The duration of the effectiveness of vitamin A at causing proximodistal duplication in regenerating limbs of the axolotl,Ambystoma mexicanum, in relation to whole body retinoid levels

1992 ◽  
Vol 264 (2) ◽  
pp. 189-195 ◽  
Author(s):  
Keith J. Johnson ◽  
Steven R. Scadding
Keyword(s):  
Vitamin A ◽  
Ambystoma Mexicanum ◽  
Whole Body

scholarly journals The “Super-Child” Approach Is Applied To Estimate Retinol Kinetics and Vitamin A Total Body Stores in Mexican Preschoolers

2020 ◽  
Vol 150 (6) ◽  
pp. 1644-1651 ◽  
Author(s):  
Veronica Lopez-Teros ◽  
Jennifer L Ford ◽  
Michael H Green ◽  
Brianda Monreal-Barraza ◽  
Lilian García-Miranda ◽  
...  
Keyword(s):  
Vitamin A ◽  
Corn Oil ◽  
Compartmental Analysis ◽  
Whole Body ◽  
Retinyl Acetate ◽  
Data Set ◽  
Mexican Children ◽  
Model Predictions ◽  
Total Body ◽  
Composite Data

ABSTRACT Background Retinol isotope dilution (RID) and model-based compartmental analysis are recognized techniques for assessing vitamin A (VA) status. Recent studies have shown that RID predictions of VA total body stores (TBS) can be improved by using modeling and that VA kinetics and TBS in children can be effectively studied by applying population modeling (“super-child” approach) to a composite data set. Objectives The objectives were to model whole-body retinol kinetics and predict VA TBS in a group of Mexican preschoolers using the super-child approach and to use model predictions of RID coefficients to estimate TBS by RID in individuals. Methods Twenty-four healthy Mexican children (aged 3–6 y) received an oral dose (2.96 μmol) of [13C10]retinyl acetate in corn oil. Blood samples were collected from 8 h to 21 d after dosing, with each child sampled at 4 d and at 1 other time. Composite data for plasma labeled retinol compared with time were analyzed using a 6-component model to obtain group retinol kinetic parameters and pool sizes. Model-predicted TBS was compared with mean RID predictions at 4 d; RID estimates at 4 d were compared with those calculated at 7–21 d. Results Model-predicted TBS was 1097 μmol, equivalent to ∼2.4 y-worth of VA; using model-derived coefficients, group mean RID-predicted TBS was 1096 μmol (IQR: 836–1492 μmol). TBS at 4 d compared with a later time was similar (P = 0.33). The model predicted that retinol spent 1.5 h in plasma during each transit and recycled to plasma 13 times before utilization. Conclusions The super-child modeling approach provides information on whole-body VA kinetics and can be used with RID to estimate TBS at any time between 4 and 21 d postdose. The high TBS predicted for these children suggests positive VA balance, likely due to large-dose VA supplements, and warrants further investigation.

scholarly journals Dietary Retinoic Acid Alters Vitamin A Kinetics in Both the Whole Body and in Specific Organs of Rats with Low Vitamin A Status

2005 ◽  
Vol 135 (4) ◽  
pp. 746-752 ◽  
Author(s):  
Christopher J. Cifelli ◽  
Joanne Balmer Green ◽  
Michael H. Green
Keyword(s):  
Retinoic Acid ◽  
Vitamin A ◽  
Whole Body ◽  
Vitamin A Status

scholarly journals Compartmental modeling of whole-body vitamin A kinetics in unsupplemented and vitamin A-retinoic acid-supplemented neonatal rats

2014 ◽  
Vol 55 (8) ◽  
pp. 1738-1749 ◽  
Author(s):  
Libo Tan ◽  
Amanda E. Wray ◽  
Michael H. Green ◽  
A. Catharine Ross
Keyword(s):  
Retinoic Acid ◽  
Vitamin A ◽  
Whole Body ◽  
Compartmental Modeling ◽  
Neonatal Rats

Skeletal patterns in the autopodium of native and regenerated limbs of the larval axolotl, Ambystoma mexicanum

1991 ◽  
Vol 69 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Steven R. Scadding
Keyword(s):  
Vitamin A ◽  
Significant Variation ◽  
Limb Regeneration ◽  
Ambystoma Mexicanum ◽  
Skeletal Patterning ◽  
Skeletal Pattern ◽  
Limb Pattern ◽  
Salamander Species

The purpose of this investigation was to study the autopodial skeletal patterns that are observed in native (never regenerated) and regenerated limbs of the larval axolotl, Ambystoma mexicanum. The axolotl is used widely in limb regeneration studies, and in the regenerating axolotl limb mesopodial patterns can be modified by such factors as vitamin A administration. It is also known that other salamander species show significant variation in autopodial skeletal patterning. Hence, it seemed important to determine the type and frequency of autopodial variants in both native limbs and those that have regenerated after amputation at either the stylopodial and zeugopodial levels. The results showed that native limbs exhibited a complete skeletal pattern in the majority of cases, but that variants involving loss of a phalange or reduction in the number of carpals or tarsals occurred frequently. Regenerated limb patterns were more variable than those seen in native limbs, and limbs regenerating from zeugopodial level amputations were more variable than those regenerating from stylopodial level amputation. The significance of these observations for the development and regeneration of limb pattern is discussed.

scholarly journals Assessment of tissue distribution and concentration of β-cryptoxanthin in response to varying amounts of dietary β-cryptoxanthin in the Mongolian gerbil

2013 ◽  
Vol 111 (6) ◽  
pp. 968-978 ◽  
Author(s):  
Michael R. La Frano ◽  
Chenghao Zhu ◽  
Betty J. Burri
Keyword(s):  
Vitamin A ◽  
Tissue Distribution ◽  
Mongolian Gerbil ◽  
Small Animal ◽  
Meriones Unguiculatus ◽  
Provitamin A ◽  
Whole Body ◽  
Tissue Storage ◽  
Group 13 ◽  
Treatment Groups

There is a general lack of knowledge regarding the absorption and tissue storage of the provitamin A carotenoid β-cryptoxanthin. The present study investigated the whole-body tissue distribution of β-cryptoxanthin in an appropriate small animal model, the Mongolian gerbil (Meriones unguiculatus), for human provitamin A carotenoid metabolism. After 5 d of carotenoid depletion, five gerbils were euthanised for baseline measurements. The remaining gerbils were placed in three weight-matched treatment groups (n 8). All the groups received 20 μg/d of β-cryptoxanthin from tangerine concentrate, while the second and third groups received an additional 20 and 40 μg/d of pure β-cryptoxanthin (CX40 and CX60), respectively, for 21 d. During the last 2 d of the study, urine and faecal samples of two gerbils from each treatment group were collected. β-Cryptoxanthin was detected in the whole blood, and in twelve of the fourteen tissues analysed. Most tissues resembled the liver, in which the concentrations of β-cryptoxanthin were significantly higher in the CX60 (17·8 (sem 0·7) μg/organ; P= 0·004) and CX40 (16·2 (sem 0·9) μg/organ; P= 0·006) groups than in the CX20 group (13·3 (sem 0·4) μg/organ). However, in intestinal tissues, the concentrations of β-cryptoxanthin increased only in the CX60 group. Despite elevated vitamin A concentrations in tissues at baseline due to pre-study diets containing high levels of vitamin A, β-cryptoxanthin maintained those vitamin A stores. These results indicate that β-cryptoxanthin is stored in many tissues, potentially suggesting that its functions are widespread.

scholarly journals Better Predictions of Vitamin A Total Body Stores by the Retinol Isotope Dilution Method Are Possible with Deeper Understanding of the Mathematics and by Applying Compartmental Modeling

2019 ◽  
Vol 150 (5) ◽  
pp. 989-993 ◽  
Author(s):  
Michael H Green ◽  
Joanne Balmer Green ◽  
Jennifer Lynn Ford
Keyword(s):  
Vitamin A ◽  
Isotope Dilution ◽  
Theoretical Data ◽  
Compartmental Analysis ◽  
Whole Body ◽  
Optimal Time ◽  
Isotope Dilution Method ◽  
Dilution Method ◽  
Model Based ◽  
Total Body

ABSTRACT Retinol isotope dilution (RID) is a well-accepted technique for assessing vitamin A status [i.e., total body stores (TBS)]. Here, in an effort to increase understanding of the method, we briefly review RID equations and discuss their included variables and their coefficients (i.e., assumptions that account for the efficiency of absorption of an orally administered tracer dose of vitamin A, mixing of the dose with endogenous vitamin A, and loss due to utilization). Then, we focus on contributions of another technique, model-based compartmental analysis and especially the “super-person” approach, that advance the RID method. Specifically, we explain how adding this modeling component, which involves taking 1 additional blood sample from each subject, provides population-specific estimates for the RID coefficients that can be used in the equation instead of values derived from the literature; using model-derived RID coefficients results in improved confidence in predictions of TBS for both a group and its individuals. We note that work is still needed to identify the optimal time for applying RID in different groups and to quantify vitamin A absorption efficiency. Finally, we mention other contributions of modeling, including the use of theoretical data to verify the accuracy of RID predictions and the additional knowledge that model-based compartmental analysis provides about whole-body vitamin A kinetics.

scholarly journals The Paired Deuterated Retinol Dilution Technique Can Be Used to Estimate the Daily Vitamin A Intake Required to Maintain a Targeted Whole Body Vitamin A Pool Size in Men

2011 ◽  
Vol 141 (3) ◽  
pp. 428-432 ◽  
Author(s):  
Marjorie J. Haskell ◽  
Kazi M. Jamil ◽  
Janet M. Peerson ◽  
Mohammed A. Wahed ◽  
Kenneth H. Brown
Keyword(s):  
Vitamin A ◽  
Pool Size ◽  
Whole Body ◽  
Dilution Technique ◽  
Daily Vitamin

scholarly journals Current Capabilities and Limitations of Stable Isotope Techniques and Applied Mathematical Equations in Determining Whole-Body Vitamin A Status

2016 ◽  
Vol 37 (2_suppl) ◽  
pp. S87-S103 ◽  
Author(s):  
Georg Lietz ◽  
Harold C. Furr ◽  
Bryan M. Gannon ◽  
Michael H. Green ◽  
Marjorie Haskell ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Vitamin A ◽  
Whole Body ◽  
Isotope Techniques ◽  
Vitamin A Status ◽  
Mathematical Equations

Vitamin A inhibits amphibian tail regeneration

1987 ◽  
Vol 65 (2) ◽  
pp. 457-459 ◽  
Author(s):  
Steven R. Scadding
Keyword(s):  
Retinoic Acid ◽  
Vitamin A ◽  
Xenopus Laevis ◽  
Ambystoma Mexicanum ◽  
Complete Inhibition ◽  
Notophthalmus Viridescens ◽  
Tail Regeneration ◽  
Dose Levels ◽  
Dose Dependent

The objective of this investigation was to determine what effect vitamin A had on tail regeneration in Notophthalmus viridescens adults, in Ambystoma mexicanum larvae, and in Xenopus laevis tadpoles. Notophthalmus viridescens and Ambystoma mexicanum had their tails amputated and then were treated with retinol palmitate by immersion in concentrations known to cause proximodistal duplications in regenerating limbs. Xenopus laevis tadpoles had their tails amputated and then were treated with either retinol palmitate by immersion, or with retinoic acid administered by implantation of silastin blocks containing retinoic acid. The results ranged from no effect at all at the lower dose levels used, to complete inhibition of tail regeneration at higher dose levels. The degree of inhibition of tail regeneration appeared to be dose dependent. In no case were any duplicated or accessory structures formed analogous to those observed in regenerating limbs. This result suggests that the morphogenetic processes involved in tail regeneration are at least in some ways different from those occurring in limbs, where a similar vitamin A treatment would cause proximodistal duplication or production of accessory limb structures.

scholarly journals A Compartmental Model Describing the Kinetics of β-Carotene and β-Carotene-Derived Retinol in Healthy Older Adults

2020 ◽  
Author(s):  
Michael H Green ◽  
Jennifer Lynn Ford ◽  
Joanne Balmer Green
Keyword(s):  
Vitamin A ◽  
Compartmental Model ◽  
Quantitative Information ◽  
Complex Model ◽  
Retinol Binding Protein ◽  
Whole Body ◽  
Published Data ◽  
Retinyl Acetate ◽  
Kinetics Of ◽  
Β Carotene

ABSTRACT Background Descriptive and quantitative information on β-carotene whole-body kinetics in humans is limited. Objectives Our objective was to advance the development of a physiologically based, working hypothesis compartmental model describing the metabolism of β-carotene and β-carotene-derived retinol. Methods We used model-based compartmental analysis (Simulation, Analysis and Modeling software) to analyze previously published data on plasma kinetics of [2H8]β-carotene, [2H4]β-carotene-derived retinol, and [2H8]retinyl acetate-derived retinol in healthy, older US adults (3 female, 2 male; 50–68 y); subjects were studied for 56 d after consuming doses of 11 μmol [2H8]β-carotene and, 3 d later, 9 μmol [2H8]retinyl acetate in oil. Results We developed a complex model for labeled β-carotene and β-carotene-derived retinol, as well as preformed vitamin A, using simulations to augment observed data during model calibration. The model predicts that mean (range) β-carotene absorption (bioavailability) was 9.5% (5.2–14%) and bioefficacy was 7.3% (3.6–14%). Of the absorbed β-carotene, 41% (25–58%) was packaged intact in chylomicrons and the balance was converted to retinol, with 58% (42–75%) transported as retinyl esters in chylomicrons and 0–2% by retinol-binding protein. Most (95%) chylomicron β-carotene was cleared by the liver. Later data revealed differences in the metabolism of retinyl acetate- versus β-carotene-derived retinol; data required that both β-carotene and derived retinol be recycled from extrahepatic tissues (e.g. adipose) in HDL. Of total bioconversion [73% (47–99%)], 82% occurred in the intestine, 17% in the liver, and 0.83% in other tissues. Conclusions Our model advances knowledge about whole-body β-carotene metabolism in healthy adults, including the kinetics of transport in all lipoprotein species, and suggests hypotheses to be tested in future studies, such as the possibility that retinol derived from hepatic conversion over a long period of time might contribute to plasma retinol homeostasis and total body vitamin A stores.

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