Scaling of blood parameters in mammals

Prothero, John

doi:10.1016/0300-9629(80)90255-8

Cited by 85 publications

(47 citation statements)

References 83 publications

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“…Pharmacokinetic Analysis of the Plasma Concentration-Time Data-To demonstrate further that IFN-␥ injected either alone or bound to heparin behaved differently, several pharmacokinetic parameters were determined ( Table I). Assuming that the blood volume represents 8% of the body weight (21) and therefore should be 40 ml, 10 5 cpm/ml was expected at the time of injection, in close agreement with the experimental data and the applied model. Furthermore, the blood volumes (V b ) calculated from the exponential equation coefficients were also in the same range (40 -43 ml; Table I).…”

Section: Methodssupporting

confidence: 72%

Heparin Decreases the Blood Clearance of Interferon-γ and Increases Its Activity by Limiting the Processing of Its Carboxyl-terminal Sequence

Lortat‐Jacob

Baltzer

Grimaud

1996

Journal of Biological Chemistry

126

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Interferon-␥ (IFN-␥) binds with high affinity to heparan sulfate and heparin molecules through its carboxylterminal domain. In vivo, IFN-␥ is eliminated from the bloodstream with a half-life (t 1/2 ) of 1.1 min, due to binding to heparan sulfate. Unbound IFN-␥ is cleaved rapidly at the carboxyl-terminal side, a process that removes at least 18 amino acids and inactivates the cytokine. When bound to heparin, the plasma clearance of IFN-␥ is decreased greatly (t 1/2 ‫؍‬ 99 min), and the area under the curve obtained with IFN-␥ alone represented only 15% of that obtained with injected IFN-␥ bound to heparin. Furthermore, the binding of heparin to IFN-␥ limits the extent of its carboxyl-terminal domain degradation to less than 10 amino acids. Importantly, this process increases the cytokine activity by as much as 600%. These data demonstrate that the blood clearance of the cytokine is a non-receptor-mediated process and that in vivo the local concentration of heparan sulfate/ heparin-like molecules regulates IFN-␥ activity by a unique mechanism involving a controlled processing of its carboxyl-terminal sequence.

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Section: Methodssupporting

confidence: 72%

Heparin Decreases the Blood Clearance of Interferon-γ and Increases Its Activity by Limiting the Processing of Its Carboxyl-terminal Sequence

Lortat‐Jacob

Baltzer

Grimaud

1996

Journal of Biological Chemistry

126

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“…Both these numbers are in reasonable agreement with data, considering the rough estimates involved in the calculation. This is the only result here presented that depends on the actual value of the branching number n: Data show that the total blood volume is proportional to the body mass (Stahl, 1967, Prothero, 1980. If this holds also for the arterial blood volume, our model predicts allometric scaling exponents as in Table 1.…”

Section: Human Arterial Systemmentioning

confidence: 49%

“…The allometric scaling of corresponding aorta quantities also agrees well with data, suggesting that the model is applicable to all mammals. Blood volume V 1 1 :02 (Stahl, 1967), 0:99 (Prothero, 1980) Capillary density N c =M À 2 17 ¼ À0:12 À0:14 (Schmidt-Nielsen & Pennycuick, 1961), À0:14 to þ0:14 (Hoppeler et al, 1981) Aorta radius R 0 6 17 ¼ 0:35 0:41 (Clark, 1927), 0.36 (Holt et al, 1981) Aorta length L 0 5 17 ¼ 0:29 0:32 (Holt et al, 1981) Aorta pressure P 0 0 E0 (Schmidt-Nielsen, 1984;Calder, 1984) Volume flow F 15 17 ¼ 0:88 0:81 (Stahl, 1967), 0.79 (Holt et al, 1968), 0:75 (White et al, 1968) Note: The exponent for blood volume is fixed to 1, and the other exponents are model predictions. Data are from the compilations in Calder (1984) and Schmidt-Nielsen (1984).…”

Section: Human Arterial Systemmentioning

confidence: 99%

A Simple Model for the Arterial System

Bengtsson

Edén

2003

Journal of Theoretical Biology

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“…35,42 In these studies, aortic diameter scales with body mass with an allometric exponent of Ϸ0.4, [42][43][44] whereas capillary density appears to be relatively invariant with regard to body size. 42,45,46 Blood volume appears to scale ratiometrically with body mass, 42,47,48 which provides a rationale for scaling intravenous infusions to this variable. There has been little empirical research to date, however, to quantify allometric scaling properties of vascular structure over the range of body sizes in humans.…”

Section: Evidence For Allometric Scaling Of Cardiovascular Structurementioning

confidence: 99%

Does Size Matter?

et al. 2008

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Abstract-Extensive evidence is available that cardiovascular structure and function, along with other biological properties that span the range of organism size and speciation, scale with body size. Although appreciation of such factors is commonplace in pediatrics, cardiovascular measurements in the adult population, with similarly wide variation in body size, are rarely corrected for body size. The patient is a very tall 23-yearold competitive rower with a height of 203 cm and weight of 100 kg referred to the clinic for preparticipation athletic screening. He has never experienced syncope, palpitations, or chest pain during exertion and has no significant past medical history, but he occasionally feels "light-headed" at the end of an exhaustive competitive workout. He has no family history of sudden cardiac death or of premature cardiovascular disease. He is actively training 5 to 6 hours per day, 6 days per week in preparation for the upcoming Olympic Games. The examination is remarkable only for a soft systolic ejection murmur, cardiomegaly, and a third heart sound. An ECG is ordered, which is remarkable for sinus bradycardia, a 15-mV R wave in lead aVL, and R-wave voltage in lead V 5 plus S-wave voltage in lead V 1 totaling 46 mV. On a follow-up echocardiogram, septal and posterior wall thicknesses of 14.5 mm are observed with a left ventricular (LV) internal dimension in diastole of 53 mm. No significant obstructive LV outflow pattern is present, and wall thickness appears symmetrical. On the basis of current echocardiographic criteria, this patient is in the "gray zone" between physiological and pathological hypertrophy. His nonspecific symptoms and lack of other contributing history add to the ambiguity in diagnosis. Clinical Vignette No. 2:The patient is a 66-year-old woman who has a height of 155 cm and a body mass of 49 kg.She has a history of hyperlipidemia and abdominal aortic aneurysm. She comes to the clinic for her yearly ultrasound follow-up, which shows a maximum aneurysm diameter of 50 mm. She is in a "gray zone" in which neither surgical correction nor watchful waiting is definitively indicated.Considerable evidence is available that biological processes from metabolic enzyme activity 1 to plant and animal metabolic rates 2-4 to cancer metastasis 5 scale with body size over the entire range of organism size and speciation. Cardiovascular structural and functional variables also scale with body size. Compare, for instance, the blue whale, which has a heart mass of 600 kg and a resting heart rate of 6 bpm, with the smallest mammal, the shrew, which has a heart mass of 12 mg and a resting heart rate of up to 1200 bpm. 6 Despite the clear relationship between body size and cardiovascular dimensions and functional parameters, the practice of scaling cardiovascular measurements is poorly applied in adult clinical cardiology. This contrasts with pediatric medicine, in which measurements are universally indexed to body size. The intuitive idea that body growth implies a greater need for scaling in pe...

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Scaling of blood parameters in mammals

Cited by 85 publications

References 83 publications

Heparin Decreases the Blood Clearance of Interferon-γ and Increases Its Activity by Limiting the Processing of Its Carboxyl-terminal Sequence

Heparin Decreases the Blood Clearance of Interferon-γ and Increases Its Activity by Limiting the Processing of Its Carboxyl-terminal Sequence

A Simple Model for the Arterial System

Does Size Matter?

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