bluuebunny/crossref_metadata_2025_split huggingface dataset:
Histology of the extraembryonic membranes of an oviparous snake: Towards a reconstruction of basal squamate patterns
Authors: Blackburn Daniel G. , Johnson Amy R. , Petzold Jennifer L. 
Published: August 2003

AbstractAn understanding of the evolutionary morphology of extraembryonic membranes in reptiles requires information about oviparous as well as viviparous species. We are studying histology and ultrastructure of the extraembryonic membranes of snakes to clarify the evolutionary history of reptilian fetal membranes, including determination of basal (ancestral) ophidian and squamate patterns. Microscopic anatomy of the membranes of oviparous corn snakes (Elaphe guttata) was examined using light and electron microscopy. At mid – development the inner surface of the eggshell is lined by two extraembryonic membranes, the chorioallantois and the omphalallantoic membrane. The chorioallantois consists of a bilayered cuboidal epithelium that overlies the allantoic blood vessels. During development, allantoic capillaries become more abundant, and the chorionic epithelium thins, decreasing the diffusion distance for respiratory gas exchange. The abembryonic pole of the egg is delimited by a bilaminar omphalopleure and isolated yolk mass, the latter of which is lined on its inner face by the allantois. The isolated yolk mass regresses developmentally, and patches of yolk droplets become isolated and surrounded by allantoic blood vessels. By late development, the abembryonic hemisphere has been fully vascularized by allantoic vessels, forming a “secondary chorioallantois.” With regard to its extraembryonic membranes, Elaphe gutatta is similar to viviparous snakes. However, this species exhibits features that have not previously been reported among squamates, perhaps reflecting its oviparous reproductive habits. Morphological evidence for the uptake of eggshell material by epithelia of the chorion and omphalopleure suggests that the potential for absorption by extraembryonic membranes predates the origin of viviparity. J. Exp. Zool. 299A:48–58 2003. © 2003 Wiley‐Liss, Inc.
The marsupial placenta: A phylogenetic analysis
Authors: Freyer Claudia , Zeller Ulrich , Renfree Marilyn B. 
Published: August 2003

AbstractThe structure, physiology, and endocrinology of the yolk sac placenta of different marsupial groups is compared and phylogenetically analyzed to provide information on placental characters in the marsupial stem species. We conclude that the marsupial stem species possessed a functional yolk sac placenta. Histotrophic nutrition by uterine secretion decreased during late pregnancy and at least half of the yolk sac was vascularized at the time of shell coat rupture. Due to yolk sac fusion, the larger part of the avascular, bilaminar yolk sac could not serve as a placenta at late gestation in the polyovular marsupial stem species. The bilaminar yolk sac gained a relatively greater importance for nutrition in monovular australidelphians. In macropodids a greater proportion of the yolk sac remained bilaminar at the time of shell coat rupture than in the stem species. Another derived feature of macropodids is the sustained plasma progesterone synthesis that is in turn responsible for an extended secretory phase of the uterus and a lengthened gestation. The placenta of the marsupial stem species was probably capable of metabolising histo‐ and hemotrophes. Recognition of pregnancy during early stages of development is a derived character of macropodids that we suggest did not occur in the marsupial stem species. However, birth and birth behaviour were apparently induced by prostaglandins in the marsupial stem species. Although the yolk sac formed the definitive placenta, it is likely that the allantois provided a supplementary placental function in the marsupial stem species, but that the role of the allantois became progressively less important during the evolution of marsupial placentation. J. Exp. Zool. 299A:59–77 2003. © 2003 Wiley‐Liss, Inc.
Evolutionary transformations of chorioallantoic placental characters in rodentia with special reference to hystricognath species
Authors: Mess Andrea 
Published: August 2003

AbstractThe aim of this paper is to reconstruct the evolution of chorioallantoic placental characters in Rodentia. The analysis is based on pre‐existing hypotheses of rodent relationships and the tracing of character evolution. Data on 64 rodent species of 49 genera are derived from the literature. New results refer to the hystricognath species Petromus typicus A. Smith, 1831 and Octodon degus (Molina, 1782). This comprehensive analysis confirms that the stem species pattern of Rodentia is characterised by a haemochorial placenta which is divided horizontally. Inside the placental labyrinth, fetal vessels and their trophoblastic external border build up a network through which the maternal blood flows. The trophoblastic tissue is one‐layered, syncytial and possess a considerable surface extension. Within Rodentia, evolutionary transformations occurred on the macroscopic as well as the fine structural level. The results suggest that the stem species of Hystricognathi underwent transformations only on the macroscopic level, i.e., forming a ring‐shaped arrangement of placental regions with centrally situated maternal arteries and the acquisition of a subplacenta. By contrast, in Muridae the chorioallantoic placenta shows derived features only in regard to the fine structure of the labyrinth, i.e. the interhaemal membrane is modified in composition, and the fetal capillary endothelium is fenestrated. Geomyoidea underwent transformations on both levels. Macroscopically, their placenta is modified into a hillock shape. Microscopically, the interhaemal membrane is formed by the cytotrophoblast. In addition to the mentioned transformations, some aspects of other fetal membrane differentiation in Rodentia are briefly discussed. J. Exp. Zool. 299A:78–98, 2003. © 2003 Wiley‐Liss, Inc.
Development and evolution of the amniote integument: Current landscape and future horizon
Authors: Chuong Cheng‐Ming , Homberger Dominique G. 
Published: August 2003

AbstractThis special issue on the development and evolution of the amniote integument begins with a discussion of the adaptations to terrestrial conditions, the acquisition of water‐impermeability of the reptilian integument, and the initial formation of filamentous integumentary appendages that prepare the way towards avian flight. Recent feather fossils are reviewed, and a definition of feathers is developed. Hierarchical models are proposed for the formation of complex structures, such as feathers. Molecular signals that alter the phenotype of integumentary appendages at different levels of the hierarchy are presented. Tissue interactions and the roles of keratins in evolution are discussed and linked to their bio‐mechanical properties. The role of mechanical forces on patterning is explored. Elaborate extant feather variants are introduced. The regeneration/gene mis‐expression protocol for the chicken feather is established as a testable model for the study of biological structures. The adaptations of the mammalian distal limb end organs to terrestrial, arboreal and aquatic conditions are discussed. The development and cycling of hair are reviewed from a molecular perspective. These contributions reveal that the structure and function of diverse integumentary appendages are variations that are superimposed on a common theme, and that their formation is modular, hierarchical and cyclical. They further reveal that these mechanisms can be understood at the molecular level, and that an integrative and organismal approach to studying integumentary appendages is called for. We propose that future research should foster interdisciplinary approaches, pursue understanding at the cellular and molecular level, analyze interactions between the environment and genome, and recognize the contributions of variation in morphogenesis and evolution. J. Exp. Zool. (Mol. Dev. Evol.) 298B:1–11, 2003. © 2003 Wiley‐Liss, Inc.
The role of mechanical forces on the patterning of the avian feather‐bearing skin: A biomechanical analysis of the integumentary musculature in birds
Authors: Homberger Dominique G. , de Silva Kumudini N. 
Published: August 2003

AbstractThe integumentary musculature of birds consists of three distinct components. The smooth musculature comprises feather and apterial muscles, which form a continuous musculo‐elastic layer within the dermis. The feather muscles, which consistently include at least erectors and depressors, interconnect contour feathers within pterylae (i.e., feather tracts) along gridlines that are oriented diagonally to the longitudinal and transverse axes of the body. The apterial muscles interconnect pterylae by attaching to the contour feathers along their peripheries. The striated musculature is composed of individual subcutaneous muscles, most of which attach to contour feathers along the caudal periphery of pterylae A new integrative functional analysis of the integumentary musculature proposes how apterial muscles stabilize the pterylae and modulate the tension of the musculo‐elastic layer, and how subcutaneous muscles provide the initial stimulus for erector muscles being able to ruffle the contour feathers within pterylae. It also shows how the arrangement of the contour feathers and integumentary muscles reflects the stresses and strains that act on the avian skin. These mechanical forces are in effect not only in the adult, especially during flight, but may also be active during feather morphogenesis. The avian integument with its complex structural organization may, therefore, represent an excellent model for analyzing the nature of interactions between the environment and genetic material. The predictions of our model are testable, and our study demonstrates the relevance of integrated analyses of complex organs as mechanically coherent systems for evolutionary and developmental biology.J. Exp. Zool. (Mol. Dev. Evol.) 298B:123–139, 2003.© 2003 Wiley‐Liss, Inc.
Transcriptional activation of the metallothionein I gene by electric pulses in vivo: basis for the development of a new gene switch system
Authors: Rubenstrunk Anne , Orsini Cécile , Mahfoudi Abderrahim , Scherman Daniel 
Published: August 2003

AbstractBackgroundIn vivo gene transfer to skeletal muscle is a promising strategy for the treatment of muscular disorders and for the systemic delivery of therapeutic proteins. Nevertheless, for a safe and effective protein production, the spatial and temporal control of gene expression is critical. The existing regulating systems rely on the use of an exogenously regulatory protein and/or an inducer drug whose pharmacological properties are of major concerns for therapeutic applications in humans. Therefore, new strategies based on endogenous regulatable elements have been explored.MethodsGene expression profiles of skeletal muscle submitted or not to electrical pulses and harvested at different times were compared using the Affymetrix GeneChip technology. The endogenous metallothionein promoter was studied by Northern blot and semiquantitative and quantitative RT‐PCR. The inducibility of the metallothionein I promoter placed in a plasmid exogenous context was studied using the murine SEAP reporter gene.ResultsThe expression of metallothionein I mRNA is significantly increased 6 h after electric pulses delivery. This induction is transient. Identical MT‐I expression level is observed after several sequential series of pulses delivery. We demonstrated as well that the MT‐II promoter was sensitive to electric pulses delivery. Moreover, the metallothionein I promoter, placed in a plasmid context in front of a reporter gene, was also activated by the application of transient electric field.ConclusionsWe identified a promoter highly inducible by the controlled electric stimuli applied for electrotransfer experiments. The use of the metallothionein promoter is promising for the time‐control by physical stimuli of the expression of a therapeutic gene. Copyright © 2003 John Wiley & Sons, Ltd.
Adenovirus‐mediated gene transfer to adult mouse cardiomyocytes is selectively influenced by culture medium
Authors: Li Zhenbo , Sharma Ram V. , Duan Dongsheng , Davisson Robin L. 
Published: August 2003

AbstractBackgroundAs development of cardiac gene therapies progresses, virally mediated genetic manipulations in cultured cardiomyocytes has become an important experimental approach. While adenovirus (Ad)‐mediated gene transfer to neonatal and adult rat cardiomyocytes is well established, viral transduction of cultured adult mouse cardiomyocytes (AMCM) has been more difficult. This study was designed to test the hypothesis that culture medium is a critical determinant of efficient gene transfer in AMCM.MethodsAMCM from 8‐week‐old C57BL/6 mice were cultured in either minimum essential medium (MEM) or medium M199 and then infected with an Ad β‐galactosidase and transduction efficiency was quantified by cytochemistry and β‐galactosidase activity assay. Coxsackie‐adenovirus receptor (CAR) levels and Ad binding were evaluated by immunocytochemistry in M199‐ vs. MEM‐cultured AMCM.ResultsOur results demonstrated dramatic differences in efficiency of Ad‐mediated gene transfer in AMCM cultured in MEM (90 ± 8%) vs. M199 (5 ± 1.2%). This difference was specific to AMCM, and was not observed in a number of other cells including neonatal rat cardiomyocytes. The enhanced transduction in MEM was associated with increased levels of CAR and Ad binding in AMCM.ConclusionsCulture medium has a profound effect on the efficiency of Ad‐mediated gene transfer in AMCM, perhaps via differential effects on CAR expression. These findings have important implications for increasing numbers of studies that employ viral gene transfer in adult cardiomyocytes derived from mouse models of cardiac diseases. Copyright © 2003 John Wiley & Sons, Ltd.
Establishment of embryonic neuroepithelial cell lines exhibiting an epiplastic expression pattern of region specific markers
Authors: Nardelli Jeannette , Catala Martin , Charnay Patrick 
Published: August 2003

AbstractNeuroepithelial b2T cells were derived from the hindbrain and the spinal cord of mouse transgenic embryos, which expressed SV40 T antigen under the control of a Hoxb2 enhancer. Strikingly, b2T cell lines of either origin exhibit a very similar gene expression pattern, including markers of the hindbrain and the spinal cord, such as Hox genes, but not of more anterior cephalic regions. In addition, the broad expression pattern of b2T cells, probably linked to culture conditions, appeared to be appropriately modulated when the cells were reimplanted at different longitudinal levels into chick host embryos, suggesting that these cells are responsive to exogenous signalling mechanisms. Further support for these allegations was obtained by culturing b2T cells in defined medium and by assessing the expression of Krox20, an odd‐numbered rhombomere marker, which appeared to be modulated by a complex interplay between FGF, retinoic acid (RA), and noggin. With respect to these as yet unique properties, b2T cells constitute an original alternative tool to in vivo models for the analysis of molecular pathways involved in the patterning of the neural tube. © 2003 Wiley‐Liss, Inc.
Antiatherogenic properties of lipid minor constituents from seed oils
Authors: Karantonis Haralabos C , Zabetakis Ioannis , Nomikos Tzortzis , Demopoulos Constantinos A 
Published: August 2003

AbstractA number of lines of evidence suggest that seed oils exhibit a protective effect against atherogenesis. Most of the protective compounds are still unidentified. In this study, polar lipids of seed oil samples from sesame, corn and sunflower were successively fractionated by high‐performance liquid chromatography. Each isolated lipid compound was tested in vitro for its ability to inhibit platelet‐activating factor (PAF) and thrombin‐induced washed rabbit platelet aggregation or to cause platelet aggregation. A significant number of lipids that exerted the above biological activities were detected. The most biologically active compounds were subjected to biological, chemical and spectroscopic analyses, and their structural data are presented. These results give a different explanation for the antiatherogenic action that seed oils exert. Given that PAF plays a pivotal role in atherogenesis, the fact that these oils contain PAF antagonists suggests their high nutritional value. Copyright © 2003 Society of Chemical Industry
Nutritive value of chicken and potato mixtures for infant and preschool children feeding
Authors: Sotelo Angela , Perez Lourdes 
Published: August 2003

AbstractTwo chicken/potato protein mixtures (50:50 and 60:40) were prepared for use in formulas of high nutritive value and low cost for the diet of undernourished children and those with lactose intolerance. The proximate analysis and amino acid content of the raw materials and mixtures were determined and the chemical score (CS) was calculated. The proximate analysis and amino acid content of a commercial soybean formula were used as reference. The protein quality of the mixtures was evaluated by protein efficiency ratio (PER) and digestibility measurements. The protein content of cooked chicken and potato on a dry basis was 889 and 70 g kg−1 respectively and the carbohydrate content of potato was 762 g kg−1. Tryptophan was the limiting amino acid in chicken for infants according to the 1985 FAO pattern (CS = 76), but not for preschool children. Valine was limiting in potato for both infants and preschool children (CS = 56 and 88 respectively). Tryptophan was limiting in both 50:50 and 60:40 mixtures for infants; also the PER was higher in the 60:40 mixture and not significantly different from the control (casein), but both were different from the 50:50 mixture. Since both chicken and potato are available even for low‐income people, a formula prepared in the 60:40 ratio is of potential benefit for infants or preschool children who have lactose intolerance, mainly in developing countries. Copyright © 2003 Society of Chemical Industry
Analysing the freshness of intact rice grains by colour determination of peroxidase activity
Authors: Chen TF , Chen CL 
Published: August 2003

AbstractFreshness is an important palatability characteristic of rice grains. However, this characteristic deteriorates rapidly during dry storage. In the present study we have developed an indirect method to examine the freshness of rice grains harvested in different crop seasons or stored under conditions known to accelerate deterioration. Bulk samples of intact brown rice grains were soaked in dianisidine solution containing guaiacol and H2O2, and the optical absorbance of the incubation solution was determined colorimetrically. Alternatively, intact brown rice grains were incubated in a similar solution in the wells of a 96‐well microplate, with one grain per well, and the optical absorbance of the incubation solution was measured by a microplate reader. The results indicated that cultivar, storage duration and temperature significantly affected the activities of grain peroxidase. Marked differences in the development of purple colour in the incubation solutions and in vitro peroxidase activity were also found among the brown rice grains sampled in different seasons. The changes in colour of the incubation solutions measured by either of the above methods paralleled the changes in grain activity of peroxidase assayed using an in vitro method. The proposed method can differentiate brown rice grains harvested in different seasons. Moreover, this method, if combined with suitable statistical clustering procedures, can detect the blending status of fresh/old brown grains in a sample. The advantages of this test method using A385 over the conventional enzyme activity assay are the rapidity and simplicity with which A385 can estimate the in vitro determination of peroxidase activity of tested rice grains. Copyright © 2003 Society of Chemical Industry
Effects of roasting on ruminal nutrient degradability of sunflower seed
Authors: Sarrazin P , Mustafa AF , Chouinard PY , Raghavan GSV , Sotocinal SA 
Published: August 2003

AbstractA study was conducted to determine the effects of roasting sunflower seed using heated particulate medium (heated salt at 250 °C, 60 s contact of salt and sunflower seed and 120 s holding time) on crude protein (CP) fractions, ruminal dry matter (DM) and CP degradabilities, and ruminal disappearance of amino and fatty acids. Two ruminally fistulated cows were used in a randomised complete block design. Roasting of sunflower seed decreased (P < 0.05) soluble protein and increased (P < 0.05) neutral detergent‐insoluble protein with little effect on acid detergent‐insoluble protein. Results of the in situ nylon bag study showed that roasting decreased (P < 0.05) ruminal degradability of DM and CP and increased (P < 0.05) ruminal undegraded CP of sunflower seed. Roasting increased (P < 0.05) intestinal digestibility of ruminal undegraded protein. Ruminal disappearance of all amino acids (following 12 h of incubation) was greater (P < 0.05) for raw than for roasted sunflower seed. Similar results were also observed for ruminal disappearance of fatty acids. It was concluded that roasting of sunflower seed using heated salt decreased ruminal nutrient degradabilities and thus increased the concentrations of amino acids and polyunsaturated fatty acids available for digestion in the small intestine. Copyright © 2003 Society of Chemical Industry
Endoscopic laser imaging of tissue perfusion: New instrumentation and technique
Authors: Forrester K.R. , Stewart C. , Leonard C. , Tulip J. , Bray R.C. 
Published: August 2003

AbstractBackground and ObjectivesNew instrumentation, based on a previously established laser speckle perfusion imaging (LSI) technique is evaluated for its ability to capture and generate blood flow images during endoscopic surgery.Study Design/Materials and MethodsInvestigations are detailed in an in‐vitro blood flow model simulating physiological properties of vascularized tissue, and in‐vivo in rabbit joint capsule tissue.ResultsIn‐vitro measurements showed a linear response of the instrument to blood flow in the range of 0–800 μl/minute, where data points were significantly correlated with an r2 value of 0.96. In‐vivo measurements showed a 58.7% decrease to the medial collateral ligament during occlusion of the femoral artery.ConclusionsBlood flow images demonstrate that the endoscopic LSI technique is capable of measuring relative tissue blood flow changes at high resolutions and rapid response times and incorporates well with endoscopic surgeries. Lasers Surg. Med. 33:151–157, 2003. © 2003 Wiley‐Liss, Inc.