scholarly journals Exchange of potassium and strontium in adult bone

1982 ◽  
Vol 242 (4) ◽  
pp. H705-H712 ◽  
Author(s):  
B. Maltby ◽  
G. J. Lemon ◽  
J. B. Bassingthwaighte ◽  
P. J. Kelly
Keyword(s):  
Cortical Bone ◽  
Time Course ◽  
Volume Of Distribution ◽  
Indicator Dilution ◽  
Adsorption Sites ◽  
Nutrient Artery ◽  
Extravascular Volume ◽  
Kinetics Of ◽  
Adult Bone ◽  
Dilution Curves

The kinetics of exchange of strontium (85Sr) and potassium (42K) were studied in the mid-tibial cortical bone of 37 adult dogs. After injection of these two tracer cations and tracer-labeled albumin into the tibial nutrient artery, two types of observations were made: 1) collection of sequential venous samples to provide the outflow indicator-dilution curves and to calculate the extraction and retention at early times; and 2) detection of energy-selected gamma emissions via a detector over the tibia to give the time course of content of 42K and 85Sr in the tibia. Extractions of K+ and Sr2+ were 50 and 60% during a single transcapillary passage. More Sr2+ than K+ was retained in the first minutes. Their rates of washout over a 3-h period were similar. The interpretation is that the rate of uptake at extravascular sites is faster for Sr2+ than for K+, as is the rate of release, and that the extravascular volume of distribution for Sr2+ (adsorption sites in the interstitium or on bone) is much larger than that for K+ (intracellular).

Physiological parameters of indicator dilution curves

1977 ◽  
Vol 233 (3) ◽  
pp. H350-H355
Author(s):  
L. D. Homer ◽  
A. Small
Keyword(s):  
Cardiac Output ◽  
Satisfactory Agreement ◽  
Single Injection ◽  
Time Lag ◽  
Volume Of Distribution ◽  
Physiological Parameters ◽  
Indicator Dilution ◽  
Diethylenetriaminepentaacetic Acid ◽  
Alternative Techniques ◽  
Dilution Curves

A model incorporating the effects of recirculation time lag, cardiac output, clearance, volume of distribution, and the variance of the distribution of recirculation times is applied to the analysis of indicator dilution curves. Experiments on dogs with use of radioactively labeled diethylenetriaminepentaacetic acid were done to evaluate the model. This five-parameter model can be fitted to data obtained during the period from less than 1 min to 3 h after a single injection of indicator. Estimates of cardiac output and clearance are in satisfactory agreement with estimates obtained by alternative techniques. Estimates of the time lag and volume of distribution are of physiologically plausible magnitude. The variance of the distribution of recirculation times is a new parameter, of which the possible usefulness to physiologists is discussed.

Endothelial extraction of tracer water varies with extravascular water in dog lungs

1987 ◽  
Vol 252 (2) ◽  
pp. H340-H348 ◽  
Author(s):  
F. P. Chinard ◽  
W. O. Cua
Keyword(s):  
Volume Of Distribution ◽  
Indicator Dilution ◽  
Lung Water ◽  
Limited Distribution ◽  
Multiple Indicator Dilution ◽  
Multiple Indicator ◽  
The Time Domain ◽  
Area Product ◽  
Extravascular Volume

In multiple indicator-dilution experiments, transvascular passage of a permeating indicator is conventionally derived from the up-slope separation of the curve of the permeating indicator from that of a vascular reference and is expressed as the extraction (Ec). Extraction may be limited by the barrier (barrier-limited distribution). It may be limited by the volume of distribution accessible to it; in the time domain of an indicator-dilution experiment, the passage to and distribution in the extravascular volume are rapid relative to the velocity of blood in the exchange vessels. We examine here the relations of the extraction of tracer water as tritium oxide (THO) [Ec(THO)] and of the extraction of tracer sodium as 22Na [Ec(22Na)] to extravascular lung water, delta V wev, by adding isotonic fluid to the gas phase of the lungs. The net convective transvascular passage of water is negligible relative to the transendothelial molecular exchange. In 10 experiments in vivo and in 10 experiments in isolated perfused lungs, Ec(THO) increases as delta V wev increases. Ec(22Na) and the permeability-surface area product (PS) for 22Na do not change as delta V wev increases. We conclude that the extraction of THO is determined mainly by the volume accessible to it (flow- or volume-limited distribution) and that the extraction of 22Na is determined mainly by the resistance of the endothelium (barrier-limited distribution). A diffusion limitation in the added alveolar fluid rather than a barrier limitation at the endothelium may moderate Ec(THO).

Effect of atelectasis and embolization on extravascular thermal volume of the lung

1982 ◽  
Vol 53 (6) ◽  
pp. 1614-1619 ◽  
Author(s):  
R. C. Beckett ◽  
B. A. Gray
Keyword(s):  
Pulmonary Circulation ◽  
Weight Ratio ◽  
Dry Weight ◽  
Volume Of Distribution ◽  
Bronchial Obstruction ◽  
Lung Water ◽  
Pulmonary Blood Volume ◽  
Lung Fluid ◽  
Extravascular Volume ◽  
Dilution Curves

The extravascular volume of distribution for heat in the lung has been advocated for the measurement of lung water. The purpose of these experiments was to investigate how extremes of ventilation-perfusion mismatch influence this measurement. Twenty-six dogs were studied with right and left atrium-to-aorta thermal and dye-dilution curves before and 60 min after total right main-stem bronchial obstruction or microembolization of the pulmonary circulation with 0.275-mm glass beads. Whereas atelectasis had no influence on our measurements, embolization with 0.32 g/kg of beads decreased the detected pulmonary blood volume from 10.63 to 8.55 ml/kg and increased the extravascular thermal volume (ETV) from 9.89 to 10.99 ml/kg. Embolization with 0.65 g/kg decreased the detected ETV from 9.29 to 8.38 ml/kg, while the extravascular wet-to-dry weight ratio was increased, and the regression of postmortem extravascular mass on ETV differed from control. We conclude that microembolization but not atelectasis causes errors in the measurement of lung fluid when the thermodye technique is used. The errors are variable and depend on the degree of embolization.

Influence of Radioiodine Therapy on Urinary Iodine Excretion

1998 ◽  
Vol 37 (03) ◽  
pp. 107-112 ◽  
Author(s):  
I. Lauer ◽  
M. Bähre ◽  
E. Richter ◽  
B. Melier
Keyword(s):  
Time Course ◽  
Radioiodine Therapy ◽  
Urinary Iodine ◽  
Target Volume ◽  
Urinary Iodine Excretion ◽  
Urinary Creatinine ◽  
Iodine Excretion ◽  
Kinetics Of ◽  
Persistent Elevation ◽  
Benign Thyroid

Summary Aim: In 214 patients with benign thyroid diseases the time-course of urinary iodine excretion (UIE) was investigated in order to identify changes after radioiodine therapy (RITh). Method: UIE was measured photometrically (cerium-arsenite method) and related to urinary creatinine on the first and last day of the radioiodine test and then three days, seven days, four weeks, and six months after 1311 administration. Results: As compared with the level found immediately before radioiodine therapy, median UIE had almost doubled four weeks after therapy and was still significantly elevated six months after therapy. This increase correlated significantly with the target volume as measured by scintigraphy and sonography. Conclusions: The persistent elevation of UIE for months after RITh is a measure of treatment-induced damage to thyrocytes. Therefore, in view of the unfavourable kinetics of iodine that follow it, RITh should if possible be given via a single-dose regime.

Simultaneous Red Cell and Plasma Protein Indicator-Dilution Curves Across the Peripheral Circulation During Open-Heart Surgery

Circulation ◽  
1966 ◽  
Vol 33 (4s1) ◽  
Author(s):  
STANLEY GIANNELLI ◽  
STEPHEN M. AYRES ◽  
WILLIAM I. WOLFF ◽  
META BUEHLER ◽  
E. FOSTER CONKLIN
Keyword(s):  
Plasma Protein ◽  
Heart Surgery ◽  
Open Heart Surgery ◽  
Peripheral Circulation ◽  
Indicator Dilution ◽  
Red Cell ◽  
Open Heart ◽  
Dilution Curves

scholarly journals Simulating a Ground Truth for Transit Time Analysis of Indicator Dilution Curves

2020 ◽  
Vol 6 (3) ◽  
pp. 268-271
Author(s):  
Michael Reiß ◽  
Ady Naber ◽  
Werner Nahm
Keyword(s):  
Transit Time ◽  
Sampling Rate ◽  
Ground Truth ◽  
Indicator Dilution ◽  
Cross Sectional ◽  
In Vivo Measurements ◽  
Multiple Indicator Dilution ◽  
Transit Times ◽  
Dilution Curves

AbstractTransit times of a bolus through an organ can provide valuable information for researchers, technicians and clinicians. Therefore, an indicator is injected and the temporal propagation is monitored at two distinct locations. The transit time extracted from two indicator dilution curves can be used to calculate for example blood flow and thus provide the surgeon with important diagnostic information. However, the performance of methods to determine the transit time Δt cannot be assessed quantitatively due to the lack of a sufficient and trustworthy ground truth derived from in vivo measurements. Therefore, we propose a method to obtain an in silico generated dataset of differently subsampled indicator dilution curves with a ground truth of the transit time. This method allows variations on shape, sampling rate and noise while being accurate and easily configurable. COMSOL Multiphysics is used to simulate a laminar flow through a pipe containing blood analogue. The indicator is modelled as a rectangular function of concentration in a segment of the pipe. Afterwards, a flow is applied and the rectangular function will be diluted. Shape varying dilution curves are obtained by discrete-time measurement of the average dye concentration over different cross-sectional areas of the pipe. One dataset is obtained by duplicating one curve followed by subsampling, delaying and applying noise. Multiple indicator dilution curves were simulated, which are qualitatively matching in vivo measurements. The curves temporal resolution, delay and noise level can be chosen according to the requirements of the field of research. Various datasets, each containing two corresponding dilution curves with an existing ground truth transit time, are now available. With additional knowledge or assumptions regarding the detection-specific transfer function, realistic signal characteristics can be simulated. The accuracy of methods for the assessment of Δt can now be quantitatively compared and their sensitivity to noise evaluated.

scholarly journals Changes in J chain and mu chain RNA expression as a function of B cell differentiation.

1984 ◽  
Vol 160 (3) ◽  
pp. 877-892 ◽  
Author(s):  
G Lamson ◽  
M E Koshland
Keyword(s):  
B Cell ◽  
Time Course ◽  
Rna Synthesis ◽  
Rna Expression ◽  
B Cell Differentiation ◽  
Activated Lymphocytes ◽  
J Chain ◽  
Pattern Characteristic ◽  
Kinetics Of ◽  
Lymphoid Cell Lines

The time course of differentiative events in the pentamer IgM response was examined by following the expression of J chain and mu chain RNA and their protein products in mitogen-stimulated lymphocytes. The analyses showed that the shift to mus RNA synthesis begins shortly after stimulation and precedes proliferation of the cells and any increase in mu RNA levels. In contrast, expression of J chain RNA and the amplification of J chain and mus message are late events that coincide with a phase of rapid proliferation and with the secretion of pentamer IgM antibody. The kinetics of J and mu chain RNA expression observed in normal lymphocytes were supported by analyses of lymphoid cell lines. B lymphomas were found to display the RNA pattern characteristic of early-activated lymphocytes, i.e., a partial shift to mus RNA production and no J chain RNA, whereas IgM-secreting lines resembled late-activated lymphocytes in their expression of high levels of both mus and J chain mRNA. Moreover, the kinetics of J and mus chain RNA expression correlates with the sequential action of B cell lymphokines in the induction of the pentamer IgM response. This correlation suggests that the successive differentiative changes are triggered by successive membrane stimuli.

scholarly journals Relative Effects of Heart Chambers, Lungs, and Mitral Insufficiency on the Shape of Indicator Dilution Curves

1959 ◽  
Vol 7 (1) ◽  
pp. 141-146 ◽  
Author(s):  
RICHARD W. EMANUEL ◽  
WILLIAM W. LACY ◽  
ELLIOT V. NEWMAN
Keyword(s):  
Indicator Dilution ◽  
Mitral Insufficiency ◽  
Dilution Curves

Detection and quantification of small left-to-right shunts by the phase-plane method

1983 ◽  
Vol 244 (4) ◽  
pp. H622-H627
Author(s):  
A. Fonseca-Costa ◽  
P. Magrassi ◽  
W. A. Zin ◽  
L. J. Romeo
Keyword(s):  
Sampling Method ◽  
Phase Plane ◽  
Sampling Site ◽  
Indicator Dilution ◽  
Terminal Portion ◽  
Systemic Artery ◽  
Anesthetized Dogs ◽  
Phase Plane Method ◽  
High Level ◽  
Dilution Curves

Sixty-five pairs of indicator-dilution curves were obtained in five anesthetized dogs. After the injection of indocyanine dye into the left atrium, blood was simultaneously sampled through dichromatic cuvette densitometers from the femoral artery and the distal pulmonary artery. Dye-dilution curves were recorded from dogs with normal cardiovascular systems and after the surgical production of left-to-right shunts of different magnitudes. The percent of blood shunting was calculated according to the double sampling method and compared with a new method based on the deviation observed in the terminal portion of the indicator-dilution phase-plane loop. A high level of correlation was observed between both methods (r = 0.961). The phase plane shows its utility in the quantification of small left-to-right shunts. The use of only one sampling site at a peripheral systemic artery is an important advantage because there is complete mixture between shunted and unshunted blood.

Coordinate induction of metallothioneins I and II in rodent cells by UV irradiation

1988 ◽  
Vol 8 (11) ◽  
pp. 4716-4720
Author(s):  
A J Fornace ◽  
H Schalch ◽  
I Alamo
Keyword(s):  
Sequence Analysis ◽  
Uv Irradiation ◽  
Time Course ◽  
Human Fibroblasts ◽  
Chinese Hamster ◽  
Cdna Clones ◽  
X Rays ◽  
General Stress Response ◽  
Rapid Induction ◽  
Kinetics Of

Sequence analysis of Chinese hamster V79 lung fibroblast cDNA clones, which code for UV radiation-inducible transcripts, revealed that many of the clones corresponded to metallothioneins (MTs) I and II. A third cDNA clone, DDIU4, was found also to code for a similar-size UV-inducible transcript which was unrelated to MT by both sequence analysis and kinetics of induction. MTI and MTII RNAs rapidly increased in V79 cells within 1 h after UV irradiation, and maximum induction was seen by 4 h. This rapid induction of MT RNA by UV irradiation was not observed in human fibroblasts. MTI and MTII were coordinately induced in both time course and dose-response experiments, although the induction of MTII, up to 30-fold, was three to four times greater than that of MTI. The induction of MT did not appear to be a general stress response, since no increase occurred after exposure to X rays or H2O2.

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