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Michael B Thompson - One of the best experts on this subject based on the ideXlab platform.
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placental nutrition in the viviparous lizard niveoscincus metallicus the influence of placental type
The Journal of Experimental Biology, 1999Co-Authors: Michael B Thompson, Brian K Speake, Kylie J Russell, Ruth J Mccartney, James R Stewart, Peter F. SuraiAbstract:The ion, energy, lipid, nitrogen and fat-soluble vitamin contents of freshly ovulated eggs and Neonates of the viviparous lizard Niveoscincus metallicus were measured to quantify uptake of nutrients across the placenta. This species is particularly interesting because it has a chorio-allantoic placenta that is intermediate in complexity compared to viviparous species that have been the focus of other studies. Newly ovulated eggs have a wet mass of 79.6+/−4.6 mg and a dry mass of 41.8+/−2.8 mg, compared to the Neonates that have a wet mass of 224.2+/−8.2 mg and dry mass of 37.9+/−1.2 mg. Thus, there is no significant net uptake of dry matter across the placenta. Neonates have significantly less lipid (6.2+/−0.4 mg) than eggs (12.7+/−0.5 mg), but no significant difference in nitrogen (4.1+/−0.3 mg) compared to eggs (4.5+/−0.2 mg). Energy densities reflect the protein and lipid composition and the relative dry masses of the eggs and Neonates. There is significantly more energy (1029.1+/−80.0 J) in the egg than in the neonate (858.2+/−38.6 J). The increase in the ash content of the Neonates (2.9+/−0.2 mg) compared to fresh eggs (2.1+/−0.3 mg) was not significant, even though there was an approximately threefold increase in the amount of sodium (0.11+/−0.01 mg in Neonates, 0.34+/−0.01 mg in eggs) and potassium (0.12+/−0.017 in Neonates, 0.40+/−0.01 mg in eggs) in Neonates compared to eggs. There was no significant uptake of calcium and magnesium during development. The egg lipids consisted of triacylglycerol (66.7+/−2.3 %), phospholipid (18.9+/−0.7 %), cholesteryl ester (4.9+/−1.6 %) and free cholesterol (5.6+/−1.5 %). The egg phospholipid contained comparatively high proportions of arachidonic and eicosapentanoic acids but low levels of docosahexaenoic acid (DHA), whereas the phospholipid of the neonate was greatly enriched in DHA. In the egg, the predominant vitamin E was (α)-tocopherol (62.6+/−3.4 mg g(−)(1)), although there was some (γ)-tocotrienol (3.5+/−0.3 mg g(−)(1)), and vitamin A was present (1.5+/−0.2 mg g(−)(1)). The ratio of neonate dry mass to egg dry mass of N. metallicus (0.91) lies between that of species with type I (0.78) and type III (1.70) chorio-allantoic placentae, confirming our conclusion that the placenta of N. metallicus is functionally intermediate, as well as intermediate in complexity, between these other two types.
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placental transfer of nutrients during gestation in the viviparous lizard pseudemoia spenceri
Journal of Comparative Physiology B-biochemical Systemic and Environmental Physiology, 1999Co-Authors: Michael B Thompson, Brian K Speake, Kylie J Russell, James R Stewart, Ruth J MccartneyAbstract:Energy, ionic, protein and lipid contents and fatty acid profiles for the major lipid classes of freshly ovulated eggs and Neonates of the viviparous lizard, Pseudemoia spenceri, were measured. Litter size is 1.7 ± 0.1, with larger females producing larger Neonates. Placentotrophy results in approximately 23% more dry matter in the Neonates than in the fresh egg. The increase in the quantity of protein and lipid during development is not significant and is reflected in the similarity of energy densities of eggs and Neonates. As a percentage of dry matter, Neonates have slightly lower proportions of lipid and protein than eggs because of significant uptake of ash, calcium, potassium and sodium, but not of magnesium, across the placenta. The amounts of triacylglycerol and phospholipid are not significantly different between the egg and the neonate, but Neonates contain significantly more cholesterol and cholesteryl ester. The amounts of the major fatty acids, palmitic and oleic acids, recovered from the total lipids of the neonate do not differ significantly from the amounts present in the egg lipids, but the Neonates contain significantly less linoleic and α-linolenic acids and more palmitoleic, stearic and arachidonic acids than the eggs. The amount of docosahexaenoic acid recovered from the lipids of the neonate is 2.6-times greater than the amount initially present in the egg. P. spenceri has a relatively larger egg and a smaller reliance on placentotrophy than other species in the same genus, all of which have a similar placental morphology. Nevertheless, the pattern of embryonic nutrition includes both obligative and facultative placentotrophy. All the major components of yolk of oviparous species are present in eggs of P. spenceri, but most are augmented during development by placental transfer.
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placental nutrition in a viviparous lizard pseudemoia pagenstecheri with a complex placenta
Journal of Zoology, 1999Co-Authors: Michael B Thompson, Brian K Speake, Kylie J Russell, Ruth J Mccartney, James R Stewart, Peter F. SuraiAbstract:The composition of egg yolks and Neonates of the viviparous lizard, Pseudemoia pagenstecheri, one of the most placentotrophic reptiles studied to date, are described. Neonates (43.3 ± 5.2 mg) have twice the dry mass of the initial eggs (22.0 ± 1.9 mg). The protein content of Neonates (29.1 ± 1.1 mg) is more than twice that of eggs (12.2 ± 1.1 mg), while the energy content (908.1 ± 107.4 J) is 1.6 times higher than that of the egg (565.0 ± 42.9 J). The energy densities of eggs (27.5 kJ g−1) and Neonates (23.1 ± 0.3 kJ g−1) are similar to the energy densities of eggs and Neonates of oviparous species. The total ash per neonate (4.1 ± 0.4 mg) is three times greater than that of the egg contents (1.4 ± 0.2). Neonates contain significantly more calcium, sodium and potassium, but not magnesium, than do eggs. Thus, the placenta has a quantitatively important role in supplying nutrients for the embryo. The proportions of triacylglycerol (66%), phospholipid (19%), and free cholesterol (5%) in the eggs are similar to those in eggs of birds and crocodilians, but the proportion of cholesteryl esters (7%) is much higher in eggs of P. pagenstecheri. The proportion of docosahexaenoic acid in the egg phospholipid is relatively low (1.4%) but rises to 5.4% in the neonate. The eggs contain vitamin E (mainly in the form of α-tocopherol) and vitamin A, but no detectable carotenoids. The overall composition of the eggs is not substantially different from that of oviparous species, suggesting that the small egg size relative to neonate size is a result of a reduction in egg size rather than modification by omission of some nutrients from the yolk. The pattern of placental nutrient provision of P. pagenstecheri contains both an obligate and a facultative component suggesting that enhancement of offspring quality through facultative placentotrophy is a general characteristic of placental reptiles independent of pattern of embryonic nutrient provision.
Ruth J Mccartney - One of the best experts on this subject based on the ideXlab platform.
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placental nutrition in the viviparous lizard niveoscincus metallicus the influence of placental type
The Journal of Experimental Biology, 1999Co-Authors: Michael B Thompson, Brian K Speake, Kylie J Russell, Ruth J Mccartney, James R Stewart, Peter F. SuraiAbstract:The ion, energy, lipid, nitrogen and fat-soluble vitamin contents of freshly ovulated eggs and Neonates of the viviparous lizard Niveoscincus metallicus were measured to quantify uptake of nutrients across the placenta. This species is particularly interesting because it has a chorio-allantoic placenta that is intermediate in complexity compared to viviparous species that have been the focus of other studies. Newly ovulated eggs have a wet mass of 79.6+/−4.6 mg and a dry mass of 41.8+/−2.8 mg, compared to the Neonates that have a wet mass of 224.2+/−8.2 mg and dry mass of 37.9+/−1.2 mg. Thus, there is no significant net uptake of dry matter across the placenta. Neonates have significantly less lipid (6.2+/−0.4 mg) than eggs (12.7+/−0.5 mg), but no significant difference in nitrogen (4.1+/−0.3 mg) compared to eggs (4.5+/−0.2 mg). Energy densities reflect the protein and lipid composition and the relative dry masses of the eggs and Neonates. There is significantly more energy (1029.1+/−80.0 J) in the egg than in the neonate (858.2+/−38.6 J). The increase in the ash content of the Neonates (2.9+/−0.2 mg) compared to fresh eggs (2.1+/−0.3 mg) was not significant, even though there was an approximately threefold increase in the amount of sodium (0.11+/−0.01 mg in Neonates, 0.34+/−0.01 mg in eggs) and potassium (0.12+/−0.017 in Neonates, 0.40+/−0.01 mg in eggs) in Neonates compared to eggs. There was no significant uptake of calcium and magnesium during development. The egg lipids consisted of triacylglycerol (66.7+/−2.3 %), phospholipid (18.9+/−0.7 %), cholesteryl ester (4.9+/−1.6 %) and free cholesterol (5.6+/−1.5 %). The egg phospholipid contained comparatively high proportions of arachidonic and eicosapentanoic acids but low levels of docosahexaenoic acid (DHA), whereas the phospholipid of the neonate was greatly enriched in DHA. In the egg, the predominant vitamin E was (α)-tocopherol (62.6+/−3.4 mg g(−)(1)), although there was some (γ)-tocotrienol (3.5+/−0.3 mg g(−)(1)), and vitamin A was present (1.5+/−0.2 mg g(−)(1)). The ratio of neonate dry mass to egg dry mass of N. metallicus (0.91) lies between that of species with type I (0.78) and type III (1.70) chorio-allantoic placentae, confirming our conclusion that the placenta of N. metallicus is functionally intermediate, as well as intermediate in complexity, between these other two types.
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placental transfer of nutrients during gestation in the viviparous lizard pseudemoia spenceri
Journal of Comparative Physiology B-biochemical Systemic and Environmental Physiology, 1999Co-Authors: Michael B Thompson, Brian K Speake, Kylie J Russell, James R Stewart, Ruth J MccartneyAbstract:Energy, ionic, protein and lipid contents and fatty acid profiles for the major lipid classes of freshly ovulated eggs and Neonates of the viviparous lizard, Pseudemoia spenceri, were measured. Litter size is 1.7 ± 0.1, with larger females producing larger Neonates. Placentotrophy results in approximately 23% more dry matter in the Neonates than in the fresh egg. The increase in the quantity of protein and lipid during development is not significant and is reflected in the similarity of energy densities of eggs and Neonates. As a percentage of dry matter, Neonates have slightly lower proportions of lipid and protein than eggs because of significant uptake of ash, calcium, potassium and sodium, but not of magnesium, across the placenta. The amounts of triacylglycerol and phospholipid are not significantly different between the egg and the neonate, but Neonates contain significantly more cholesterol and cholesteryl ester. The amounts of the major fatty acids, palmitic and oleic acids, recovered from the total lipids of the neonate do not differ significantly from the amounts present in the egg lipids, but the Neonates contain significantly less linoleic and α-linolenic acids and more palmitoleic, stearic and arachidonic acids than the eggs. The amount of docosahexaenoic acid recovered from the lipids of the neonate is 2.6-times greater than the amount initially present in the egg. P. spenceri has a relatively larger egg and a smaller reliance on placentotrophy than other species in the same genus, all of which have a similar placental morphology. Nevertheless, the pattern of embryonic nutrition includes both obligative and facultative placentotrophy. All the major components of yolk of oviparous species are present in eggs of P. spenceri, but most are augmented during development by placental transfer.
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placental nutrition in a viviparous lizard pseudemoia pagenstecheri with a complex placenta
Journal of Zoology, 1999Co-Authors: Michael B Thompson, Brian K Speake, Kylie J Russell, Ruth J Mccartney, James R Stewart, Peter F. SuraiAbstract:The composition of egg yolks and Neonates of the viviparous lizard, Pseudemoia pagenstecheri, one of the most placentotrophic reptiles studied to date, are described. Neonates (43.3 ± 5.2 mg) have twice the dry mass of the initial eggs (22.0 ± 1.9 mg). The protein content of Neonates (29.1 ± 1.1 mg) is more than twice that of eggs (12.2 ± 1.1 mg), while the energy content (908.1 ± 107.4 J) is 1.6 times higher than that of the egg (565.0 ± 42.9 J). The energy densities of eggs (27.5 kJ g−1) and Neonates (23.1 ± 0.3 kJ g−1) are similar to the energy densities of eggs and Neonates of oviparous species. The total ash per neonate (4.1 ± 0.4 mg) is three times greater than that of the egg contents (1.4 ± 0.2). Neonates contain significantly more calcium, sodium and potassium, but not magnesium, than do eggs. Thus, the placenta has a quantitatively important role in supplying nutrients for the embryo. The proportions of triacylglycerol (66%), phospholipid (19%), and free cholesterol (5%) in the eggs are similar to those in eggs of birds and crocodilians, but the proportion of cholesteryl esters (7%) is much higher in eggs of P. pagenstecheri. The proportion of docosahexaenoic acid in the egg phospholipid is relatively low (1.4%) but rises to 5.4% in the neonate. The eggs contain vitamin E (mainly in the form of α-tocopherol) and vitamin A, but no detectable carotenoids. The overall composition of the eggs is not substantially different from that of oviparous species, suggesting that the small egg size relative to neonate size is a result of a reduction in egg size rather than modification by omission of some nutrients from the yolk. The pattern of placental nutrient provision of P. pagenstecheri contains both an obligate and a facultative component suggesting that enhancement of offspring quality through facultative placentotrophy is a general characteristic of placental reptiles independent of pattern of embryonic nutrient provision.
Peter F. Surai - One of the best experts on this subject based on the ideXlab platform.
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placental nutrition in the viviparous lizard niveoscincus metallicus the influence of placental type
The Journal of Experimental Biology, 1999Co-Authors: Michael B Thompson, Brian K Speake, Kylie J Russell, Ruth J Mccartney, James R Stewart, Peter F. SuraiAbstract:The ion, energy, lipid, nitrogen and fat-soluble vitamin contents of freshly ovulated eggs and Neonates of the viviparous lizard Niveoscincus metallicus were measured to quantify uptake of nutrients across the placenta. This species is particularly interesting because it has a chorio-allantoic placenta that is intermediate in complexity compared to viviparous species that have been the focus of other studies. Newly ovulated eggs have a wet mass of 79.6+/−4.6 mg and a dry mass of 41.8+/−2.8 mg, compared to the Neonates that have a wet mass of 224.2+/−8.2 mg and dry mass of 37.9+/−1.2 mg. Thus, there is no significant net uptake of dry matter across the placenta. Neonates have significantly less lipid (6.2+/−0.4 mg) than eggs (12.7+/−0.5 mg), but no significant difference in nitrogen (4.1+/−0.3 mg) compared to eggs (4.5+/−0.2 mg). Energy densities reflect the protein and lipid composition and the relative dry masses of the eggs and Neonates. There is significantly more energy (1029.1+/−80.0 J) in the egg than in the neonate (858.2+/−38.6 J). The increase in the ash content of the Neonates (2.9+/−0.2 mg) compared to fresh eggs (2.1+/−0.3 mg) was not significant, even though there was an approximately threefold increase in the amount of sodium (0.11+/−0.01 mg in Neonates, 0.34+/−0.01 mg in eggs) and potassium (0.12+/−0.017 in Neonates, 0.40+/−0.01 mg in eggs) in Neonates compared to eggs. There was no significant uptake of calcium and magnesium during development. The egg lipids consisted of triacylglycerol (66.7+/−2.3 %), phospholipid (18.9+/−0.7 %), cholesteryl ester (4.9+/−1.6 %) and free cholesterol (5.6+/−1.5 %). The egg phospholipid contained comparatively high proportions of arachidonic and eicosapentanoic acids but low levels of docosahexaenoic acid (DHA), whereas the phospholipid of the neonate was greatly enriched in DHA. In the egg, the predominant vitamin E was (α)-tocopherol (62.6+/−3.4 mg g(−)(1)), although there was some (γ)-tocotrienol (3.5+/−0.3 mg g(−)(1)), and vitamin A was present (1.5+/−0.2 mg g(−)(1)). The ratio of neonate dry mass to egg dry mass of N. metallicus (0.91) lies between that of species with type I (0.78) and type III (1.70) chorio-allantoic placentae, confirming our conclusion that the placenta of N. metallicus is functionally intermediate, as well as intermediate in complexity, between these other two types.
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placental nutrition in a viviparous lizard pseudemoia pagenstecheri with a complex placenta
Journal of Zoology, 1999Co-Authors: Michael B Thompson, Brian K Speake, Kylie J Russell, Ruth J Mccartney, James R Stewart, Peter F. SuraiAbstract:The composition of egg yolks and Neonates of the viviparous lizard, Pseudemoia pagenstecheri, one of the most placentotrophic reptiles studied to date, are described. Neonates (43.3 ± 5.2 mg) have twice the dry mass of the initial eggs (22.0 ± 1.9 mg). The protein content of Neonates (29.1 ± 1.1 mg) is more than twice that of eggs (12.2 ± 1.1 mg), while the energy content (908.1 ± 107.4 J) is 1.6 times higher than that of the egg (565.0 ± 42.9 J). The energy densities of eggs (27.5 kJ g−1) and Neonates (23.1 ± 0.3 kJ g−1) are similar to the energy densities of eggs and Neonates of oviparous species. The total ash per neonate (4.1 ± 0.4 mg) is three times greater than that of the egg contents (1.4 ± 0.2). Neonates contain significantly more calcium, sodium and potassium, but not magnesium, than do eggs. Thus, the placenta has a quantitatively important role in supplying nutrients for the embryo. The proportions of triacylglycerol (66%), phospholipid (19%), and free cholesterol (5%) in the eggs are similar to those in eggs of birds and crocodilians, but the proportion of cholesteryl esters (7%) is much higher in eggs of P. pagenstecheri. The proportion of docosahexaenoic acid in the egg phospholipid is relatively low (1.4%) but rises to 5.4% in the neonate. The eggs contain vitamin E (mainly in the form of α-tocopherol) and vitamin A, but no detectable carotenoids. The overall composition of the eggs is not substantially different from that of oviparous species, suggesting that the small egg size relative to neonate size is a result of a reduction in egg size rather than modification by omission of some nutrients from the yolk. The pattern of placental nutrient provision of P. pagenstecheri contains both an obligate and a facultative component suggesting that enhancement of offspring quality through facultative placentotrophy is a general characteristic of placental reptiles independent of pattern of embryonic nutrient provision.
Yogeshvar N Kalia - One of the best experts on this subject based on the ideXlab platform.
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development of an in vitro model for premature neonatal skin biophysical characterization using transepidermal water loss
Journal of Pharmaceutical Sciences, 2004Co-Authors: Sekkat Nabila, Yogeshvar N Kalia, Richard H GuyAbstract:The objective was to develop an in vitro model for the developing skin of the premature neonate. Barriers of different levels of efficiency were produced by differentially tape-stripping the stratum corneum (SC) from the skin of excised porcine ears, and were characterized by measurements of transepidermal water loss (TEWL). In this way, it was possible to express the recorded TEWL as a function of percentage SC thickness (F) generating the following relationship: TEWL = 2.7 + 41.exp [- 0.028.F]. These data were then compared to previously published in vivo measurements of TEWL obtained from a population of premature Neonates at various post-conceptional ages (PCA). The latter conformed to a remarkably parallel relationship to that found in vitro with the porcine skin model, namely TEWL = 3.3 + 41.exp [-0.026.(PCA-160)]. It can be suggested, therefore, that the empirically adjusted PCA (i.e., PCA-160) correlates closely with the developing thickness of the neonate's SC. The corollary is that porcine skin, in vitro, tape-stripped to a particular level, can provide a barrier corresponding to a specific degree of neonate maturation and can serve, hence, as a useful tool with which to explore whether transdermal drug delivery in this unique patient population may be beneficial.
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development of an in vitro model for premature neonatal skin biophysical characterization using transepidermal water loss
Journal of Pharmaceutical Sciences, 2004Co-Authors: Nabila Sekkat, Yogeshvar N KaliaAbstract:Abstract The objective was to develop an in vitro model for the developing skin of the premature neonate. Barriers of different levels of efficiency were produced by differentially tape‐stripping the stratum corneum (SC) from the skin of excised porcine ears, and were characterized by measurements of transepidermal water loss (TEWL). In this way, it was possible to express the recorded TEWL as a function of percentage SC thickness (F) generating the following relationship: TEWL = 2.7 + 41.exp [− 0.028.F]. These data were then compared to previously published in vivo measurements of TEWL obtained from a population of premature Neonates at various post‐conceptional ages (PCA). The latter conformed to a remarkably parallel relationship to that found in vitro with the porcine skin model, namely TEWL = 3.3 + 41.exp [−0.026 · (PCA‐160)]. It can be suggested, therefore, that the empirically adjusted PCA (i.e., PCA‐160) correlates closely with the developing thickness of the neonate's SC. The corollary is that porcine skin, in vitro , tape‐stripped to a particular level, can provide a barrier corresponding to a specific degree of neonate maturation and can serve, hence, as a useful tool with which to explore whether transdermal drug delivery in this unique patient population may be beneficial. © 2004 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 93:2936–2940, 2004
Nabila Sekkat - One of the best experts on this subject based on the ideXlab platform.
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development of an in vitro model for premature neonatal skin biophysical characterization using transepidermal water loss
Journal of Pharmaceutical Sciences, 2004Co-Authors: Nabila Sekkat, Yogeshvar N KaliaAbstract:Abstract The objective was to develop an in vitro model for the developing skin of the premature neonate. Barriers of different levels of efficiency were produced by differentially tape‐stripping the stratum corneum (SC) from the skin of excised porcine ears, and were characterized by measurements of transepidermal water loss (TEWL). In this way, it was possible to express the recorded TEWL as a function of percentage SC thickness (F) generating the following relationship: TEWL = 2.7 + 41.exp [− 0.028.F]. These data were then compared to previously published in vivo measurements of TEWL obtained from a population of premature Neonates at various post‐conceptional ages (PCA). The latter conformed to a remarkably parallel relationship to that found in vitro with the porcine skin model, namely TEWL = 3.3 + 41.exp [−0.026 · (PCA‐160)]. It can be suggested, therefore, that the empirically adjusted PCA (i.e., PCA‐160) correlates closely with the developing thickness of the neonate's SC. The corollary is that porcine skin, in vitro , tape‐stripped to a particular level, can provide a barrier corresponding to a specific degree of neonate maturation and can serve, hence, as a useful tool with which to explore whether transdermal drug delivery in this unique patient population may be beneficial. © 2004 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 93:2936–2940, 2004
