  
Flow Rate ◽  
Urine Volume ◽  
Flow Distribution ◽  
Blood Flow Rate ◽  
Initial Distribution ◽  
Blood Flow Distribution ◽  
Intrarenal Blood Flow ◽  
Femoral Blood ◽  
Furosemide Administration

Furosemide (40 μg/min) was perfused directly into the renal artery of dogs in whom the femoral blood pressure was reduced (80 mm Hg) by aortic clamping above the renal arteries. This maneuver, which does not influence the intrarenal blood flow distribution, produced significant decreases of the urine volume, natriuresis, Ccreat, and CPAH, and prevented the marked diuresis normally produced by furosemide. Therefore the chances that systemic physiological changes occurred, secondary to large fluid movements, were minimized. In those conditions, however, furosemide produced a significant increase of the urine output and sodium excretion in the experimental kidney whereas Ccreat and CPAH were not affected. The outer cortical blood flow rate (ml/100 g-min) was modified neither by aortic constriction (562 ± 68 versus 569 ± 83) nor by the subsequent administration of furosemide (424 ± 70). The blood flow rate of the outer medulla in these three conditions remained unchanged (147 ± 52 versus 171 ± 44 versus 159 ± 54). The initial distribution of the radioactivity in each compartment remained comparable in the three conditions. In parallel with the results from the krypton-85 disappearance curves, the autoradiograms, silicone rubber casts, and EPAH did not suggest any change in the renal blood flow distribution secondary to furosemide administration.

The Effect of Hematocrit on the Clearance of Small Molecules during Hemodialysis

1983 ◽  
Vol 6 (3) ◽  
pp. 127-130 ◽  
Author(s):  
C. Woffindin ◽  
N.A. Hoenich ◽  
D.N.S. Kerr
Keyword(s):  
Blood Flow ◽  
Regression Analysis ◽  
Small Molecules ◽  
Flat Plate ◽  
Flow Rate ◽  
Distribution Curve ◽  
Blood Flow Rate ◽  
Hollow Fibre ◽  
Urea Clearance ◽  
Flow Rates

Data collected during the evaluation of a series of hemodialysers were analysed to see the effect of hematocrit on the clearance of urea and creatinine. All evaluations were performed on patients with a range of hematocrits with a mean close to 20%. The urea clearance of those in the upper half of the distribution curve (mean hematocrit 29.4%) was not significantly different from that of patients in the lower half of the distribution curve (mean hematocrit 16.9%) whether the clearance was studied at high or low blood flow rates and with hollow fibre or flat plate disposable hemodialysers. Likewise, there was no correlation between hematocrit and urea clearance by regression analysis. In contrast, the clearance of creatinine was affected by hematocrit being greater at lower hematocrit values. This difference was independent of blood flow rate and dialyser type and was confirmed by regression analysis.

Anoxia and adenosine induce increased cerebral blood flow rate in crucian carp

1994 ◽  
Vol 267 (2) ◽  
pp. R590-R595 ◽  
Author(s):  
G. E. Nilsson ◽  
P. Hylland ◽  
C. O. Lofman
Keyword(s):  
Blood Flow ◽  
Flow Rate ◽  
Crucian Carp ◽  
Blood Flow Rate ◽  
Fold Increase ◽  
Liver Glycogen ◽  
Glycolytic Flux ◽  
Brain Blood Flow ◽  
Atp Production ◽  
The Brain

The crucian carp (Carassius carassius) has the rare ability to survive prolonged anoxia, indicating an extraordinary capacity for glycolytic ATP production, especially in a highly energy-consuming organ like the brain. For the brain to be able to increase its glycolytic flux during anoxia and profit from the large liver glycogen store, an increased glucose delivery from the blood would be expected. Nevertheless, the effect of anoxia on brain blood flow in crucian carp has never been studied previously. We have used epireflection microscopy to directly observe and measure blood flow rate on the brain surface (optic lobes) during normoxia and anoxia in crucian carp. We have also examined the possibility that adenosine participates in the regulation of brain blood flow rate in crucian carp. The results showed a 2.16-fold increase in brain blood flow rate during anoxia. A similar increase was seen after topical application of adenosine during normoxia, while adenosine was without effect during anoxia. Moreover, superfusing the brain with the adenosine receptor blocker aminophylline inhibited the effect of anoxia on brain blood flow rate, clearly suggesting a mediatory role of adenosine in the anoxia-induced increase in brain blood flow rate.

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