ISSN:0040-3709    

DOI:10.1002/tera.1420010102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1968

数据来源: WILEY

摘要:

AbstractCyclopamine, and its glycoside alkaloid X, along with jervine and veratrosine, induced cyclopian malformations in offspring born to ewes ingesting these compounds on the fourteenth day of gestation. Other steroidal alkaloids with somewhat similar structures and various other steroidal compounds including certain hormones and steroidal sapogenins did not induce the malformation.

ISSN:0040-3709    

DOI:10.1002/tera.1420010103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1968

数据来源: WILEY

摘要:

AbstractPregnant Wistar Albino rats were injected intraperitoneally with the thyroid stimulating hormone (TSH), obtained from several different suppliers, and with the dye trypan blue. Twenty USP units of TSH were injected on days 7 to 10 of pregnancy, one quarter of the total dose each day. Trypan blue was injected as a single subteratogenic dose (0.6 mg/100 gm maternal body weight) on day 8. Autopsy was on day 20. Some TSH prepared as a pituitary extract possessed very weak teratogenic activity, possibly limited to the production of hydronephrosis and hydroureter. Other TSH samples similarly prepared had no embryotoxic or teratogenic effect. Thyrotropin prepared from bovine serum exhibited distinct teratogenic activity causing the production of various malformations in the offspring of treated mothers. A subteratogenic dose of trypan blue enhanced the teratogenic activity of the serum prepared TSH sample but had no effect on TSH prepared from pituitary glands. The results of this experiment suggest that there is something in the nature of preparation of TSH from bovine serum that causes it to possess teratogenic activity.

ISSN:0040-3709    

DOI:10.1002/tera.1420010104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1968

数据来源: WILEY

摘要:

AbstractAbnormal development of the embryonic axis is one consequence of injection into the yolk sacs of 48‐hour chick embryos of each of the following teratogens: actinomycin D, puromycin, deoxyguanosine. Rumplessness and trunklessness are consequences of treatment with actinomycin D or puromycin; thoracic constrictions are consequences of treatment with deoxyguanosine. Treatment with both actinomycin D and deoxyguanosine, under certain conditions of dosage and developmental timing, results in an increase in the frequency of rumplessness and trunklessness; the same is true for combined treatment with puromycin and deoxyguanosine. Although deoxyguanosine treatment of 72‐hour embryos is also associated with rumplessness, evidence is presented that deoxyguanosine‐induced rumplessness does not contribute to the effects obtained with embryos treated at 48 hours incubation age with these combinations of teratogens. Treatment with both actinomycin D and deoxyguanosine can result in an increase in the frequency of thoracic constrictions; treatment with both puromycin and deoxyguanosine, in a decrease. These interactions in teratogenesis between deoxyguanosine and actinomycin D and between deoxyguanosine and puromycin indicate that the distribution in the embryo of each teratogen is more widespread than suggested by the morphological consequences associated with each individ

ISSN:0040-3709    

DOI:10.1002/tera.1420010105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1968

数据来源: WILEY

摘要:

AbstractA comparison was made of early face embryology in the inbred A/J mouse strain with a spontaneous frequency of about 12% cleft lip and the C57BL/6J strain which virtually never has cleft lip. From the time of their appearance the medial nasal, lateral nasal and maxillary processes are connected by an isthmus. Subsequently there is fusion between the adjacent epithelia of medial and lateral nasal processes. Failure of this fusion, followed by breakdown of the isthmus, results in cleft lip. Just before and when the adjacent epithelia of medial nasal and lateral nasal processes meet and fuse at the posterior end of the nasal pit, the medial nasal processes of A/J embryos were more prominent, more medially placed, and diverged less than those of C57BL/6J. It is suggested that (a) cleft lip is a threshold character or quasi‐continuous variant such that a very slight change in the divergence of the medial nasals leads to their partial or completelack of fusionwith the lateral nasals. This is followed by a lack of fusion of medial and maxillary processes, and a complete or partial breakdown of the isthmus, resulting in a cleft lip; (b) the strain differences in type of aspirin‐induced cleft lip and in topography and growth of the facial processes between the two strains are causally related to the A/J predisposition to cleft

ISSN:0040-3709    

DOI:10.1002/tera.1420010106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1968

数据来源: WILEY

摘要:

AbstractAcetazolamide and ethoxzolamide incorporated into the diet of pregnant rats at 0.3% or 0.6% level caused localized appendicular malformation typically affecting the distal, postaxial part of the right forelimb. Other malformations and intrauterine death were also more frequent than in the offspring of untreated rats.Treatment on day 10 or 11 of gestation with 1000 mg/kg of acetazolamide injected subcutaneously also produced a high incidence of typical abnormalities but similar treatment on day 9 or 12 failed to do so. The susceptible period of rat embryos to this agent is thus defined as the tenth and eleventh days.Analysis of maternal blood after teratogenic treatment revealed that both acetazolamide and ethoxzolamide produced metabolic acidosis but little change in other electrolytes except potassium, which was sharply reduced. It was not possible to prevent the occurrence of characteristic malformations by supplemental dosing with potassium. The production of litters with acetazolamide‐induced defects was associated with loss of maternal weight after treatment exceeding 10% of pretreatment weight. It has not been possible to produce typical defects using the potent diuretic furosemide.Analysis of embryos from untreated females revealed that carbonic anhydrase does not appear in measurable amounts in the developing rat until the thirteenth day of gestation, making highly unlikely the possibility that the drug's teratogenic action is associated with carbonic anhydrase inhibition in the embry

ISSN:0040-3709    

DOI:10.1002/tera.1420010107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1968

数据来源: WILEY

摘要:

AbstractFertilizedRana pipienseggs were treated with 0.5% solution of trypan blue in spring water. The stage at which the dye was added and the duration of exposure were varied.The first signs of aberrant development appeared at late stage 13 at which time the neural folds were abnormal and elongation of the body axis was inhibited. Subsequent development resulted in microcephalic larvae with foreshortened trunks and kinked or malproportioned tails. Such embryos never exhibited spontaneous muscular contractions although they may survive for 10 to 12 days and come to resemble stage 21 larvae.Microscopic analysis revealed that (1) the notochord was either completely absent or present only in the anterior half of experimental embryos, (2) adjacent to the notochordal abnormalities the lateral mesoderm formed an unsegmented mass whose left and right sides fused beneath the neural tube, and (3) malformations of the forebrain included absence of the diencephalon, optic cups, and cranial ganglia.Trypan blue was never found within the cells of the embryos.The critical period of response to trypan blue extended from stage 10 through stage 14. Animals growing in dye solution since fertilization but removed to fresh spring water prior to stage 10 differentiated normally.

ISSN:0040-3709    

DOI:10.1002/tera.1420010108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1968

数据来源: WILEY

摘要:

AbstractEmbryos from maternal rats maintained on a riboflavin‐deficient, galactoflavin‐augmented diet were compared by gross and histologic examinations with normal controls. On day 11 of gestation no differences were noted between control and treated embryos; on days 12 and 13 the treated embryos were smaller in overall size; and on day 14 the rate of differentiation of tissues of the treated embryos was delayed.The embryonic mortality occurred between day 11 and day 15. Serial sections of day‐14 treated embryos consistently contained extensive areas of necrosis in the mesoblast of the extremities and first branchial arch. A less frequent but similar lesion was found in the central nervous systems in two of four treated embryos examined on day 14. The pathologic lesion resembles the normal cell death which is part of the sculpturing process of developing extremities, but was of much greater magnitude. In addition, studies of sections of the extremities of the treated day‐14 embryos demonstrated a reduction in the number of cellular mitoses. By day 15 the necrosis had disappeared, the mode of clearing presumably being due to macrophage action as evidenced by photographs and by the presence of acid phosphatase‐containing cells in the areas of phagocytosis.In the early stages of mesenchymal condensation the treated specimens evidenced digital fusion but measurements of the relative total volume of mesenchyme were similar in treated and control specimens.Histochemical studies of the treated embryos but not the placentas or maternal tissues demonstrated an overall decrease in the reactions for succinic dehydrogenase from day 12 to day 17. Levels of malic and lactic dehydrogenases and alkaline and acid phosphatases were not decreased in the treated embryos when measured histoc

ISSN:0040-3709    

DOI:10.1002/tera.1420010109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1968

数据来源: WILEY

摘要:

AbstractStudies of the tissues of embryos and fetuses of rats treated with a riboflavin‐deficient, galactoflavin‐augmented diet during pregnancy were performed, and demonstrated that the activities of the succinic and DPNH oxidase systems (the terminal electron transport systems) were markedly reduced from control values during the critical period of development (days 12 thru 16 of gestation). The activities of the electron transport systems of placental tissue and maternal heart tissue were unaffected during the same period, suggesting that fetal tissue is particularly susceptible to the effects of riboflavin deficie

ISSN:0040-3709    

DOI:10.1002/tera.1420010110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1968

数据来源: WILEY

摘要:

AbstractGraded dosages of the niacin antimetabolite 6‐aminonicotinamide (6‐AN) were incorporated in the culture media of explanted day 10 rat embryos or injected directly into amniotic cavities of day 15 embryos. Regardless of the route of administration the resultant decreased growth and abnormal development were related to the concentration of the antimetabolite. Culturing embryos for 22–26 hours with 5 to 20 μg 6‐AN progressively interfered with subsequent somite growth and cardiovascular function. Addition of nicotinamide (NAM) to the cultures prevented the deleterious effects of the antimetabolite. Following infra‐amniotic injections, 54 to 94% of the implantation sites given 10 to 100 μg 6‐AN exhibited resorbed fetuses or young with abnormal palates, brains, or eyes by day 21 of gestation. The types of defects found in the present study were similar to those observed following maternal treatment with 6‐AN. Direct applications of this teratogen to isolated or in utero rat embryos resulted in decreased growth, increased fetal death, and congenital abnormalities without significant changes in m

ISSN:0040-3709    

DOI:10.1002/tera.1420010111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1968

数据来源: WILEY