bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of ethylenebis[dithiocarbamic acid] disodium salt (nabam) and ethylenebis[dithiocarbamato]manganese (maneb) on Xenopus laevis development
Authors: Bancroft Roger , Prahlad K. V. 
Published: June 2005

AbstractThe fungicides ethylenebis [dithiocarbamic acid] (nabam) and ethylenebis [dithiocarbamato] manganese (maneb) were dissolved in a modified Holtfreter's solution at concentrations of 0.1–5 ppm. Thirty to 60 yolk‐plug Xenopus laevis embryos were placed for 1–10 days in 200 ml of different concentrations of the fungicide solution. Treated and control (Holtfreter's only) embryos were fixed in Bouin's fluid or formalin for light microscopy, and in glutaraldehyde‐formaldehyde for electron microscopy. Gross morphological and histological observations were made. The first changes observed in experimental embryos was a slight growth retardation and a transient absence or reduction in melanogenesis in the eye and on the rest of the body. The tail was shortened and the notochord had a distinct waviness. Animals in higher concentrations were unable to swim as well as controls. Histological examination, both light and electron microscopic, showed a general decrease in melanin content of the melanosomes in the pigmented retina. The notochord was increased in diameter; in sagittal sections the foldings were obvious. These results indicate that minute doses of these commonly used fungicides are harmful to the normal development of amphibian embryos.
Action of the phenothiazine derivative methophenazine on prenatal development in rats
Authors: Horvath Cécilia , Druga Alice 
Published: June 2005

AbstractSingle doses of 100–400 mg/kg or multiple doses of 10 or 50 mg/kg of the phenothiazine derivative methophenazine were given per os to Wistar rats at various times on the 7th‐14th days of gestation and the fetuses examined near term. Results indicated that methophenazine was mainly embryolethal when administered on the 8th‐11th days, and was teratogenic at later times, producing types of malformations that depended on the day of treatment, the most susceptible period being the 13th and 14th days of gestation. Teratogenicity occurred only when the dosages were highly toxic to the pregnant rats. Riboflavin given ip on the 14th day significantly reduced the embryolethal but not the teratogenic action of methophenazine.
Teratogenicity of cytochalasin D in the mouse
Authors: Shepard Thomas H. , Greenaway Jean C. 
Published: June 2005

AbstractCytochalasin D, a mold metabolite identified in food, was injected intraperitoneally in doses of 0.4 to 0.9 mg per kilogram on gestational days 7 through 11 and produced evidence of teratogenicity in two out of three strains of mice. Exencephaly, hypognathia and axial skeletal defects were found in strains C57BL/6J and BALB/c while no increase in defects was observed in the Swiss Webster strain. In all three strains, a significantly increased resorption rate was found. Oral doses of approximately 7.0 mg per kg on days 7 through 11 in the BALB/c produced exencephaly in the offspring. Autoclaved cytochalasin D retained its teratogenic potential.
Anencephaly with incomplete twinning (diprosopus)
Authors: Riccardi Vincent M. , Bergmann Cynthia A. 
Published: June 2005

AbstractA case of diprosopus with anencephaly is presented. It is suggested that such concurrence of neural tube defects and incomplete twinning corroborates the notion that a single pathogenetic mechanism may be common to both neural tube defects and monozygotic twinning.
Bovine like‐sexed male twins with chromosomal chimerism
Authors: Miyake Yoh‐Ichi , Yamanaka Harumichi , Deguchi Eizaburo , Ishikawa Tsune 
Published: June 2005

AbstractSex‐chromosomal chimerism (XX/XY) was described in a pair of bovine like‐sexed male twins. One of the twins showed malformed external genitalia, and the other was phenotypically normal. It is proposed that sex‐chromosomal chimerism is associated with a choriovascular anastomosis between like‐sexed twins examined and “female fetus” which may be overlooked at parturition.
The effect of intrauterine position on the radiosensitivity of rat embryos
Authors: Ward W. F. , Aceto H. , Karp C. H. 
Published: June 2005

AbstractRats were exposed to gamma rays or helium ions on one of days 4‐9 of gestation. Embryonic survival was recorded as a function of intrauterine position at autopsy on day 20 of gestation.Embryos located at the ovarian and cervical ends of the uterus experienced higher rates of mortality than did their littermates located at the middle of the uterine horn. This effect was observed in litters exposed to both radiation modalities on all days studied. The influence of intrauterine position on embryonic survival was directly proportional to radiation dose and to the number of fetuses occupying the uterine horn. Under the least advantageous conditions (i.e., a crowded uterine horn exposed to a moderately high radiation dose), the cervical embryo's probability of survival was less than half that of the litter as a whole.A disproportionately high rate of embryonic mortality at the cervical position was also observed in litters irradiated under hypoxic conditions, suggesting that the non‐random distribution of radiation effect was not the result of variations in oxygen concentration within the uterus.In contrast, there was no indication that intrauterine position influenced the distribution of gross morphologic abnormalities in irradiated litters.
Patterns of combined limb malformations
Authors: Castilla Eduardo Enrique , Frias Maria Luisa Martinez , Paz Joaquin Eugenio 
Published: June 2005

AbstractSeven different limb malformation types were defined in 544 affected newborns, apparently free from other anomalies, obtained from a series of 297,299 livebirths. These seven malformation types were: polydactyly, limb reduction, brachydactyly, symphalangy, syndactyly and split hand/foot. One anomaly type was present in 472 newborns (1.58/1,000) and two or three in 72 (0.24/1,000).The observed combinations of two or three limb malformation types cannot be explained as chance association. Therefore, a common etiopathogenic mechanism has to be considered when two or more limb malformation types are combined in a given individual.The most frequent observed combinations were: reduction‐brachydactyly, reduction‐syndactyly, brachydactyly‐syndactyly, polydactyly‐syndactyly, and reduction‐brachydactyly‐syndactyly.Based on affected limb distribution, sex ratio, and familial recurrence rates, it is suggested that a reduction anomaly is the primary component in all tested combinations while syndactyly tends to be a secondary one when combined with any other limb anomaly type.
Palate morphogenesis: II. Contraction of cytoplasmic processes in ATP‐induced palate rotation in glycerinated mouse heads
Authors: Wee Elizabeth L. , Zimmerman Ernest F. 
Published: June 2005

AbstractIt has been previously shown that non‐muscle contractile system(s) exist in mouse palate mesenchyme underlying the palate epithelium before shelf rotation. In order to obtain evidence that the non‐muscle contractile system(s) function to elevate the palate, glycerinated heads have been incubated with ATP. It was shown that 5 mM ATP and a 30 min incubation at 25°C stimulated palate rotation optimally. Elevation of the anterior end of the palate was nearly complete (PSI = 3.90, p<10−6). Although rotation of the posterior end was significant (p<0.02), movement was limited (PSI = 1.70). Light microscopy of the palate revealed that ATP caused a marked condensation of the cytoplasmic processes of the mesenchymal cells. The contraction of the processes of the mesenchymal cells induced by ATP increased roughly with increased palate shelf rotation and was greater at the peripheral than at the internal mesenchyme. Cytochalasin B pre‐treatment at 40 μM completely blocked the ATP‐induced rotation at the anterior end. The effect of other nucleotides on palate rotation was tested. GTP caused a significant stimulation of anterior shelf rotation (p<0.005), which was less than ATP, while ADP and CTP were ineffective. Low temperature (6°C) prevented the ATP‐induced shelf rotation. These results suggest that the non‐muscle contractile cells in the mesenchyme play a role in palate elevation and that contraction of the actomyosin containing microfilaments supplies the motive force.
Changes in the mouse neuroepithelium associated with cadmium‐induced neural tube defects
Authors: Webster William S. , Messerle Karin 
Published: June 2005

AbstractThe aim of this study was to investigate the teratogenic action of cadmium (Cd) on the developing mouse CNS. Pregnant mice were injected with 4mg/kg CdCl2 on day 7, 8, 9, or 10 of gestation. These animals and saline injected controls were sacrificed either on the day before birth or at various times up to 48 hours after injection and the embryos examined grossly and histologically.Exencephaly occurred after Cd treatment on day 7 or 8 and its development was examined in day 8 embryos. Eight hours after Cd injection many cells of the closing neural plate contained dense‐staining inclusions, thought to be autophagic vacuoles. After 24 hours this damage had almost disappeared, but the anterior neural folds, although looking histologically normal, were more open than in controls. Forty‐eight hours after injection it was apparent that this part of the neural tube was not going to close and would result in exencephaly.Cd exposure on day 9 or 10 did not cause gross CNS defects such as exencephaly. On both days, twelve hours after Cd injection, similar dark‐staining inclusions were seen in many cells throughout the CNS. After twenty‐four hours there were variable amounts of cell death, resulting in some embroys in breakdown of parts of the wall of the neural tube. Forty‐eight hours after treatment all inclusions and cellular debris had disappeared, indicating repair had taken place, but in some embryos, treated on day 9, severe lasting damage was seen as dorsal openings in the previously closed neural tube.
Frequency of congenital abnormalities and of anatomical variations among JAX rabbits
Authors: Crary Dorcas D. , Fox Richard R. 
Published: June 2005

AbstractThe frequency of congenital abnormalities and anatomical variations as observed among JAX rabbits is reported. Data were drawn from 32,082 inbred and partially inbred rabbits and 3,208 hybrids from the colony of the Jackson Laboratory over an eight‐year period. Data reported here include stillbirths, rabbits dying from natural causes, and those killed for specific experimental regimens. Frequency data are based on the number of abnormalities observed in each category as a function of the total number of animals necropsied. This is approximately 95% of the animals born during the eight‐year period and gives the frequency of abnormalities within each category rather than the number of individuals with one or more abnormalities. Anatomical variations have been found in almost all organ systems of JAX rabbits. Their presence adds to our knowledge of the characteristics of these strains, a knowledge that is critical to the understanding of the results of experimental manipulation or for determination of the presence of new mutations. There is considerable between‐strain variation. Where frequencies are relatively high, the conditions are either known or suspected to be of genetic origin. Most of the anomalies are not deleterious, or their frequency is so low as to cause no prublems within the colony. Hybrid populations have substantially fewer anomalies than do the parental strains. Where frequency is relatively high, it tends to be intermediate between the parental strains.
Reduction of catecholamine‐induced cardiovascular malformations in the chick embryo with metoprolol
Authors: Kuhlmann Randall S. , Kolesari Gary L. , Kalbfleisch John H. 
Published: June 2005

AbstractIt has been documented that activation of the β1‐adrenergic receptor mechanism is directly related to cardiovascular malformations associated with the heart and great vessels of the embryonic chick. These adrenergic receptors are believed to be present and functional in the innervated and noninnervated embryonic heart at early stages of development. The present study examined the effects of four sympathomimetic cardioactive amines on chick cardiovascular morphogenesis at Hamburger and Hamilton stage 24. Special attention was directed toward understanding dopamine teratogenicity. In order of decreasing potency at the maximum teratogenic dose (dopamine > isoproterenol > epinephrine > norepinephrine) each drug was found capable of producing aortic arch anomalies of the third, fourth, and sixth aortic arches and ventricular septal defects (VSD). A new specific β1‐adrenergic antagonist, metoprolol tartrate, was employed in an attempt to lower the incidence of these cardiovascular malformations. Pretreatment with this selective β1‐blocker profoundly reduced the incidence of malformations within any aminetreated group. These experiments demonstrate that dopamine, as well as the other sympathomimetic amines, is a potent teratogen and most likely produces these cardiovascular malformations by primarily stimulating the β1‐adrenoreceptor in the embryonic chick.
Involvement of GABA in palate morphogenesis and its relation to diazepam teratogenesis in two mouse strains
Authors: Wee Elizabeth L. , Zimmerman Ernest F. 
Published: June 2005

AbstractPrevious studies have indicated that serotonin and acetylcholine stimulate palate shelf reorientation. The present studies were undertaken to determine whether γ‐aminobutyric acid (GABA) functions as an inhibitory neurotransmitter in the palate and whether diazepam mimics GABA to inhibit shelf reorientation and cause cleft palate. First, it was shown that 10−4 M GABA inhibits palate shelf reorientation in day 14.5 AJ embryos cultured for 2 hours. Anterior palate reorientation stimulated by 10−5 M serotonin was decreased by GABA; 10−5 M picrotoxin (GABA antagonist) stimulated anterior shelf reorientation and reversed the effect of GABA. Diazepam (10−4 M) partially inhibited palate shelf reorientation and that stimulated by 10−5 M serotonin. Diazepam (400 mg/kg) was administered to AJ mice at day 13.5 of gestation and embryos were cultured at day 14.5. The inhibition produced by diazepam was significantly reduced by 10−5 M picrotoxin. The teratogenic effect of diazepam was compared with AJ and Swiss‐Webster Vancouver (SWV) inbred strains. Diazepam produced greater clefting in SWV mice (57% net) than in the AJ (18% net) when compared to their water‐ and food‐starved controls. The greater sensitivity of the SWV strain than the AJ strain to diazepam, as well as to GABA, was also observed in embryo culture. GABA (10−5 M) markedly inhibited posterior palate reorientation and reversed the stimulation produced by bethanechol in SWV mice. The inhibitory effects of GABA on the posterior palate were partially reversed by picrotoxin. Furthermore, diazepam inhibited palate reorientation either when administereted to the pregnant dam or added in embryo culture. Picrotoxin significantly antagonized these effects. Thus both GABA and diazepam inhibited palate reorientation. The SWV strain was more sensitive to both agents than the AJ; the posterior end was preferentially affected in SWV while the anterior was more sensitive in the AJ mouse. These results suggest that (1) GABA may function as an inhibitory neurotransmitter to regulate palate reorientation, (2) diazepam may cause cleft palate by mimicking GABA to inhibit shelf reorientation, and (3) these events are genetically regulated in inbred mouse strains.
Methyl mercury toxicity in the chick embryo
Authors: Greener Yigal , Kochen Joseph A. 
Published: June 2005

AbstractThe toxicity of methyl mercury (mHg) in the developing chick embryo was investigated. The relationship of dose, time of administration (i.e., days 4–9 of development), and body levels of mercury was examined. The LD50 for mHg injected into the yolk sac on day 5 of incubation was 40–50 μg. Embryos dying within 24 hours showed increased total body mHg levels when compared to survivors (219 ± 67 vs. 105 ± 41 μg/gm, mean ± SD). Absorption was dose‐related, with a good correlation between mortality and body, blood, and brain levels. Daily analysis of body mHg levels after injection on day 5 showed continued mHg accumulation (0.88 ± 0.35 μg/embryo/day). However, the rate of embryo growth exceeded the rate of mHg absorption, resulting in a progressive decrease in mHg in concentration in tissues (from 94.5 ± 34.2 μg/gm on day 6 to 45.3 ± 13.4 on day 9). Administration after day 5 resulted in a significant reduction in levels of mHg in the brain on day 18 (from 11.4 ± 2.1 μg/gm when given on day 5 to 8.4 ± 2.3 when given on day 9) and in mortality (from 64% to 33%). Because blood mHg levels remained unchanged, the increased brain levels and higher mortality early in embryogenesis may reflect facilitated transfer of mHg across a poorly developed blood‐brain barrier. Later in development, the reduced mortality and lower brain mHg levels correspond to the formation of specialized interendothelial junctions and a more effective blood‐brain barrier.
Assessment of adult skeletons to detect prenatal exposure to acetazolamide in mice
Authors: Beck Sidney L. 
Published: June 2005

AbstractA skeletal variant assay system (SVAS) consisting of a group of 88 spontaneously occurring qualitative variations of the adult mouse skeleton was applied to CD‐1 animals that had been exposed in utero to 0, 200, or 1,000 mg/kg/day of the sodium salt of acetazolamide dissolved in distilled water, presented by SC injection of the dam during day 8 or days 9–11 of gestation. Two separate series of experiments were performed, and skeletons were examined at postnatal 62 ± 2 days.Variation occurred in 62 and 67 characters in the two series. Frequencies of occurrence differed from untreated (UNTD) and vehicle‐treated (VEH) values of substantial numbers of variants in a dose related manner for both series in both treatment regimes as did the number of variants which showed significantly different frequencies (P < .01) in comparisons of experimental with either UNTD or VEH. At the high doses 12 and 16 variants occurred with significantly different frequencies from UNTD in day 8 treatments in the two series, and 15 and 19 variants differed in the days 9–11 treated group. Contrasting high‐dose animals with appropriate vehicle controls revealed differences in 13 and 12 variants in day 8 treatment groups and in 18 and 15 variants in days 9–11 groups.Agreement between the two series was good, especially in the D9–11 treatments. Several variants differed significantly from both UNTD and VEH in both series of experiments. Among these were a number which appeared more or less specific to acetazolamide exposure. They include: day 8 treatments–accessory parietal, frontal extension, and 27 presacral vertebrae; day 9–11 treatments—sacral fusions in dorsal processes and vertebral bodies, and caudal fusions and malformations; both sets of treatments—lumbar fusions, and fusions of the transverse processes of the sacral vertebrae. Other importantly affected variants, also seen in exposure to other compounds include: day 8 treatments—abnormal metoptic roots; day 9–11 treatments—accessory mental foramen, foramina transversaria imperfecta of the atlas, arch foramen of the fifth cervical (C) vertebra, malformed sternebrae, fossa olecrani perforata, and fewer than 30 caudal vertebrae; both treatment regimes—parted frontals, accessory transverse foramina in C3–C6, reduced articular processes on the thoracic vertebrae, and 14 ribs.By all criteria applied, the SVAS is able to detect prenatal exposure to acetazolamide in adult skeletons even in the absence of any gross morphological abnormalities.
Ultrastructure of initial nasal process cell fusion in spontaneous and 6‐aminonicotinamide‐induced mouse embryo cleft lip
Authors: Trasler D. G. , Ohannessian L. 
Published: June 2005

AbstractA search was made for cell ultrastructure differences in the initial fusion process of the medial and lateral nasal processes in mouse embryos of the following types: A/J with 12% cleft lip (CL), CL/Fr with 23% CL—both cleft‐lip‐predisposed strains, CL/Fr 6‐aminonicotinamide (6AN)‐treated (94% CL) and controls from the C57BL/6 strain (0% CL) and dancer stock (0% CL). No detectable differences were found between the A/J and CL/Fr strains and the controls in the epithelial cells showing initial contact and fusion. Epithelial surfaces not in contact in controls and where clefts were developing were smooth. Cells approaching or in contact had cell projections, intercellular junctions, desmosomes, and microfilaments demonstrating firm contact between the apposed epithelia. It has been postulated that spontaneous cleft lip was due to a predisposing face shape bringing about a failure of contact in some embryos and in others where contact was achieved fusion was normal. These data support this view. The situation, however, in 6AN‐treated embryos is different. A few 6AN‐treated embryos showed abnormal contact that appeared malpositioned and tenuous. The teratogen also caused increased cell death and a denser epithelium and mesenchyme. Thus 6AN‐induced cleft lip could be due to the epithelial cell changes and/or to the reduction in size of the nasal processes.
Iron deficiency in the rat: Biochemical studies of fetal metabolism
Authors: Mackler Bruce , Grace Richard , Person Richard , Shepard Thomas H. , Finch Clement A. 
Published: June 2005

AbstractThe effects of dietary‐induced iron deficiency on fetal and maternal metabolism were studied in the rat. Concentrations of phenylalanine, but not tyrosine, were significantly elevated in plasma from iron‐deficient maternal and fetal rats at day 20 of gestation with individual fetal plasma levels of phenylalanine as high as 10 mg per 100 ml. Concentrations of total 5‐hydroxyindole compounds were significantly decreased in brain tissue from iron‐deficient fetuses (day 20 of gestation), suggesting that synthesis of the compounds may be inhibited by iron deficiency. Mitochondrial NADH oxidase activity was markedly decreased (60%) in homogenates of fetuses at day 14 of gestation and may account for the high fetal resorption rate and small fetal size observed in the rat in iron deficiency.