bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phenylalanine and its metabolites induce embryopathies in mouse embryos in culture
Authors: Denno Kelly M. , Sadler T. W. 
Published: June 2005

AbstractThe aim of this study was to determine the teratogenicity of phenylalanine (Phe) and Phe metabolites in neurulating mouse embryos. Therefore, the system of whole embryo culture was employed and D9 (neurulating) mouse embryos were exposed to Phe, phenylethylamine (PEA), phe‐nylpyruvic acid (PPA), phenylacetic acid (PAA), 2‐OH phenylacetic acid (2‐OH PAA), and phenyllactic acid (PLA) at concentrations ranging from 0.01 mM to 10 mM for 24 hours. After 24 hours, embryos were examined for morphological abnormalities and protein content by the Lowry method. Phe at 1 and 6 mM concentrations was not teratogenic; however, 10 mM inhibited cranial neural tube closure in 82% of the embryos. PEA was the most toxic factor and concentrations of 1 and 10 mM were embryo‐lethal, whereas neural tube closure defects (NTDs) were observed in 67% of the embryos at 0.1 mM. 2‐OH PAA was the second most toxic metabolite with concentrations of 1 and 10 mM producing NTDs in 10 and 100% of the embryos, respectively. PLA and PAA produced no NTDs at concentrations of 1 mM, 60% at 5 mM, and 100% at 10 mM. Finally, PPA produced approximately 50% NTDs at both 1 mM and 10 mM concentrations. PLA, PAA, 2‐OH PAA, and PPA produced a significant reduction in embryonic protein, and PEA and 2‐OH PAA reduced yolk sac protein values. PEA, 2‐OH PAA, PPA, PAA, and PLA also produced craniofacial abnormalities, i.e., incomplete expansion of the forebrain, collapse of the optic vesicle, and hypoplasia of the mandible and/or the maxilla. In summary, the results showed that the relative teratogenicity of Phe and its metabolites differs and suggested that a metabolite of Phe and/or a combination of Phe and one or more of its metabolites play a role in the phenylketonuric embryopathy.
Genetic control of the survival of murine trisomy 16 fetuses
Authors: Epstein Douglas J. , Vekemans Michel 
Published: June 2005

AbstractA mouse model that allows for the experimental induction of an aneuploid state has been employed to investigate the factors that factors that control the survival of trisomy 16 fetuses. The prevalence of trisomy 16 fetuses on day 15 of gestation was shown to vary significantly with the genetic background of the female parent. The ability to spontaneously abort a trisomy 16 conceptus was shown to be higher in the mouse strain with a low prevalence of trisomy 16, compared to those mouse strains with a high prevalence of trisomy 16. Furthermore, the maternal ability that selects against, or promotes the survival of a trisomic conceptus was shown to be specific for the trisomy in question.
Ultrastructure of murine trisomy 1 optic cup
Authors: Smith Barbara S. , Walker Nola J. 
Published: June 2005

AbstractThe optic cups of two gestational day 11 trisomy (ts) 1 mouse embryos and a normal littermate control were examined using transmission electron microscopy (TEM). One trisomic embryo had a small lens with a lens stalk; the other was aphakic. The resolution available with TEM allowed detailed evaluation of cell organelles, spatial relationships, and the intra‐ and extracellular structural environment of the optic cup in normal and abnormal mouse embryos. Differences between the normal littermate and the trisomic optic cups, as well as between the two ts 1 structures, included the following: (1) melanin granules in the retinal layer and intraretinal space as well as in the pigment layer, (2) neither pseudostratified nor cuboidal neuroepithelium in trisomic optic cups, (3) increasing cell lysis with severity of eye defect, (4) fusion between retinal and pigment layer cells and cells from the pigment layer and head mesoderm. This investigation not only confirmed some of the abnormal morphology found in light microscopic studies of ts 1 at this gestational age but also identified other anomalies in the ts 1 eye that may play a part in the dysgenesis of this organ. The roles of larger than normal intercellular lacunae, disorganized microtubules, and the connections between different cell types in the ts 1 optic cup require further investigation.
A critical review of the developmental toxicity and teratogenicity of 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin: Recent advances toward understanding the mechanism
Authors: Couture Laurie A. , Abbott Barbara D. , Birnbaum Linda S. 
Published: June 2005

AbstractA specific teratogenic response is elicited in the mouse as a result of exposure to 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD; dioxin). The characteristic spectrum of structural malformations induced in mice following exposure to TCDD and structurally related congeners is highly reproducible and includes both hydronephrosis and cleft palate. In addition, prenatal exposure to TCDD has been shown to induce thymic hypoplasia. These three abnormalities occur at doses well below those producing maternal or embryo/fetal toxicity and are thus among the most sensitive indicators of dioxin toxicity. In all other laboratory species tested, TCDD causes maternal and embryo/fetal toxicity but does not induce a significant increase in the incidence of structural abnormalities even at toxic dose levels. Developmental toxicity occurs in a similar dose range across species; however, mice are particularly susceptible to development of TCDD‐induced terata. Recent experiments using an organ culture were an attempt to address the issue of species and organ differences in sensitivity to TCDD. Human palatal shelves examined in this in vitro system were found to approximate the rat in terms of sensitivity for induction of cleft palate. Investigators have suggested that altered regulation of growth factors and their receptors may involve inappropriate proliferation and differentiation of target cells, ultimately producing TCDD‐induced terata. Why the teratogenic effects of TCDD are so highly species and tissue specific, and which animal species most accurately predicts the response of the human embryo/fetus, at the levels of exposure experienced by humans, still remains to be clarified.
Whole embryo culture, teratogenesis, and the estimation of teratologic risk
Authors: New D. A. T. 
Published: June 2005

AbstractMammalian whole‐embryo culture systems are now widely used and have proved useful in many studies of normal and abnormal development. The main advantages of these systems are that they allow precise control of experimental conditions and can often provide information unobtainable from in vivo studies; the main disadvantages are the rather short period of embryonic development that can be supported in culture and the present restriction of the techniques to very few species. The possibility of using whole‐embryo culture systems for screening for new teratogenic agents remains controversial, but there are indications that the systems may have more potential in this area than has sometimes been supposed.
Brain hemorrhages in cocaine‐exposed human fetuses
Authors: Kapur Raj P. , Shaw Cheng M. , Shepard Thomas H. 
Published: June 2005

AbstractAutopsies of 4 fetuses exposed to maternal cocaine are reported. Brain examination revealed hemorrhages in 3 of the fetuses involving the germinal matrix. The hemorrhages resembled subependymal germinal matrix hemorrhages seen as postnatal complications in premature infants with idiopathic respiratory distress syndrome. One of the placentas had sonographic evidence of abruption which could not be confirmed pathologically. The findings are discussed in light of reports of neurobehavioral deficits and other congenital anomalies in children and animals exposed to cocaine in utero. Speculations about the pathophysiologic events leading to these findings are made.
Ameltolide. II: Placental transfer of radiocarbon following the oral administration of a novel anticonvulsant in rats
Authors: Pohland Raymond C. , Vavrek M. Thaddeus 
Published: June 2005

AbstractThe placental transfer of orally administered ameltolide was evaluated to confirm embryonic exposure in the rat developmental toxicity study (Higdon et al., '91). Dissection techniques were used to determine the amount of total radiocarbon that traversed the placenta and distributed within the embryo in pregnant CD rats 0.75, 2, 5, 12, and 24 h after a single oral gavage dose of 50 mg/kg [14C]ameltolide on gestation day 12. Quantification of radiocarbon within placental and embryonic tissues and amniotic fluid was determined and compared with maternal plasma, liver, kidney, uterus, and ovary. Highest concentrations of radiocarbon occurred at 5 h postdose in all tissues sampled (maternal and embryonic) and then declined steadily over the 24‐h time course of the study. Maternal liver contained the highest concentrations of radiocarbon at all time points and peaked at 5.86% of dose at 5 h. Embryonic tissues accounted for less than 0.2% of the administered dose at all time points. Tissue‐to‐maternal plasma ratios indicated that maternal liver and kidney concentrations were higher than maternal plasma concentrations at all time points. Uterine and ovarian concentrations were approximately equal to maternal plasma concentrations at 5, 12, and 24 h postdose. Although placental, embryonic, and amniotic fluid tissue‐to‐maternal plasma ratios were ⩽ 1.0, ratios increased slightly throughout the time course of this study. Results from this study confirm embryonic exposure to radiocarbon associated with [14C]ameltolide and/or its metabolites in the rat developmental toxicity study, which has demonstrated the lack of observable teratogenic effects.
Patterns and trends of multiple congenital anomalies in birth defects surveillance systems
Authors: Khoury Muin J. , Waters Grady D. , Erickson J. David 
Published: June 2005

AbstractInfants with multiple congenital anomalies (MCA) can provide important clues in the detection of teratogenic agents. Definition, classification, and ascertainment of MCA vary, however. We present comparative epidemiologic data on MCA from two U.S. surveillance systems: the Metropolitan Atlanta Congenital Defects Program, which ascertains major birth defects during the first year of life, and the Birth Defects Monitoring Program, a nationwide system that relies on newborn hospital‐discharge diagnoses. This system has two components: the Commission on Public Hospitals Activities (CPHA) and the McDonnell Douglas Health Information System (MDHIS). Our analyses were based on over 600,000 births occurring in Atlanta, and over 5 million births occurring nationwide. Infants were classified as having MCA if they had two or more major defects from different categories (central nervous system, eye, orofacial, gastrointestinal, cardiovascular, genitourinary, and musculoskeletal). Additional analyses were also done on infants with three or more defects. Compared with the nationwide system, Atlanta showed 1) a much higher rate of MCA (16.2 per 10,000 births vs. 4.9 and 3.8 per 10,000 births in CPHA and MDHIS, respectively) and 2) a higher rate of MCA with chromosomal syndromes (2.0 per 10,000 births vs. 0.6 and 0.3 per 10,000 births in CPHA and MDHIS, respectively). Moreover, in Atlanta, the proportion of MCA with recorded chromosomal syndromes increased substantially during 20 years. These data point to differences in the ascertainment of MCAs in birth defects surveillance systems. More effort is needed to improve the ascertainment and comparability of MCA in surveillance systems, an important step toward better detection of human teratogens.
In vitro effects of glucose and growth factors on limb bud and mandibular arch chondrocytes maintained at various serum concentrations
Authors: Styrud Johan , Eriksson Ulf J. 
Published: June 2005

AbstractIn human and experimental diabetic pregnancy there is an increased risk of congenital malformation in the offspring. Some malformations involve growth retardation and altered chondrocyte differentiation, suggesting that a diabetic milieu may modify embryonic cell replication and the development of (pre)chondrocytes. The aim of the present work was to study the effects of a diabetes‐like environment in vitro on the growth and differentiation of rat chondrocytes in the presence of specific growth factors and different concentrations of serum. This was performed with a modified micromass culture system of embryonic (pre)chondrocytes from the limb bud and mandibular arch areas using medium supplemented with different glucose concentrations and with serum from diabetic rats. An elevated ambient glucose concentration inhibited the growth of mature chondrocytes in vitro, and this effect was diminished in a serum‐rich culture milieu. The (pre)chondrocytes exhibited a marked dependence on the serum level in the culture medium for optimal in vitro development. Diabetic rat serum had the lowest stimulatory capacity of the three different types tested (at similar glucose concentrations), suggesting a deficiency of growth‐stimulating factor(s) rather than the presence of inhibiting factor(s) in this type of serum. One of the deficient factor(s) in diabetic rat serum may be similar to IGF‐II, but a combined deficiency of several growth‐stimulating agents is likely to be present. Chondrocytes originating from the mandibular arch in general appeared more sensitive to MSA and IGF‐II than those from the limb buds. The present observations support the notion that while diabetes‐induced hyperglycemia in the conceptus contributes to severe growth retardation of the mandibular arch, additional factors also play a role.
Induction of tissue transglutaminase and apoptosis by retinoic acid in the limb bud
Authors: Jiang Heng , Kochhar D. M. 
Published: June 2005

AbstractMesenchymal cells in the limb buds of midgestation mouse embryos suffer prominent cell death upon exposure to retinoic acid (RA), an event likely associated with the micromelic and phocomelic anomalies of the resultant fetuses. It has been suggested, but not yet shown, that cells die by an active process termed apoptosis rather than by necrotic cytolysis. In certain cell types, investigators have previously observed a specific and early effect of RA on transcriptional activation of the gene for tissue transglutaminase (tTG), an enzyme suspected to play a role in apoptosis. We report here a distinct but transient increase in tTG activity which accompanied the initiation of cell death in the mesenchymal cells located in the central core of RA‐treated limb buds. We also ascertained microscopically that the cytological appearance of the affected cells was consistent with a characterization of the process of cell death as apoptosis. © 1992 Wiley‐Liss, Inc.
Exencephaly and hydrocephaly in mice with targeted modification of the Apolipoprotein B (Apob) gene
Authors: Homanics G. E. , Maeda N. , Traber M. G. , Kayden H. J. , Dehart D. B. , Sulik K. K. 
Published: June 2005

AbstractApolipoprotein B (apoB) is a key structural component of several lipoproteins. These lipoproteins transport cholesterol, lipids, and vitamin E in the circulation. Humans that produce truncated forms of apoB have low plasma concentrations of apoB, β‐lipoproteins, cholesterol, and often vitamin E. This condition has been modeled in mice by targeted modification of theapoBgene. Homozygous transgenic mice display all of the hallmarks of the human disorder. Unexpectedly, approximately 30% of the perinatal homozygotes are exencephalic and of those that have closed neural tubes, approximately 30% are hydrocephalic. The latter condition has also been noted in a relatively small proportion of the heterozygous mice. Vital staining of gestational day 9 (GD9) homozygous offspring has illustrated a striking pattern of excessive cell death involving the alar plate of the hindbrain. Histological and scanning electron microscopic analyses have confirmed this finding. We speculate that varying degrees of affect, as noted among GD 9 and 10 embryos, lead to the spectrum of malformations, including hydrocephaly, present in term fetuses. Analysis of vitamin E deficiency as a possible causative factor has illustrated that homozygous fetuses, indeed, show this deficiency. Amelioration of the defects through α‐tocopherol supplementation of the maternal diet has been explored. Further analyses of this transgenic mutant promise to provide significant information relative to the role of deficiency of vitamin E and other apoB dependent compounds in dysmorphogenesis. © 1995 Wiley‐Liss, Inc.
Removal, early hand rearing, and successful reintroduction of an orangutan (Pongo pygmaeus pygmaeus/x abelii) to her mother
Authors: Keiter Mary D. , Reichard Timothy , Simmons Jack 
Published: June 2005

AbstractA newborn orangutan was removed from her mother 55 h after birth because no nursing had been observed. She was hand reared in a nursery for 3 d and then successfully reintroduced to her mother. Several factors that may have contributed to the successful reintroduction are discussed.
Local adaptation, coadaptation, and population boundaries
Authors: Templeton Allan R. , Hemmer Helmut , Mace Georgina , Seal Ulysses S. , Shields William M. , Woodruff David S. 
Published: June 2005

AbstractCoadaptation can occur either because of local adaptation in a geographically widespread population and/or because of intrinsic adaptation to the state of other genes or chomosomes. In either event, hybridization between animals with differently coadapted gene or chromosomal complexes can result in a decrease in fertility, viability, etc. in the initial hybrids and especially in later generations. This is known as an outbreeding depression. Moreover, releasing animals not adapted to the local environment can seriously hamper the effectiveness of a reintroduction program, and hybridization can also destroy the local adaptation. Coadapted gene complexes are best detected through studies on natural populations because the adaptive nature of the complex is often only apparent in the natural environment. In the absence of information on natural populations (but ideally as a supplement), the presence of coadapted gene complexes and population boundaries can be detected through mating behavior, a pedigree analysis that can detect outbreeding depressions and distinguish them from inbreeding depressions, or genetic and karyotypic surveys. Once an outbreeding depression has been detected, it can be used to redefine the boundaries of the populations to be managed. Basically, the outbreeding depression is avoided by preventing hybridization between animals with the different coadapted complexes. In some cases, formal subspecific designations have been used to define the population boundaries. Unfortunately, many subspecific designations were made before population‐thinking influenced taxonomy. It is important to emphasize the need to undertake modern biological studies and to collect additional information useful for systematics. If modern biological studies indicate that the subspecies have little or no biological significance, it is best to treat the animals as a single population and disregard the subspecific designations.
Biology, husbandry, and veterinary care of captive Chinese pangolins (Manis pentadactyla)
Authors: Heath Martha E. , Vanderlip Sharon L. 
Published: June 2005

AbstractWe report observations on the biology, diet, husbandry, and veterinary care of four adult Chinese pangolins (Manis pentadactyla) maintained at the University of California, San Diego, for 1.5 years; and the births of two baby pangolins. Experience indicates that the minimum requirements for Chinese pangolins is an enclosure 10–12 m2, 26°C ambient temperature, a nest box with sand floor, and litter boxes placed in one or two corners of the enclosure for defecation and urination. A diet of two cans of cat food (Science Diet or ZuPreem), 6 tablespoons Esbilac, 2 tablespoons psyllium seed powder, and two raw egg yolks provide adequate nutrition for four pangolins for 1–2 days. Veterinary care should include a complete physical examination of integument and organ systems, determination of blood values, fecal analysis, and treatment with the anthelmintic thiabendazole for elimination of internal parasites. Parasites observed in the four pangolins included Strongyloides, hookworms, filarial nematodes (species unidentified), and nematodes of the genus Cylicospirura. The baby pangolins were born in November (male) and February (female), weighed 93 g and 92 g at birth, and lived 1 and 5 days, respectively. All adult pangolins observed strictly nocturnal behavior patterns.
Reproductive and hormonal changes during the estrous cycle and pregnancy in Asian elephants (Elephas maximus)
Authors: Mainka S. A. , Lothrop C. D. 
Published: June 2005

AbstractSerum progesterone and urinary total estrogen concentrations were determined weekly to bi‐weekly in 2 female Asian elephants for 96 weeks. The mean estrous interval was approximately 16 weeks in the nonpregnant animal. A total of 5 cycles were observed in the 96 week study period. The serum progesterone concentration ranged from 150 pg/ml to greater than 350 pg/ml during the luteal phase of the estrous cycle. The serum progesterone was elevated for 8–12 week weeks of the 16 week estrous cycle. The urinary total estrogen concentration ranged from less than 10 to greater than 300 pg/μg creatinine. The second animal was pregnant at the beginning of the study period. The serum progesterone concentration was elevated (> 100 pg/ml) in the pregnant animal until parturition. The urinary total estrogens increased from approximately 50 pg/μg creatinine to greater than 400 pg/μg creatinine during the first year of pregnancy and remained elevated until parturition. Estrous cycling had not resumed by 3 months post partum.
EFFECT OF TREATMENT OF STARCHY WATER ON QUALITY OF PASTA DURING CONTINUOUS COOKING
Authors: KORZENIOWSKA JOLANTA , KORZENIOWSKI DARIUSZ , DEFRANCISCI LEONARD , HOSKINS DONALD F. 
Published: June 2005

ABSTRACT Industrial continuous pasta cookers are filled with thousands of liters of cooking water. During the cooking process, the starch leaches from the cooked pasta. As the starch concentration increases, the cooked pasta becomes less firm and stickier. Starchy water must be constantly released to reduce the starch concentration. This requires addition of fresh makeup water and energy used to reheat it. The effects of presteaming freshly extruded pasta and posttreatment at high temperature and pressure of the starchy cooking water on the pasta cooking quality was tested. The posttreatment consisted of elevating the water temperature to 120C and the pressure to 1.0297 × 10

5
Pa. The viscosity of cooking water decreased from 1.039 × 10−5 m2/s to 7.280 × 10−6 m2/s as a result of the temperature degradation of amylose. Applying high pressure/temperature treatment to the cooking water, as well as straining it through a tight mesh screen, makes it possible to use the same cooking water for a longer period of time. This, in turn, reduces the wastewater produced in continuous cookers, without decreasing the quality of cooked pasta. This results in the conservation of the water and energy.
UPTAKE OF SUCROSE SOLUTION BY EXTRUDED CORN BALLS AND EFFECT ON THE TEXTURAL CHARACTERISTICS
Authors: AGARWAL KALPESH , BHATTACHARYA SUVENDU 
Published: June 2005

ABSTRACT Extruded corn balls were subjected to dip coating with sucrose solutions (0–70%) at different temperatures (20–50C) to determine several coating characteristics such as total uptake, uptake of solid and dimensionless uptake (sucrose solution uptake/water uptake). Textures of the wet sample, as well as the dried sample, were determined under compressive loading, to obtain the maximum force offered and the deformability modulus. A progressive increase in solid uptake occurs with an increase in concentration and/or temperature while the effect of the latter is low. The deformability modulus of the samples drastically increases because of the absorption of sucrose and because of drying. The desirable high dimensionless uptake can be obtained with a high concentration of sucrose at a low temperature. The uptake of solid generally shows a significant relationship (P ≤ 0.05) with other coating and textural parameters for the wet sample, but not with the dry product.