bluuebunny/crossref_metadata_2025 huggingface dataset:
Selenium kinetics, placental transfer, and neonatal exposure in cynomolgus macaques (Macaca fascicularis)
Authors: Hawkes Wayne Chris , Willhite Calvin C. , Omaye Stanley T. , Cox Douglas N. , Choy Wai Nang , Tarantal Alice F.
Published: June 2005

Forty pregnant cynomolgus macaques were treated daily from gestational day 20 to 50 by nasogastric intubation of 0, 25, 150, or 300 μg selenium asL‐selenomethionine/kg body weight. In each group, 7–8 pregnancies were terminated by hysterotomy at gestational day 100 ± 2 and the fetuses were examined, while 2–3 pregnancies in each group were allowed to proceed to term. Selenium and soluble glutathione peroxidase were measured in: maternal, neonatal, and fetal plasma and erythrocytes; fetal kidney, liver, muscle, and placenta; and maternal breast milk. The area under the multidose maternal plasma selenium concentration:time curve, the maximum maternal plasma selenium concentration, and the maternal urinary selenium excertion rates were proportional to theL‐selenomethionine dose. Selenium concentrations in all fetal and neonatal tissues were also proportional to maternalL‐selenomethionine dose. Glutathione peroxidase was affected only in maternal erthrocytes, fetal kidney, and neonatal plasma. The selenium concentration in fetal plasma was an average 33% of that in maternal plasma. Although selenium concentration in macaque milk were doubled by the highest does, intrauterine selenium accumulation accounted for the majority of the neonatal selenium body burden. Despite the elevated selenium concentrations in fetal tissues, neonatal blood, and milk, no deleterious effects on neonates were observed. There results suggest that primate fetuses are well protected against selenium toxicity arising from high maternalL‐selenomethionine intakes. © 1994 Wiley‐Liss, Inc.
Placental teratoma with three‐germ layer differentiation
Authors: Sironi Maria , Declich Paolo , Isimbaldi Giuseppe , Monguzzi Alberto , Poggi Giuseppe
Published: June 2005

A rare case of placental teratoma is described. Major features were the presentation as a pedunculated mass from the fetal surface of the placenta, the mixture of different tissues derived from all three germ layers (skin with dermal appendages, ganglion‐like cells, and nervous structures, gut structures, osteocartilagineous and smooth and striated muscle), and the absence of segmental organization. © 1994 Wiley‐Liss, Inc. © 1994 Wiley‐Liss, Inc.
In vitro embryotoxicity of the cysteine proteinase inhibitors benzyloxycarbonyl‐phenylalanine‐alanine‐diazomethane (Z‐Phe‐Ala‐CHN2) and benzyloxycarbony1‐phenylalanine‐phenylalanine‐diazomethane (Z‐Phe‐Phe‐CHN2)
Authors: Ambroso Jeffrey L. , Harris Craig
Published: June 2005

This study makes use of whole embryo culture to investigate the potential embryotoxicity of benzyloxycarbonyl‐phenylalanine‐alanine‐diazomethane (Z‐Phe‐Ala‐CHN2) and benzyloxycarbonyl‐phenylalanine‐phenylalanine‐diazomethane (Z‐Phe‐Phe‐CHN2), two low molecular weight, active site‐directed and irreversible inhibitors of the lysosomal cysteine proteinases. Peptidyl diazomethanes are the most specific inhibitors available for lysosomal cysteine proteinases and can be hypothesized to interrupt visceral yolk sac (VYS)‐mediated nutrition during early organogenesis. When added directly to the culture medium of gestational day 10–11 rat conceptuses, both compounds inhibited lysosomal cysteine proteinase activity in the VYS in a concentration‐dependent fashion that correlated with the degree of embryotoxicity observed. Z‐Phe‐Ala‐CHN2 and Z‐Phe‐Phe‐CHN2 were also found to increase the protein content of the VYS, even though all other conceptal growth parameters decreased. This effect was dependent on the serum content of the culture medium and the exposure time. Histological examination of Z‐Phe‐Ala‐CHN2‐treated conceptuses revealed a dramatic increase in the size and number of vacuoles in the VYS endoderm epithelium, suggestive of inhibition of VYS proteolysis. At the same time, excessive cell death was observed throughout the neuroepithelium and in specific regions of the mesenchyme of the corresponding embryos. This cell death manifested morphological characteristics of apoptosis and could be detected by supravital staining with Nile Blue Sulphate. These findings provide additional evidence in support of the hypothesis that lysosomal cysteine proteinases play a critical role in VYS‐mediated histiotrophic nutrition and suggest that peptidyl diazomethanes may be useful in further characterization of these enzymes. The possible direct effects of these inhibitors on embryonic cells and the relationships between interruption of VYS‐mediated nutritional processes and embryonic cell death are discussed. © 1994 Wiley‐Liss, Inc.
Cell death and cell cycle perturbation in the developmental toxicity of the demethylating agent, 5‐Aza‐2′‐deoxycytidine
Authors: Rogers John M. , Francis B. Magnus , Sulik Kathleen K. , Alles Ajit J. , Massaro Edward J. , Zucker Robert M. , Elstein Kenneth H. , Rosen Mitchell B. , Chernoff Neil
Published: June 2005

DNA methylation is a probable mechanism for regulating gene expression, and alterations in methylation may significantly affect embryonic development. We administered the cytidine analogue 5‐aza‐2′‐deoxycytidine (dAZA), a specific and potent demethylator of DNA, to pregnant mice to determine its teratogenicity and effects on embryonic cell death and cell cycle. Groups of females were dosed intraperitoneally on gestation day 10 with doses of 0.05‐3 mg/kg dAZA and killed at 4, 8, or 28 hr later. Two embryos per litter were immediately stained with Nile blue sulfate (NBS) to identify areas of cell death; the remaining embryos were frozen and stored for subsequent flow cytometric (FCM) analysis of the cellular DNA synthetic cycle in limb buds. A dose‐related accumulation of cells in the S and G2/M phases was observed at 4 and 8 hr after maternal dosing. S‐phase accumulation was the most sensitive indicator of effect; a dose‐related increase in the percentage of hindlimb bud cells in S‐phase was evident at all dosages 4 hr after maternal dosing. By 28 hr postdosing, a normal cell cycle phase distribution was observed at doses of < 0.3 mg/kg. However, cell cycle perturbations persisted at higher dosages. NBS staining demonstrated increased cell death in areas of rapid cell division, indicative of replication‐associated cytotoxicity, at doses of ≥0.1 mg/kg. Observation of litters from additional dams killed at term revealed that at dosages of ≥0.3 mg/kg, cleft palate and hindlimb defects were significantly elevated. In addition, above 0.3 mg/kg, fetal weight was significantly decreased. Embryonic mortality did not increase significantly at dosages of < 2 mg/kg but reached 100% at 3 mg/kg. Vertebral and pelvic girdle malformations were seen at doses of 2l mg/kg. These results indicate that the demethylating agent dAZA perturbs embryonal DNA synthesis and results in the death of rapidly proliferating cells. The observation of cell cycle perturbations and cell death at dosages below those producing frank terata indicate some ability of the embryo to compensate for and/or repair dAZA‐induced cellular damage. © 1994 Wiley‐Liss, Inc.

This article is a US Government work and, as such, is in the public domain in the United States of America.
Maternal restraint stress‐enhanced teratogenicity of all‐trans‐retinoic acid in CD‐1 mice
Authors: Rasco Jane F. , Hood Ronald D.
Published: June 2005

The present study combined maternal restraint stress with a teratogenic agent, all‐trans‐retinoic acid (†RA). Five treatment groups were used initially: (1) vehicle (corn oil) control [C],(2) food/water‐deprived [FWD], (3) †RA only [†RA](4)restraint only [R], and (5) †RA plus restraint [†RA+R] Mated CD‐1 mice in groups 3 and 5 were given 20 mg/kg †RA po. Mice in groups 4 and 5 were restrained in the supine position for 12 hr (9:00 a.m. to 9.00 p.m.), and the FWD group mice were deprived during the same time period. The †RA+R mice were dosed immediately prior to the 12‐hr restraint period. All treatments were administered on gestation day (GD) 9 (copulation plug = day 1). On GD 18, all females were killed and subjected to teratological examination. The incidences of resorptions, short tails, bent tails, fused ribs, and fused vertebrae were significantly increased in the †RA+R group, in comparison with all other groups. Spina bifida was observed only in the †RA+R group. The current results, combined with those of earlier studies with other agents, support the likelihood that maternal stress can exacerbate adverse effects of chemical teratogens on mouse development.
Reduced recurrence of orofacial clefts after periconceptional supplementation with high‐dose folic acid and multivitamins
Authors: Tolarova Marie , Harris John
Published: June 2005

To assess effects of periconceptional multivitamin and folic‐acid supplementation on recurrence of cleft lip with or without cleft palate (CL±P), we prospectively evaluated 221 pregnancies in women at risk of a child with CL±P. The 10‐step protocol included multivitamin supplementation with SPOFAVIT (A, B1, B2, B6, C, D3, E, nicotinamide, calcium pantothenicum) and folic acid (10 mg/day), beginning ≥2 months before planned conception and continuing for ≥3 months thereafter. A comparison group comprised 1,901 women at risk of a child with CL±P, who received no supplementation and gave birth within the same period as the study group. In the supplemented group, 3 of 214 informative pregnancies ended with infants with CL±P, a 65.4% decrease (observed versus expected value ‐5.67; P = 0.031, Fisher's exact test); the expected value of 8.7 was calculated based on the incidence of cleft among first‐degree relatives among the comparison group. Subset analysis by proband's sex, severity of CL±P, and both variables showed highest supplementation efficacy in probands with unilateral cleft (82.6% decrease, P = 0.024, Fisher's exact test). No efficacy was observed for female probands with bilateral CL±P. Generally, efficacy was greater for subgroups with unilateral than with bilateral cleft and for male than female probands. These findings confirm the need for a randomized, double‐blind, controlled multicenter trial to establish whether periconceptional vitamin supplementation, prevent CL±P and, if it does, whether the effective agent is folic acid or multivitamins, or both combined. © 1995 Wiley‐Liss, Inc.
Developmental toxicity of formate and formic acid in whole embryo culture: A comparative study with mouse and rat embryos
Authors: Andrews James E. , Ebron‐McCoy Marian , Kavlock Robert J. , Rogers John M.
Published: June 2005

Acute methanol (MeOH) toxicity in primates is attribute to the conversion of MeOH to formate and the resulting acidosis. MeOH has been shown to be developmentally toxic in mice and rats both in vivo and in vivo, but rodents neither accumulate formate nor develop acidosis after MeOH exposure. To further assess the potential human developmental effects of sodium (Na) formate and formic acid in rodent whole embryos were cultured (WEC). Day 9 rat embryos were cultured for 24 or 48 hours and day 8 mouse embyos were cultured for 24 hours in the presence of Na‐formate or formic acid. Rat and mouse embryos exposed to either agent for 24 hours exhibited a trend toward reduced growth and development and the number of abnormalities increased at the higher concentrations. Rat embryos exposed for 48 hours to either Na‐formate or formic acid showed a trend toward reduced growth and development with increasing concentrations. The anomalies abserved in both species after exposure to either compound were primarily open anterior and posterior neuropore with less frequent incidence of rotational defects, tail anomalies, enlarged pericardium and delayed heart development. Exposure to Na‐formate or formic acid for comparable periods of time results in comparable degrees of embryotoxicity at concentrations (mMolar) at least 4‐fold lower than those previously reported for methanol exposure. © 1995 Wiley‐Liss, Inc.

This article is a US Government work and, as such, is in the public domain in the United States of America.
Antisense targeting of Engrailed‐1 causes abnormal axis formation in mouse embryos
Authors: Sadler T. W. , Liu Edison T. , Augustine Karen A.
Published: June 2005

Antisense oligonucleotide targeting ofengrailed‐1 (En‐1) in early somite mouse embryos resulted in reducedEnprotein levels and produced abnormalities of the brain, face, and heart and shortening of the embryonic axis (caudal dysgenesis). Defects of the brain and limbs were consistent with abnormalities observed in null mutant mice described by other investigators. Abnormalities of the face and heart may be related to alterations in neural crest cells. Caudal dysgenesis suggested a role forEn‐1in axis formation and this hypothesis was supported by results showing thatEn‐1 protein and mRNA are present in the primitive streak. Thus, in addition to participating in the signaling pathway for brain and limb development, En‐1 appears to play a role in patterning the embryonic axis. © 1995 Wiley‐Liss, Inc.
Platelet‐derived growth factor receptor alpha subunit deleted Patch mouse exhibits severe cardiovascular dysmorphogenesis
Authors: Schatteman Gina C. , Motley S. Tim , Effmann Eric L. , Bowen‐Pope Daniel F.
Published: June 2005

Path (Ph) mice, whose platelet‐derived growth factor receptor alpha subunit (αPDGFR) gene has been deleted, have been used to elucidate requirements for αPDGFR for normal murine development. In this report we evaluate the role of αPDGFR in cardiovascular development by using in situ hybridization to follow the changing pattern of αPDGFR expression in cardiovascular tissues after embryonic day 13, and comparing this pattern with the pattern of cardiovascular defects observed in homozygous Ph mutants. Both mesodermally derived and neural crest‐derived components of the cardiovascular system are severely dysmorphic in Ph/Ph embryos and those structures most severely affected are those that normally express αPDGFR mRNA at the highest levels and for the longest duration. Ph/Ph vessels appear to be lined with a normal endothelium, but contain a reduced number of smooth muscle cells and are fragile during processing for histology. The myocardium is thin, the heart is small and dysmorphic, the valves are malformed, and the interventricular and interatrial septa of the heart are defective. In the outflow tract, the spectrum of defects includes both persistent truncus arteriosus and double outlet right ventricle. This pattern of abnormalities is consistent with the hypothesis that deletion of αPDGFR results in a functional ablation of cranial neural crest cells, and that mesodermally derived components of the vascular system also require αPDGFR. © 1995 Wiley‐Liss, Inc.
Programmed cell death and N‐acetoxy‐2‐acetylaminofluorene‐induced apoptosis in the rat embryo
Authors: Thayer Jeanette M. , Mirkes Philip E.
Published: June 2005

N‐acetoxy‐2‐acetlylaminofluorene(N‐Ac‐AAF) is an alkylating agent that forms DNA adducts at C‐8 is guanine and causes single strand breaks. It has abnormal development have not been investigated. Previous studies have indicated that other DNA alkylating agents cause cell death during embryonic development although the types of cell death were not characterized. Using a whole embryo culture system, gestation day 10 rat embryo were exposed to several concentrations (5, 50 and 200 μg/ml)of N‐Ac‐AAF at several times points after expire was begun (5,10,24 hours), the embryos were removed from culture from culture and examined to identify location, type and quantity of cell death, relative to programmed cell death observed in control embryos. Vital staining with Nile blue sulphate revealed that the location of N‐Ac‐AAf‐ include cell death included the forebrain region, tail and areas of programmed cell death Examination of tissue section from both control and treated embryos indicated that the location of apoptotic cell death revealed by in situ DNA nick end ‐labelling was generally consistent with the cell death pattern observed by vital staining of whole embryos. Agarose gel analyses indicated that all concentration of N‐Ac‐AAF caused DNA fragmentation, and Quantification demonstrated a dose response. Examination of treated embryos (50 and 200μg/ ml) by transmission electron microscopy revealed that, by 5 hours after exposure, cells with class, ultrastructural features of apoptosis were present. In conclusion, multiple method have all indicated that, regardless of exposure level, apoptosis was the predominant from of cell death. Because opotosis also occurs in developmental cell death, it is possible that apotosis induced by N‐Ac‐AAF is due to an alternation in cell fate via premature or ectopic induced of the cell death program. © 1995 Wiley‐Liss, Inc.
Utility of fluorescence microscopy in embryonic/fetal topographical analysis
Authors: Zucker Robert M. , Elstein Kenneth H. , Shuey Dana L. , Ebron‐Mccoy Marian , Rogers John M.
Published: June 2005

For topographical analysis of developing embryos, investigators typically rely on scanning electron microcopy (SEM) to provide the surface details not attainable with light microscopySEM is an expensive and time consuming technique, however, and the preparation procedure may alter morphology and leave the specimen friable. We report that by using a high‐resolution compound epilfluorescence microscope with inexpensive low‐power objectives and the flurochrome acridine orange, we were able to obtain surface image of fixed or fresh whole rat embryos and fetal palates of considerably greater topographical detail than those obtained using routine light microscopy. Indeed the resulting high‐resolution image offered not only superior qualitative documentation of morphological observation, but the capability for detailed morphometry via digitization and computer‐assisted image analysis. © 1995 Wiley‐Liss, Inc.
Induction of apoptosis and cathepsin D in limbs exposed in vitro to an activated analog of cyclophosphamide
Authors: Moallem S. Adel , Hales Barbara F.
Published: June 2005

Apoptosis, a form of active cell death, plays a role during normal limb development. The present study was done to test the hypothesis that the teratogen cyclophosphamide, an alkylating agent and commonly used anticancer drug, produces malformations by disturbing the regulation of apoptosis in the limb. The effects of a preactivated analog of cyclophosphamide, 4‐hydroperoxycyclophosphamide, on limb development and on apoptosis in the limb were determined in vitro. Cathepsin D is a lysosomal protease which is induced in tissues undergoing destruction by apoptosis. To further examine the process of apoptosis in the limb, the effects of 4‐hydroperoxycylophosphamide exposure on cathepsin D protein concentration and on the immunolocalization of cathepsin D in limb buds were assessed. Limb buds from gestational day 12 mice were excised and cultured in roller bottles in a chemically defined medium for up to 6 days. The addition of 4‐hydroperoxycyclophosphamide (1 or 10 μg/ml) to the culture medium produced time‐ and concentration‐dependent limb malformations. Electrophoresis of the DNA extracted from both control and treated limbs revealed a DNA fragmentation pattern characteristic of apoptosis. Limbs cultured in the control medium showed a “DNA ladder” only after 72 hours in vitro; however, those in the drug‐treated groups showed fragmentation within 12 hours of drug exposure. Acridine orange staining and examination of cell ultrastructure with the electron microscope further confirmed that apoptotic cell death in the interdigital areas was accelerated in drug‐exposed limbs. The relative abundance of cathepsin D in limbs exposed to 4‐hydroperoxycyclophosphamide for 24 hours was increased compared to control limbs. Using immunohistochemical staining at the light microscope level, the cathepsin D protein in control limbs was localized mainly to the interdigital and apical ectodermal ridge areas; staining in these areas was increased in limbs exposed to 4‐hydroperoxycyclophosphamide. Using immunogold electron microscopy, cathepsin D immunoreactivity was found to be localized in phagocytosed apoptotic bodies; this observation suggests that it is the process of phagocytosis which induces cathepsin D. Thus, exposure to 4‐hydroperoxycylophosphamide increased apoptosis in the interdigital areas and apical ectodermal ridge of mouse limb buds in vitro. Moreover, cathepsin D may play an important role in mediating the phagocytosis of apoptotic bodies in the teratogen‐exposed limbs. ©1995 Wiley‐Liss, Inc.
Descriptive epidemiology of alimentary tract atresia
Authors: Harris John , Källén Bengt , Robert Elisabeth
Published: June 2005

A study has been made on certain epidemiological characteristics of infants with alimentary tract atresia: esophageal atresia, small and large gut atresia, and anal atresia. Data were collected from three malformation registries and represent a material of more than 4.5 million births. A total of 3,550 infants with alimentary atresia were identified corresponding to a total rate of about 8 per 10,000 births. In 167 infants (4.7%) more than one of the major atresia types were present simultaneously. Racial differences were found (based on data from California) for esophageal atresia where whites had a higher rate than other races. For gastrointestinal atresia, a high rate in blacks was found, while no differences between races were seen for anal atresia. Also, differences in registered rates between the three programs were found, at least partly explainable by different ascertainment. The different forms of atresia were compared from the point of view of sex ratio, twinning rate, maternal age and parity distribution, presence of chromosome anomalies, and types of associated malformations. The pathogenesis and etiology of the various types of atresia are discussed based on these observations. The conclusion is that although undoubtedly other pathogenetic mechanisms may exist for gastrointestinal atresia, a substantial proportion of all infants with alimentary atresia had their malformations as a result of early disturbances of intestinal morphogenesis. Within each subgroup, apparently different etiologies may exist, resulting in differences in epidemiological characteristics. © 1995 Wiley‐Liss, Inc.
Incomplete development of the spleen and the deformity in the chimeras between asplenic mutant (Dominant hemimelia) and normal mice
Authors: Suto Jun‐Ichi , Wakayama Teruhiko , Imamura Kenkichi , Goto Saori , Fukuta Katsuhiro
Published: June 2005

The semidominant gene Dh (Dominant hemimelia) induces skeletal and visceral abnormalities of various degrees and failure of the spleen in mice. The homozygous individual (Dh/Dh) seems to be lethal. The present experiment was designed to investigate the ability Dh cells to form a spleen and the genesis of the hind limb malformations by Dh/Dh and Dh/+ cells in chimeric mice. The Dh/Dh and Dh/+ embryos were produced in the F2 progeny of a cross between inbred strains of Dh/+ and DDD mice. They were aggregated with C3H/He or C57BL/6 embryos to make chimeras. Identification of Dh/Dh or Dh/+ embryos was carried out by Pep‐3, and chimerism was analyzed by Gpi‐1. Of 25 chimeras carrying the Dh gene, four mice formed a small spleen, two mice had a vestigial spleen, and the others no spleen. The tissues of the incompletely developed spleens were normal histologically and Dh cells were involved in the tissues of the spleen. In the chimeric mice, hindlimb malformation by the Dh gene was reduced in severity and the lethality of the homozygote (Dh/Dh) was rescued. © 1995 Wiley‐Liss, Inc.
Effects of chloroquine and its enantiomers on the development of rat embryos in vitro
Authors: Tagoe Clifford N. B. , Ofori‐Adjei David
Published: June 2005

The effects of the antimalarial drug chloroquine (CQ) and its enantiomers [(+)]‐CQ and (−)‐CQ on 9½‐day post‐implantation rat conceptuses were studied by the whole‐embryo culture technique over a 48 hr period. At a concentration of 500ng/ml of culture medium (0.97 μM), which falls within serum levels attained during long‐term CQ therapy, the drugs produced varying degrees of growth retardation and dysmorphogenesis in the conceptuses. These effects were most severe with exposure to racemic CQ (100%) and also to equimolar concentrations of the two enantiomers (90%). Dysmorphogenesis was least with (+)‐CQ (30%) and intermediate in severity in those exposed to (−)‐CQ (32%). In the CQ and combined enantiomer groups, there was significant reduction in yolk sac diameter to 81% and 73%, the crown‐rump length to 77% and 71%, the number of somites to 76% and 74%, and the embryonic protein content to 64% and 49%, respectively, of control values. In the (−)‐enantiomer group the only parameter significantly affected was the somite number which was reduced to 83% of control. The growth parameters of (+)‐CQ‐ treated embryos did not differ significantly from controls. The commonest morphological abnormalities observed in all treatment groups were those of axial rotation. Unfused and underdeveloped cranial neural tube, microophthalmia and abnormal otic primordium also occurred frequently, especially in the CQ and enantiomeric combination groups. The results suggest that the commercially available form of chloroquine, CQ, is embryotoxic in doses comparable to serum levels reached during long‐term therapy with the drug. It also appears that although the individual enantiomers show minimal embryotoxicity at the dosage used, they potentiate each other's effects in the racemic mixture. © 1995 Wiley‐Liss, Inc.
Comparative disposition, receptor affinity, and teratogenic activity of sulfon arotinoids
Authors: Willhite Calvin C. , Dubois Antoine , Schindler‐Horvat Janice , Apfel Christian , Eckhoff Christian
Published: June 2005

To investigate the relationship between sulfon arotinoid biotransformation and teratogenic activity, the potency of the ethyl (Ro 15‐1570) and methyl (Ro 14‐9706) arotinoid sulfones and their in vivo disposition in pregnant hamsters were studied. Administration of Ro 15‐1570 was teratogenic, but Ro 14‐9706 showed no such activity. Total absorbed doses of the ethyl and methyl sulfones (measured as maternal plasma AUC) were very similar. Total delivered dose of Ro 14‐9706 to liver and lung was 120–160% that of Ro 15‐1570, and Ro 14‐9706 was transferred in greater amounts to the embryo as well. Placenta AUC for parent sulfon arotinoids was 160–250% that in the embryo. Plasma analyses by HPLC suggested that the ethyl sulfone was oxidized and appeared in maternal plasma as the corresponding sulfinic (Ro 14‐9572) and sulfonic (Ro 14‐3899) acids, amounting to 10% and 16%, respectively, of the mean maternal ethyl sulfone Cmax value. The concentrations of sulfinic and sulfonic metabolites were always less than the analytical limit of detection in placenta and embryo after maternal ethyl sulfone intubation. Neither the sulfinic nor the sulfonic acid were ever detected in maternal circulation, placenta, or embryo after methyl sulfone intubation. Comparisons of their binding affinities found that neither the ethyl nor the methyl arotinoid sulfone could act as a ligand for cellular retinoic acid‐binding protein (CRABP), nor could these compounds bind retinoid nuclear receptors (RAR). Transcriptional activation of RARs was weak and similar for both compounds. The sulfinic and sulfonic acid arotinoids bind and transactivate RARs, and bind CRABP with efficiencies similar to all‐trans‐retinoic acid. Furthermore, they are active in cultured limb bud chondrocytes. The results suggest that the methyl sulfone (in accord with its lack of activity in cultured limb bud chondrocytes) is of no toxicologic significance in hamster embryo‐even after relatively high delivered dose. Teratogenicity of the ethyl sulfone (which shows marked inhibition of chondrogenesis in cultured limb bud) does not appear to depend on measurable concentrations of these sulfinic/sulfonic acid metabolites in the hamster embryo. © 1995 Wiley‐Liss, Inc.
Formation of protein–glutathione mixed disulfides in the developing rat conceptus following diamide treatment in vitro
Authors: Hiranruengchok Roongrudee , Harris Craig
Published: June 2005

Protein‐glutathione mixed disulfide (protein‐S‐SG) formation was investigated in developing rat conceptuses during early organogenesis (gestational day 10, GD 10) using the whole embryo culture system. Low levels of protein‐S‐SG (25.0±6.6 pmoles resolved GSH/conceptus) were found in conceptuses under normal culture conditions. Incubation of the conceptuses with 75‐500 μM diamide (a thiol oxidant) resulted in rapid increases in protein‐S‐SG (to 2‐ to 16‐ fold that of control values) in a dose‐dependent manner during 30 min of the culture period. Approximately 20% of the observed cytosolic glutathione (GSH) depletion following diamide (500 μM) could be accounted for as mixed disulfides of protein sulfhydryls, when determined in whole conceptual tissues after 15 min. The most extensive S‐thiolation of protein sulfhydryls by GSH was observed in visceral yolk sac (VYS) when compared to embryo proper and ectoplacental cone. This result indicates that the most abundant, sensitive, or accessible protein sulfhydryls were found in the VYS. Inhibition of glutathione disulfide reductase activity by pretreatment of the conceptuses with 25 μM BCUN for 2 hr potentiated protein‐S‐SG formation elicited by 75 μM diamide. Reincubation of the conceptuses in fresh media, following the 15‐min treatment with 500 μM diamide, reversed both the GSH depletion and the protein‐S‐SG formation in conceptal tissues. The reduction of the protein‐S‐SG was dependent on adequate intracellular GSH levels and was inhibited when GSH was rapidly depleted by subsequent addition of N‐ethylmaleimide (NEM, 100 μM). Under the same experimental conditions, addition of 1 mM dithiothreitol (DTT) did not significantly enhance the GSH restoration rate nor the protein‐S‐SG reduction rate. The results also indicated that low levels of intracellular cysteine do not play an important role in the reduction of protein‐S‐SG. Protein‐S‐SG formation may be important for cellular regulation and in mediating the embryotoxicity elicited by diamide or other oxidative stresses. © 1995 Wiley‐Liss, Inc.
Phenytoin causes phalangeal hypoplasia in the rabbit fetus at clinically relevant free plasma concentrations
Authors: Danielsson Bengt R. , Danielson Kiki , Tomson Torbjörn
Published: June 2005

New Zealand White robbits were treated orally with 0 (controls), 50, 100, or 150 mg/kg phenytoin on days 14‐16 of pregnacy. Total and free plasma concentrations of phenytoin were determined in maternal plasma 2, 6, and 24 hr after the final dose in all aimals. In addition, after administration of 150 mg/kg maternal plasma concentrations were also determined after 12 and 48 hr, the concentrations in amniotic fluid after 6 hr and those in fetal tissue 6 and 24 hr after the final treatment. A high degree of plasma protein binding was observed in maternal blood. Treatment with 50 mg/kg resulted in free plasma concentrations of up to 5.0 μmol/1 during the 24 hr period following the final dose. Significantly higher free plasma concentrations were observed at the two higher dose levels; up to 9.7 μmol/1 at 100 mg/kg and 12.7 μmol/1 at 150 mg/kg. Digital hypoplasia was not seen in the control group or the animals treated with 50 mg/kg. However, treatment with 100 mg/kg resulted in hypoplasia in a single or a few digits in approximately 50% of the fetuses, and 150 mg/kg provoked hypoplasia in almost all digits in all fetuses. These results show that even though the doses which caused digital defects in rabbits are much higher than those used therapeutically, the resulting free concentrations of phenytoin are similar to those which are associated wth the some type of defects in humans. These data indicate that the pharmacologically induced fetal hypoxia/ischemia and vascular disruption preceding malformations of this type, which were observed in a previous study in rabbits, may be of human relevance. © 1995 Wiley‐Liss, Inc.
Glycoconjugates in normal and abnormal secondary neurulation
Authors: Griffith C. May , Hsieh Tauyee , Smith Catherine , Sanders Esmond J.
Published: June 2005

In chick embrayos, the anterior greater portion of the neural tube develops by the folding, apposition, and fusion of the neuroectoderm. The smaller caudal portion that forms the secondary neural tube (lumbosacral and coccygeal regions) is derived from the tail bud, an aggregate of mesenchymal cells located at the caudal limit of the body. Tail bud mesenchyme, arranged in a solid cord, undergoes mesenchymal‐ epithelial transformation to form the secondary neural tube. Previous evidence suggests that this transformation is accompanied by modulation of cell surface glycoconjugates in the differentiating tissues. In this study, we show by lectin histochemistry and lectin blotting of proteins isolated by SDS‐PAGE, that Datura stramonium agglutinin (DSA) binds preferentially to differentiating tail bud cells. This lectin is specific for β1‐4‐linked N‐acetylglucosamine oligomers, such as the oligosaccharides of the poly‐N‐acetyllactosamine series that have been previously implicated in cell differentiation. Ultrastructural lectin cytochemistry indicates that at least some of the proteins binding DSA are localized extracellularly. The use of DSA as a teratogen resulted in embryos showing a variety of neural tube and notochord defects. We have also examined the binding of DSA to embryos that were treated with teratogenic doses of retinoic acid by sub‐blastodermal injection, and find that the DSA‐ binding patterns are perturbed. Analysis of DSA‐ treated embryos using the TUNEL technique indicated that cell death was not a factor in DSA teratogenesis. This strongly suggests that the glycoconjugates of the cell surface have a role in the normal differentiation of tail bud mesenchyme into the neuroepithelium of the secondary neural tube. Perturbations of glycoconjugate activity results in defects of the secondary neural tube and associated tail bud derivatives. © 1995 Wiley‐Liss, Inc.
Population dynamics of pedigree leopards, Panthera pardus ssp, in captivity
Authors: Shoemaker Alan H.
Published: June 2005

The demographic history of 4 races or subspecies of leopard, Panthera pardus, was reviewed from international studbook records dating back to 1953. The Chinese leopard has been the most common pedigree race maintained in captivity, a factor linked to the length of time (29 years) this subspecies has been in captivity. The relative youth of the wild‐born founders also helped them to adjust to captivity as well as live long reproductive lives. Today, however, this race is suffering from the ill effects of inbreeding due to the small founder size. This condition appears to be correctable now that additional specimens have been located.

Persian leopards have a larger founder size than the former race, but some of their ancestors were older animals at the time of acquisition. Because of this, their potential fecundity was probably depressed from psychological problems related to adjustment and a shorter life span in captivity. Two founding females experienced pelvic deformities while young, and few of their cubs survived because they all had to be delivered via caesarian section. This procedure also shortened the reproductive life of the females involved because the owning zoos refrained from breeding the animals in the leopards' later years.

Captive leopards appear to live longer than their wild counterparts, although precise data on wild populations is not available. In captivity many reach 12–15 years old, and exceptional individuals of several races have lived 20 years. Most captive‐born leopards begin breeding when they are 3 years old and continue until they are 8–10 years old. Reproduction in females usually ceases at 12–14 years, although males have a longer reproductive life, with several successfully breeding when 19–20 years old.
Behavioral development in okapis and giraffes
Authors: Horwich Robert H. , Kitchen Craig , Wangel Mark , Ruthe Richard
Published: June 2005

Observations on the behavioral development of two okapi calves and one giraffe calf were made at Brookfield Zoo. The following behaviors were monitored for 4 to 6 mo after birth; nursing duration and nursing attempts, mother‐infant distance, bunting the mother's udder, lying, moving, maternal grooming, mother and infant autogrooming, object licking, tail chewing, and contact by others in the herd. Behaviors in both species showed oscillating patterns with high levels of mother‐infant contact behaviors at 3–4 wk, 9–11 wk, and 14–15 wk in okapis. Giraffe infants showed similar oscillations with high periods of contact about 2–5 wk later than those in okapis. Other behaviors oscillated in concert with these, with specific correlations occurring between nursing behaviors and grooming behaviors.

A main difference between okapi and giraffe development centered around maternal motivation during the high contact (regressive) periods. In okapis, after 10–12 wk there was a low rate of nursing success, whereas in giraffes the percentage of success in nursing rose with later behavioral oscillations. The regressive periods became conflict periods in okapis, whereas in the giraffe, the mother initiated the periods. This difference was in accordance with the unique strategy of infant rearing in wild giraffes in which there is an extended “hider” period when older calves are left together in shaded areas with an adult sentry. Field studies also indicated probable oscillations of mother‐infant contact and a prolonged period of the mother initiating contact with her calf.
The physiological effects of psychological stress
Authors: Stoskopf Michael K.
Published: June 2005

The study of behavior is a powerful tool in the captive management of wild animals. It can, if properly applied, provide insight into a wide variety of problems. The interpretation of behavioral observations requires a firm understanding and characterization of the environmental parameters that can induce the physiological state of stress through neurological means in the study subjects. These factors include, but are not limited to, territorial factors, including social and physical accommodations, photo factors, and acoustical factors. Proper interpretation of behavioral observations also requires a basic understanding of the biochemical and physiological impacts of neuroendocrine‐mediated stress. These include alterations in an individual's ability to metabolize toxic substances, resist infections, and reproduce. Confounding effects of these alterations must be considered in the examination of behavioral data. The most powerful experimental designs in comparative behavior are those that concurrently examine environmental stressors, physiological status, and behavior.
Reproductive studies of the Oryx
Authors: Durrant Barbara S.
Published: June 2005

The genus Oryx comprises one species already extinct in the wild and others that are rapidly disappearing. It is important to understand the reproductive physiology of these species in order to ensure their successful captive propagation.

It was determined behaviorally and hormonally that the scimitar‐horned oryx's 21–22 d estrous cycle very closely resembled that of the domestic cow.

Four females of three species (Arabian, scimitar‐horned, and fringe‐eared oryx) were treated with prostaglandin (PG) and pregnant mares serum gonadotropin (PMSG) or follicle‐stimulating hormone (FSH). All animals responded to prostaglandin treatment with shortened cycles and behavioral estrus. Ovulation occurred in all females but only one responded to gonadotrophin treatment with a mild superovulation.

An embryo recovered from an Arabian oryx was frozen in liquid nitrogen for 6 months. Upon thawing, the normal‐appearing morula was surgically transferred to a scimitar‐horned oryx. The recipient failed to carry the embryo and returned to estrus within three weeks of the transfer.

It was demonstrated that induction of ovulation and synchronization of estrus can be achieved in the three Oryx species with PMSG or FSH combined with prostaglandin treatment.
Problems and experiences in performing artificial insemination in bonobos (Pan paniscus)
Authors: Matern Bernd
Published: June 2005

A report is given on the problems and the procedure of artificial insemination in the bonobo (Pan paniscus). In addition, the different possibilities and methods of the process of collecting sperm, its conservation, and determining the time of ovulation are discussed, as well as the various insemination techniques and their usage under practical conditions in zoological gardens.
Activity budgets and use of exhibit space by South American tapir (Tapirus terrestris) in a Zoological Park setting
Authors: Mahler Anne E.
Published: June 2005

Six individuals of Tapirus terrestris (two adult males, one juvenile male, and three adult females) were observed the first three months of 1982 at Audubon Park and Zoological Garden. Data for fourteen behavioral states were collected by scan sampling at ten‐minute intervals throughout the day and twice throughout the night in an open air, mixed‐species exhibit. The data were analyzed to calculate activity budgets and space use. Sleeping, eating, foraging, walking, and standing made up the major portions of the activity budgets. “Natural” activity patterns, as in the wild for browsing ungulates, were displayed under captivity in variously modified form. The characteristics of an individual, especially the reproductive state, affected both activity budget and space use. Zoo regimen significantly modified activity budgets and space use by the animals.
Integration of hand‐reared gorilla infants in a group
Authors: Meder Angela
Published: June 2005

Though many zoo‐born gorilla infants still have to be hand‐reared and sooner or later associated with conspecifics, preferably a group, neither the managing procedures nor the process of social integration has been recorded in detail thus far. The present study, conducted at the Frankfurt Zoo, deals with a simultaneous introduction of two hand‐reared infants, a male and a female, into a group. The procedure of the introduction was documented. Behavioral observations were made during 1.5 years of integration by using ad libitum and focal‐animal sampling methods. The findings were compared with some data collected during a previous introduction conducted by a different procedure. The results show that both introductions were successful insofar as the infants were able to live within the group after a given time. But social integration by the new introduction procedure took much longer than previous attempts.
Stress‐induced adrenal changes and their relation to reproductive failure in captive nine‐banded armadillos (Dasypus novemcinctus)
Authors: Rideout Bruce A. , Gause Gerald E. , Benirschke Kurt , Lasley Bill L.
Published: June 2005

Histological features of adrenal glands from captive and unstressed free‐ranging nine‐banded armadillos were compared to determine if undefined stress factors associated with captivity were capable of causing changes in adrenal morphology. Animals in captivity less than 3 mo showed histological features identical to unstressed free‐ranging animals. Animals in captivity 6 mo or longer, however, showed adrenal changes like those previously described in other mammals exposed to various types of stress, except that there was no accompanying increase in adrenal weight. Similar adrenal changes were found in free‐ranging animals exposed to extremely harsh winter weather. Females from both the chronic captive population and this stressed free‐ranging population were seen to suffer reproductive failure. Reproductive function in males was not affected. There was no detectable sex difference in gross or histological adrenal changes; however, previous reports indicate there is a sex difference in the secretory product from the adrenals of captive nine‐banded armadillos. A possible relationship between reproductive failure in the female and the sex difference in adrenal secretory products is discussed.
Meat eating and predation in captive‐born semi‐free‐ranging Lemur fulvus and caged Lemur macaco
Authors: Glander Kenneth E. , Freed Benjamin Z. , Ganzhorn Jörg U.
Published: June 2005

A group of brown lemurs, Lemur fulvus, and a group of black lemurs, Lemur macaco, at the Duke University Center for the Study of Primate Biology and History have been observed to capture and eat birds and lizards. Although vertebrate prey are not unusual for many carnivorous prosimians, folivorous prosimians never have been observed to take vertebrates in the wild and rarely even insects.
Wolf scent marking with raised‐leg urination
Authors: Mertl‐Millhollen Anne S. , Goodmann Patricia A. , Klinghammer Erich
Published: June 2005

Raised‐leg urinations were performed almost exclusively by dominant male and female wolves (Canis lupus). The alpha male and female in two captive groups showed full raised‐leg urinations (RLUs) throughout the year. Each alpha male and female sniffed and marked on one another's marks frequently; however, the pair that bred did more marking and more double marking. They increased their marking frequency prior to and during the breeding season, decreased it at the time of parturition, while the female was in the den, and then increased to a moderate level when the female took part in pack activities again. Because the alpha pair was the principal sender and receiver of the message within the group, it is likely that double marks function to maintain and advertise the pair bond. Because the group that did not breed also did not double mark frequently, the presence of double marking in a captive group may be diagnostic of the viability of the group as a pack.
An Artificial “gum‐tree” for marmosets (Callithrix j. jacchus)
Authors: McGrew W. C. , Brennan J. A. , Russell J.
Published: June 2005

Marmosets (Callithrix, Cebuella) in the wild gouge wells in trees and eat the exudates that accumulate there. An artificial gum‐tree was made of wooden dowel and filled with Acacia Senegal exudate (gum arabic) dissolved in water. Three families of marmosets avidly gouged and consumed gum from this device, showing all of the behavioral patterns described in nature. The gum‐tree cost little and was easy to make.
Urinary steroid evaluations to monitor ovarian function in exotic ungulates: II. Comparison between the giraffe (Giraffa camelopardalis) and the Okapi (Okapia johnstoni)
Authors: Loskutoff Naida M. , Walker Leslie , Ott‐Joslin Janis E. , Raphael Bonnie L. , Lasley Bill L.
Published: June 2005

Ovarian activity in the female giraffe was evaluated during the nonfertile ovarian cycle and during the terminal stages of gestation. Progesterone metabolites, in the form of pregnanediol‐3‐glucuronide (PdG), were measured in daily random urine samples collected from four adult parous giraffes. The follicular phase averaged 4.0 ± 0.1 days in length (N = 12; range 3–5 days) and peak PdG levels in the postovulatory period averaged 30.9 ± 1.7 ng/mg Cr (N = 12). PdG levels during the latter half of gestation greatly exceeded average luteal phase levels, which is in contrast to domestic ruminants. Prior to parturition, a marked decline in PdG excretion was evident, which may be useful for anticipating this event. These data serve to elucidate ovarian function in the mature female giraffe and to provide information concerning the physiologic role of certain anomalous ovarian structures. In addition, observed similarities in the pattern of PdG excretion during the nonfertile cycles of the giraffe and the okapi indicate similar underlying physiologic processes.
Floor‐coverings and hanging screens alter arboreal monkey behavior
Authors: McKenzie Susan M. , Chamove Arnold S. , Feistner Anna T. C.
Published: June 2005

The use of floor‐covering has been shown to substantially alter the behavior of captive terrestrial primates. Experiments with two large family groups of common marmosets (Callithrix jacchus) and two of cotton‐top tamarins (Saguinus oedipus) have shown that the type of floor‐covering also beneficially alters the behavior of arboreal monkeys, increasing use of the floor and decreasing inactivity. These effects increased over 2.5 mo, and appeared to be due to the reduced aversiveness of the floor. Hanging screens also produced beneficial effects.