ISSN:0040-3709    

DOI:10.1002/tera.1420020402

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

年代:1969

数据来源: WILEY

摘要:

AbstractThis report is concerned with some biochemical effects of ovariectomy and hypervitaminosis A on cell organelles, with particular emphasis on the lysosomes, of embryos, yolk sacs, and placental labyrinths of 13‐day pregnant rats. The two parameters considered were lysosomal stability and the distribution of enzymes in fractions obtained by differential centrifugation. Lysosomal stability was determined by measuring (1) the amount of “free” enzyme activity, i.e., the amount of enzyme in the cytoplasmic extracts of the three tissues measured in the presence of isotonic sucrose and (2) the amount of “nonsedimentable” enzyme. Excess vitamin A produced no change in the latency of acid phosphatase or β‐glucuronidase in any of the tissues when compared with controls. Following ovariectomy there was marked labilization of both enzymes in embryos, increased labilization of β‐glucuronidase in placentas, and little change in yolk sacs.The distributions of the lysosomal enzymes in control fractions were not the same in the three tissues, indicating differences in size, shape, and/or density of the lysosomes. There was no change in the distribution of reference enzymes after hypervitaminosis A. Ovariectomy produced increased solubilization of β‐glucuronidase in the three tissues and a lesser increase in soluble acid phosphatase in embryos, indicating lack of uniformit

ISSN:0040-3709    

DOI:10.1002/tera.1420020403

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

年代:1969

数据来源: WILEY

摘要:

AbstractThis report is concerned primarily with the chronological relations among stages of palatal closure, changes in facial profile, and the sex of a select group of human embryos representing the critical period of palate development. Histological serial sections of 40 human embryos ranging in age from 6 to 9 weeks and free from gross defects were studied using light microscopy and graphic reconstructions. Maxillary prognathism usually occurred concomitantly with vertically oriented palatal shelves. As the shelves progressively assumed a horizontal position prior to palatal closure, a profile reversal occurred, i.e., the lower jaw became prognathic. Both profile reversal and reorientation of the palatal shelves occurred earlier in males (seventh week) than females (eighth week). These patterns suggest a sexual dimorphism in which the palatal shelves in females are apart and vertical for a relatively longer time than in males. Also, the concordance between palatal‐shelf elevation and mandibular prognathism suggests that the forward repositioning of the lower jaw may contribute to the removal of the tongue from between the palatal shelve

ISSN:0040-3709    

DOI:10.1002/tera.1420020404

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

年代:1969

数据来源: WILEY

摘要:

AbstractDiphenylhydantoin was teratogenic and caused prenatal death in Swiss‐Webster mice. Most deaths resulted after single treatment on days 10, 11, 12, 14, and 15. Fetal body weight was significantly reduced in a dose‐related manner after single treatment on days 9 to 15. Single injections of diphenylhydantoin produced open eye, ectrodactyly, cleft lip, cleft palate, hydronephrosis, and internal hydrocephalus. Skeletal defects noted were incomplete ossification of sternebrae or cervical centra, unfused sternebrae, and fused vertebrae. Long bones were shortened in a day‐ and dosage‐dependent fashion. Mortality, teratogenesis, and effect on fetal growth were day‐ and dosage‐dependent as was the spectrum of anomali

ISSN:0040-3709    

DOI:10.1002/tera.1420020405

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

年代:1969

数据来源: WILEY

摘要:

AbstractHyperthermia was induced in guinea pigs for 1 hour daily on eight, four, or two occasions on days 4–32 of gestation. Maternal core temperature was elevated for about 90 minutes during and after each exposure and the mean maximum elevation was approximately 3.6°C above normal. There was little effect on gestation or fetal development of treatment during days 4–11 of pregnancy. Fetal resorption occurred following exposure on days 11–15 and abortion was common following exposure on days 15–18. Developmental abnormalities were noted in newborn offspring following heat treatment during days 11–32 and were most common after exposure on days 18–25. Microphthalmia and coloboma followed exposure during the earlier part of this period and micrencephaly during days 15–27. Cataract, exomphalos, talipes, abnormalities of bone development, incisor teeth, and digits of the forelimbs, and renal agenesis occurred in various frequencies particularly following exposure on days 18–25. Amyoplasia affecting muscles of the neck, forelimbs, thorax, and abdomen, which was associated with reduced size of the cervical and thoracic spinal cord, followed exposure on days 26–31. The techniques used to induce hyperthermia are described and possible adverse effects of hyperthermia on fetal develop

ISSN:0040-3709    

DOI:10.1002/tera.1420020406

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

年代:1969

数据来源: WILEY

摘要:

AbstractHyperthermia was induced in pregnant guinea pigs for 1 hour on 2, 4, or 8 consecutive days between days 4 and 67 of gestation. Mean newborn brainweight was reduced substantially and incidence of micrencephaly increased following hyperthermia on 4 or 8 successive days during days 15 to 32, and apparently to a lesser degree following exposure on days 39 to 46, and 53 to 60 of gestation. Maternal hyperthermia at other than these periods was associated with little or no reduction in mean brainweight or increase in incidence of micrencephaly. Following hyperthermia on 2 successive days during days 14 to 31 of gestation the incidence of micrencephaly was increased and mean brainweight decreased in offspring from females heat stressed on days 16–17, 20–21, 22–23, and 24–25. The effects of hyperthermia on brain growth were most marked on days 20–21 or 22–23. Following 1 hour of maternal heat stress on day 21 of gestation, brainweight of newborn animals was reduced if maternal body temperature was elevated more than 2.5°C above normal. For each 1°C elevation in body temperature above this level brainweight was reduced by approximately 8.4% compared with c

ISSN:0040-3709    

DOI:10.1002/tera.1420020407

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

年代:1969

数据来源: WILEY

摘要:

AbstractEye defects including corneal capacity, microphthalmia, cataract, and anophthalmia occur spontaneously in C57BL mice. Breeding experiments with substrain C57BL/10ChPr described in the present report indicated that the probability of inclusion of animals with eye defects in litters subsequent to the first is influenced by litter spacing, litter size, and suckling of offspring. Second and third litters were as likely to include progeny with eye defects as were first litters if they resulted from matings taking place after weaning of the previous litter or if the mother was prevented from suckling her previous litter. If the gestation period overlapped with suckling of young from a previous litter the resulting litter contained fewer offspring and animals with eye defects were less likely to be included. Reduction in litter size appeared to result from embryonic losses prior to the time of implantation. The prevalence of overlap between gestation and suckling of young, in matings used for stock maintenance, led to an apparent decline with increasing litter rank in the frequency of litters that included progeny with eye defects.

ISSN:0040-3709    

DOI:10.1002/tera.1420020408

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

年代:1969

数据来源: WILEY

摘要:

AbstractTen mg/kg 5‐fluoro‐2‐deoxycytidine (FCdR) was given intraperitoneally to pregnant mice of the inbred C57BL/6JHanFfm and C57BL/10JFfm‐ +ldstrains once at successive stages of organogenesis. Near‐term fetuses were analyzed for gross and skeletal malformations. The following observations were made. (1) The critical period for eye defects occurred at stages IV–X with a maximum response at stages VIII:18 for C57BL/10− +ldand IX for C57BL/6. Females were more often affected than males, and right eyes more often than left. (2) The critical period for the vertebral column was at stages VI–XII with maximum response at stages IX–XI for vertebral bodies and neural arches and IX for ribs. (3) Limb primordia reacted at stages VIII:18–XII, with two peaks of maximum response at stages IX and XI. (4) Skull primordia reacted at stages VI–IX with no clear peak of maximum response. The types of malformations were described. They were found to be nonspecific for FCdR. Strain differences regarding times of maximum response were explained by the different rates of intrauterine development. Concerning the sporadic malformations seen in controls and at a higher rate and severity in the experimental series, it was concluded that FCdR changed the threshold for these genetical

ISSN:0040-3709    

DOI:10.1002/tera.1420020409

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

年代:1969

数据来源: WILEY

摘要:

AbstractEight human embryos of Streeter's Horizons XIV to XXI were examined with respect to variations in caudal neural tube development after closure of the posterior neuropore in Horizon XII. A major aspect of this development appears to be a process of “canalization” (accessory lumens coalescing from the differentiating caudal neural cell mass), which corresponds to such occurrences in the chick and rat. Some degree of obliteration of the central canal was found in four embryos.The relation of these observations to clinical entities is discussed. There is suggestive evidence that open lesions of the spine may be associated with failure of closure of the posterior neuropore. In contrast, normal‐skin covered lesions probably arise from neural tube formed from the differentiating caudal cell mass after Horizon XII. This hypothesis could explain the distribution of lesions seen in newborn chi

ISSN:0040-3709    

DOI:10.1002/tera.1420020410

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

年代:1969

数据来源: WILEY

摘要:

AbstractFemale mice of the inbred C57BL/6 strain were crossed to males of the A/J strain. F1females were backcrossed to A/J males, the backcross females were crossed to A/J males, and so on for six backcross generations. In each generation a reciprocal backcross was obtained by crossing the hybrid males with A/J females. The following conclusions were drawn: (1) Spontaneous resorption in the C57BL/6 strain is determined in part by genes, recessive to their alleles in the A/J strain, which act in the mother, rather than the fetus. (2) The predisposition to spontaneous cleft lip in the A/J strain shows multifactorial inheritance. In the backcrosses, where the picture is not complicated by the maternal effect, the frequency of cleft lip reached the A/J level only in the sixth backcross. (3) In each backcross generation (hybrid mother) the cleft lip frequency was lower than in the genetically similar reciprocal backcross (A/J mother); thus the A/J mother contributes to the fetal susceptibility to cleft lip, either by providing an appropriate uterine environment or by not providing a factor, present in the C57BL strain, that decreases susceptibility to cleft lip.

ISSN:0040-3709    

DOI:10.1002/tera.1420020411

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

年代:1969

数据来源: WILEY