bluuebunny/crossref_metadata_2025_split huggingface dataset:
“Apparent hydronephrosis” as a normal aspect of renal development in late gestation of rats: The effect of methyl salicylate
Authors: Woo David C. , Hoar Richard M. 
Published: June 2005

AbstractThe normal pattern of renal development late in gestation in rats involves a transient variation in growth rates. While the renal papilla is slowly and steadily increasing in length the renal parenchyma is rapidly and almost exponentially increasing in weight. This disparity in growth rates frequently results in a kidney that has an enlarged renal pelvis late in gestation; but this is only an “apparent hydronephrosis” since it disappears shortly after birth. Methyl salicylate retarded renal development, particularly growth of the renal papilla, and increased the number of both transient and permanent renal abnormalities in rat fetuses near term. Preliminary evidence suggested that if the renal papilla has reached a particular stage of development 1 day before birth, and is not accompanied by grossly apparent renal malformations, the kidney will be normal at weaning. However, at birth, kidneys with an absent renal papilla, but that appeared otherwise normal, cannot be differentiated on a gross anatomical level from those that are destined to be permanently abnormal.
Teratogenic effects of phleomycin in early chick embryos
Authors: Lee Hsin‐Yi , Cortés Jorge L. , Levin Martin A. 
Published: June 2005

AbstractEffects of phleomycin on chick embryos explanted at stages 4–7 and cultured for 19–21 h were studied. Concentrations of 0.1–0.8 μg/ml had marked effects on stages 4–5 embryos, but had no appreciable effects on stages 6–7 embryos. The most specific effect was progressive degeneration of neural tube tissue with increasing concentration. Neural tube closure was inhibited in most malformed embryos, especially of stage 4. Heart, foregut, somites, and blood islands were occasionally affected. Abnormalities may have been due to mitotic failure in the affected tissues, since many cells were arrested at interphase or prophase and showed nuclear enlargement. In severely affected tissues, cells showed pycnosis and nuclear fragmentation.
Estrogen, progesterone, and chromosome abnormalities in rabbit blastocysts
Authors: Widmeyer Maxine A. , Shaver Evelyn L. 
Published: June 2005

AbstractThe chromosome complement of blastocysts recovered from rabbits injected with estradiol or progesterone during the time of ovum maturation or the first cleavage division was studied. One chromosome anomaly, a triploid, was found in 72 control blastocysts analyzed; two, a triploid and a 44/45 mosaic, were found in 28 blastocysts from rabbits given estradiol 1 h after mating; and two trisomies in 48 blastocysts analyzed were recovered from rabbits treated with progesterone at 4 or 20 h after mating. An increased number of small blastocysts, which could not be analyzed, was found after estradiol treatment near the time of the first cleavage division. A lower mitotic index than normal was found in whole mounts of these blastocysts.
A direct analysis of early chick embryonic neuroepithelial responses following exposure to EDTA
Authors: Daniels Eugene , Moore Keith L. 
Published: June 2005

AbstractTransient exposure of chick neuroepithelial explants on Trowell‐type culture platforms to a chelating agent (EDTA) facilitated a direct study of the early sequences of presumptive malformative responses. Cerebral cortical tissues plus neuroretinal tissues with associated mesenchyme from 4 ½‐day embryos were studied on millipore tilters throughout a culture period of 120 h. Brief exposure (5–15 min) to divalent ion‐depleted media variably disturbed the organization of the neuroepithelial explants. The histological responses following subsequent culture in a complete medium included simulations of a number of CNS malformations (neuroretinal folds, rosette formations, ectopic cellular aggregations, and cellular depletions) previously produced by various teratogens. The adaptation of this procedure to the study of the response potential of the early embryonic tissues enabled delineation of the processes (the degree of interference on the adhesive mechanisms) presumably operative in the development of these malformations.
Greater sensitivity of female than male rat embryos to acetazolamide teratogenicity
Authors: Scott William J. , Butcher Richard E. , Kindt Charles W. , Wilson James G. 
Published: June 2005

AbstractIn a recent experiment involving administration of acetazolamide to pregnant rats a high proportion of survivors affected with the typical postaxial reduction deformity of the forelimb produced by this drug were females. A review of past experiments with this agent in this laboratory revealed that in all cases the percentage of affected females was greater than that of affected males. In some cases this difference was highly statistically significant. Thus, this most unusual agent, which produces a uniquely localized abnormality in the postaxial portion of the right forelimb, reveals another unusual effect by showing a predilection for female embryos.
6‐aminonicotinamide (6‐AN)‐induced abnormalities of the developing ependyma and choroid plexus as seen with the scanning electron microscope
Authors: Chamberlain J. G. 
Published: June 2005

AbstractVentricular surfaces in control and experimental day 13–21 rat brains were viewed with a Cambridge scanning electron microscope, Model S4 (40–30,000 X). Surfaces of ependyma and choroid plexus in offspring of pregnant females receiving the teratogen 6‐aminonicotinamide (6‐AN) showed retarded differentiation and reduced growth of microvilli and cilia; some flattened cells showed ruptured plasmalemmae.
The Saethre‐Chotzen syndrome
Authors: Kreiborg S. , Pruzansky S. , Pashayan H. 
Published: June 2005

AbstractFive individuals in four generations affected with the Saethre‐Chotzen syndrome are reported. Serial roentgencephalometric data obtained pre‐ and postoperatively on the proband were compared with similar measurements on the affected mother and maternal uncle, both of whom had not had operative corrections. Similarity in skull form among the affected individuals was demonstrated. Head circumference, as an index of cranial growth or intracranial capacity, was misleading in assessing the intellectual potential of the affected adults. In contrast, cranial capacity, as measured by the modulus, was found to be more reliable.
An unusual case of sirenomelia
Authors: Kohler H. G. 
Published: June 2005

AbstractA report is presented of a case of sirenomelia (symmelos). The affected infant was a partner in a monozygous monoamniotic twin pregnancy; the other twin is surviving and normal. In addition to anomalies regularly associated with sirenomelia such as bilateral renal agenesis, blind‐ending colon, severe abnormality of the bony pelvis, absence of both urethral and anal orifices, and medial position of the fibulae, the features of another syndrome were present composed of dextroposition and severe, complex abnormality of the heart, hyperlobation of lungs, and asplenia. Some aspects of this case seemed to be contrary to all experience of sirenomelia, e.g., the presence of both umbilical arteries, the absence of Potter facies, of hypoplasia of lungs, and of amnion nodosum, and the relatively long survival. This group of atypical features (with the exception of the normal number of umbilical arteries) can be explained by the fact that, unlike most other cases of sirenomelia, there was no oligohydramnios. This was so, presumably, because the normal twin maintained an adequate amount of amniotic fluid in the common amniotic sac.
Corticosterone‐induced isolated cleft palate in A/J mice
Authors: Hackman Robert M. , Brown Kenneth S. 
Published: June 2005

AbstractCorticosterone was administered sc daily on days 11–14 to pregnant A/J female mice, 5 mg producing 80% isolated cleft palate, 2.5 mg, 31%, and 1.25 mg, 6%. The prenatal death rate was not increased by corticosterone in litters with surviving offspring but did result in an increased frequency of totally resorbed litters. Among fetuses treated with corticosterone there was a dose related increase in hemorrhagic pigmentation of the fetal sac. Damage to the fetal sac by corticosteroids may be a basis for their teratogenic action.
The production of congenital malformations using tissue antisera XI. Antisera to acellular visceral yolk sac
Authors: Leung Christopher C. K. , Brent Robert L. , Koszalka Thomas R. 
Published: June 2005

AbstractA method has been developed for obtaining cell‐free visceral yolk‐sac membrane using the chelating agent tetrasodium salt of ethylenediamine‐tetraacetic acid (EDTA) combined with mechanical disruption of cells. Rabbit antiserum to this acellular membrane preparation when injected ip into 8‐day pregnant rats produced malformation, growth retardation, and fetal resorption. This yolk‐sac membrane was partially solubilized with sodium deoxycholate. The resultant insoluble material was further partially solubilized by 1 M NaCl and fractionated by molecular sieve chromatography on BioGel A‐5m to yield two fractions. The insoluble material after NaCl extraction was treated with purified collagenase to obtain a soluble and insoluble fraction. Rabbit antisera to all five soluble and insoluble fractions proved to be teratogenic in rat. Immunodiffusion studies indicated that there was at least one common antigen in all of these fractions; antisera to these fractions also crossreacted with soluble rat kidney. Fluorescent‐labeled antibody localization studies revealed that the teratogenic antibodies localized in the maternal renal glomerular basement membrane and the yolk‐sac placenta. The findings that (1) the hydroxyproline‐free collagenase‐treated residue was capable of stimulating the production of teratogenic antiserum and (2) rabbit antiserum against undenatured rat‐tail collagen was not embryotoxic provide evidence to support the view that antibodies against collagen fibers are not teratogenic. The hypothesis that teratogenesis resulting from yolk‐sac dysfunction induced by heterologous antibodies was discussed.
Transplacental uptake of 127mtellurium studied by whole‐body autoradiography
Authors: Agnew William F. 
Published: June 2005

AbstractWhole‐body autoradiographs and direct tissue counts demonstrated that, tellurium reached rat embryos during the period of teratogenic sensitivity for induction of hydrocephalus (gestation days 9–10). Progressively decreased concentrations occurred with increasing offspring age, but equilibration between maternal and fetal levels did not occur at any gestational stage. Autoradiographs of late fetuses revealed a prominent accumulation of tellurium by the choroid plexus and also development of the blood‐brain barrier to this metal.
Cleft palate formation: A role for pyridoxine in the closure of the secondary palate in mice
Authors: Miller Tony Jasper 
Published: June 2005

AbstractDietary pyridoxine deprivation in mice throughout pregnancy produced 20% cleft palate (CP). This frequency was significantly increased when either 4‐deoxypyridoxine or cortisone was administered during the period of palate closure. A low dose of cortisone given to pregnant mice fed a pyridoxine‐deficient diet produced a CP frequency greater than the sum of those produced by each teratogen alone. At a higher dose the interaction between cortisone and pyridoxine deficiency was additive. The effects of cortisone and pyridoxine deprivation were mitigated when pyridoxine was given during the time of palate shelf movement. Clearing arid staining for bone formation revealed general delay of ossification but no visible skeletal defects. Exencephaly, with a frequency of 0.4 %, was the only other gross defect seen after maternal pyridoxine deprivation.
Teratological experiments with ergotamine in mice, rats, and rabbits
Authors: Grauwiler J. , Schön H. 
Published: June 2005

AbstractPregnant mice, rats, and rabbits were treated orally with ergotamine during midgestation. In doses that affected maternal weight gain during treatment, ergotamine produced an increase in prenatal mortality in rats and evidence of fetal retardation in all three species. The results are discussed in connection with the vasoconstrictive action of ergotamine. A uterotonic effect may also be involved in the mechanism of action. No specific teratogenic activity was detected in any of the three species.
The teratogenicity of cadmium chloride in two stocks of Wistar rats
Authors: Barr Mason 
Published: June 2005

AbstractThe teratogenicity of cadmium chloride (16/μM/kg Cd++) was studied in Wistar rats from two commercial sources. Subcutaneous cadmium was not teratogenic. Intraperitoneal cadmium was highly teratogenic in both stocks when given on day 9, 10, or 11 of gestation. There were marked differences between the two stocks in fetal mortality and the incidence and types of malformations produced. Cadmium on day 9 produced an attenuation of the abdominal wall in 13–16% of the term fetuses. In one stock of rats, cadmium on day 10 produced reduction deformities of one forelimb similar to the previously reported acetazolamide syndrome in rats.
Ethylenethiourea: Teratogenicity study in rats and rabbits
Authors: Khera K. S. 
Published: June 2005

AbstractEthylenethiourea (ETU) was administered orally in single daily doses of 0, 5, 10, 20, 40, or 80 mg/kg to nulliparous rats and rabbits. In rats treatment was made from 21–42 days before conception to pregnancy day 15, and on days 6–15 or 7–20 of pregnancy, and in rabbits on days 7–20 of pregnancy. ETU induced meningoencephalocele, meningorrhagia, meningorrhea, hydrocephalus, obliterated neural canal, abnormal pelvic limb posture with equinovarus, and short or kinky tail after 10 mg/kg or more in all rat experiments. Fetal survival was not affected at any dose, whereas fetal growth was retarded at 40 and 80 mg/kg. The incidence of most of the deformities was dose dependent. Results from the rabbit study suggested an increased incidence of resorption sites and decreased brain weight in the group given 80 mg/kg, but no malformations were seen.
The morphology of various types of cell death in prenatal tissues
Authors: Schweichel J.‐U. , Merker H.‐J. 
Published: June 2005

AbstractThe morphology of physiological cell death and of necroses caused by treatment with various embryotoxic substances (cyclophosphamide, actinomycin D, vitamin A, vincristine, 6‐aminonicotinamide, 6‐mercaptopurine) and Mg deficiency were studied electron microscopically in rat and mouse embryos and fetuses. Three types of necroses were distinguished in control tissues. (1) Condensation and fragmentation of single cells undergoing phagocytosis, with lysosomal disintegration of the fragments in neighboring cells. (2) Primary formation of lysosomes in dying cells, with activation and subsequent destruction and phagocytosis of the fragments by neighboring cells. This type of cell death in most instances was found during destruction of organs and large cell units. (3) Disintegration of cells into fragments, which were optically no longer detectable, without involvement of the lysosomal system, e.g., in embryonic and epiphyseal cartilage before ossification. In cases of embryolethal toxic agents, e.g., Mg deficiency, cell necroses of large areas prevailed, which were characterized by typical pyknoses (rough, dense chromatin) and lack of lysosomes. In the case of teratogenic effects, however, substances that disturb replication, transcription, and translation (cyclophosphamide, actinomycin D, 6‐mercaptopurine) caused an increase in the number of necroses of type 1. It can, therefore, be assumed that under these conditions similar processes take place in physiological and experimentally induced necroses. After administration of vitamin A, labilization of lysosomes and necroses of type 2 were observed.
Pathology and epidemiology of conjoined twinning in swine
Authors: Selby Lloyd A. , Khalili Abbass , Stewart Robert W. , Edmonds Larry D. , Marienfeld Carl J. 
Published: June 2005

AbstractAmong 67 pigs with conjoined twinning observed over four and one‐half years the majority had partial rather than complete twinning. Fifty‐two percent of the 67 pigs were classified as syncephalus, i.e., with 1 head and two bodies. Epidemiologically, most were crossbred pigs born in February, March, and April on farms scattered throughout the swine‐producing regions of Missouri. In addition each was the only deformed pig in the litter. Comparison of some 32 swine husbandry variables for conjoined twin herds and matched‐paired environmental control herds did not identify any major environmental or genetic factors associated with conjoined twinning in Missouri swine.
Effects of alkaloids of Veratrum californicum on chick embryos
Authors: Bryden M. M. , Perry Clare , Keeler R. F. 
Published: June 2005

AbstractChicken eggs were treated with cyclopamine or jervine, either by yolk‐sac injection or application through windows made in the shell. Both methods resulted in a high mortality rate. No significant increase in the frequency of malformations resulted from yolk‐sac injection, but did occur after application of the compounds using windowed eggs. Retarded growth and development was also observed. Treatment with jervine at 14–28 h of incubation produced a high frequency of head malformations, but treatment later than this did not. Treatment with jervine at 30–40 h of incubation produced a high frequency of abnormalities other than head abnormalities, especially lordosis and rachischisis, whereas treatment before 28 h did not have this result. The frequency of head anomalies in the 16–28 h treatment groups was 30–60%, and the incidence of other anomalies in the 30–40 h treatment groups was 30–65%. Head abnormalities observed were cebocephaly, cyclopia, hydrocephalus, microphthalmia, meningocele, and encephalocele. Trunk and limb deformities were hemimelia, amelia, lordosis, and rachischisis. It was concluded that cyclopamine and jervine have a direct teratogenic effect on chick embryos. It appears that these compounds produce head malformations in chick and sheep embryos when they are exposed relatively at about the same developmental stage.
Teratogenic effects of cadmium in rats
Authors: Chernoff Neil 
Published: June 2005

AbstractThe teratogenic effects of subcutaneous injections of cadmium in CD rats were investigated. Injections of 4–12 mg/kg CdCl2 on 4 consecutive days beginning on days 13–16 of gestation resulted in a dose‐related rise in the fetal death rate, decrease in fetal weight, arid increase in the rate of anomalies. The anomalies included micrognathia, cleft palate, clubfoot, and small lungs. The lung/body weight ratios were significantly reduced in fetuses of animals injected with 8 mg/kg CdCl2 on days 14–17 of gestation. The data indicate that this was a specific retardation and not merely a reflection of differential organ growth rates and overall fetal growth retardation.
Alterations in the ontogeny and specific activity of phosphomonoesterases associated with abnormal chondrogenesis and osteogenesis in the limbs of fetuses from folic acid‐deficient pregnant rats
Authors: Jaffe Norman R. , Johnson E. Marshall 
Published: June 2005

AbstractA transient maternal folic acid‐deficiency resulted in alterations in the ontogeny and specific activity of pH‐dependent phosphomonoesterases from the limbs of rat fetuses. Associated with the biochemical lesion was an anomalous pattern of chondrogenesis and osteogenesis. These results offer an explanation for the limb malformations observed in near‐term fetuses and further implicate the phosphomonoesterases in cartilage and bone development.
Epidemic waves in the prevalence of anencephaly and spina bifida in New York State
Authors: Janerich Dwight T. 
Published: June 2005

AbstractThis study examines the prevalence of anencephaly and spina bifida among births in New York State from 1945 through 1971. The data suggest that the regression of the epidemic that peaked in the early 1930s may be continuing. The apparent leveling of the rate during the 1950s may have been another of the epidemic waves or peaks that have occurred in the last 70 years.
Skeletal deviations in rats: Malformations or variations?
Authors: Dr. Kimmel Carole A. , Wilson James G. 
Published: June 2005

AbstractSkeletal variations were studied in 20‐day rat fetuses from pregnant females given acetazolamide, actinomycin D, or sodium salicylate and in vehicle‐treated and untreated controls. A slight increase over untreated control values as regards resorptions, malformations, and certain skeletal variants was noted in some vehicle‐treated groups. Supernumerary 14th ribs were designated as rudimentary (less than half the length of the 13th rib) or extra (half or greater than half the length of the 13th rib) on the basis of actual measurement showing a bimodal distribution in length. The occurrence of rudimentary 14th ribs was highly variable after vehicle or teratogen treatment. Extra 14th ribs occurred in a dose‐related fashion after actinomycin D (days 7 and 9) and sodium salicylate (which sometimes also produced 15th ribs), but not after acetazolamide treatment. Sternebrae were variable in form after most treatments and these changes showed a slight but insignificant increase after actinomycin D or sodium salicylate on day 9. The incidence of variations of vertebral centra was highly changeable after all treatments but was consistently greater after sc treatment with water or acetazolamide and appeared to be dose related after sodium salicylate. The authors believe that none of these skeletal variants should in themselves be considered as malformations. The possibility exists that extra 14th ribs could be regarded as indicators of teratogenic potency of a drug at some higher dosage; but the data presented did not demonstrate the usefulness of the other skeletal variants examined as signals of teratogenic potential.
Questions concerning the possible association of potatoes and neural‐tube defects, and an alternative hypothesis relating to maternal growth and development
Authors: Emanuel Irvin , Sever Lowell E. 
Published: June 2005

AbstractThe hypothesis concerning the possible association of potatoes and neural‐tube defects has been reviewed. The bulk of epidemiological evidence presented to date fails to support this hypothesis. An alternative hypothesis is proposed for the etiology of anencephalus and spina bifida involving the interaction of three categories of causal factors: genetic, immediate, which pertains to the pregnancy in question, and intergenerational, which pertains to the growth and development of mothers of affected children. The epidemiological evidence is reviewed that supports an intergenerational concept, and includes the socio‐economic gradient, secular and geographic Variation, and migrant studies. The hypothesis is consistent with the complex epidemiological patterns that have emerged, and raises the question of the relevance of reliance on specific teratogens as the sole extragenetic explanations for these malformations. It is more likely that these defects are truly multifactorial in origin and relate to a complex interplay of biological and social factors rather than to single teratogens.