ISSN:0040-3709    

DOI:10.1002/tera.1420460612

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

年代:1992

数据来源: WILEY

摘要:

AbstractIn developing an avian model for 13‐cis‐retinoic acid (13cisRA) embryopathy, we found 13cisRA induced cardiovascular defects, especially Type I ventricular septal defects (VSDs) (Hart et al.:Teratology41:463–472, '90). As the first step of investigating possible mechanisms, we have examined the light microscopic morphology of RA‐induced cardiovascular defects in chick embryos. Fertilized eggs were injected via yolk sac with 150 μg 13cisRA in dimethylsulfoxide (DMSO), DMSO or mock injection on embryonic day 5 (E5). On E6, E7, or E8, surviving embryos were sacrificed and fixed in 10% formalin. Thoracic blocks were exised, embedded in paraffin and serially sectioned through the heart, base to apex. Slides were stained, screened for tissue orientation, then coded and evaluated without knowledge of treatment group. Examination of serial sections permitted qualitative evaluation of conotruncal ridge volume, mesenchymal organization, necrosis and extent of fusion. Extent of fusion was the only parameter influenced by 13cisRA treatment. On E6, ridge fusion was incomplete in all groups at comparable levels. On E7, ridge fusion in 13cisRA‐treated embryos had not progressed as far proximally as in controls. By E8, there was a significant difference in the extent of fusion between 13cisRA‐treated and non‐RA‐treated groups. We conclude 13cisRA‐induced VSDs resulted from defective conotruncal ridge fusion and that the fusion defects did not result from decreased tissue volume, altered mesenchymal organization or increased necrosis. © 1

ISSN:0040-3709    

DOI:10.1002/tera.1420460602

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

年代:1992

数据来源: WILEY

摘要:

AbstractThese experiments more accurately define the effects of the combination acetazolamide‐amiloride or a single dose of dimethadione (DMO), the active metabolite of trimethadione, on the development of the ureter. When acetazolamide‐amiloride was administered in C57BL/6NCrlBR mice on day 9, 9.5, or 10 of gestation (plug = day 0) a second ureter was formed, anterior to the original ureter, inducing a second kidney. The second ureter then fails to make a connection with the developing bladder and remains attached to the mesonephric duct. The mesonephric duct becomes the vas deferens in the male and deteriorates completely in the female leading to either a resticted ureter or a blocked ureter depending on the sex of the fetus. Administration of a single dose of DMO between gestational day 9 and 10.3 produced both renal agenesis and ureters of varying lengths. Some ureters were of normal length with a tuft of one or two nephrons at their tip, while others were one half or one quarter of their normal length. In some instances the ureter was completely absent. The reason for this strong effect on the ureter is unknown. © 1992 Wiley‐Lis

ISSN:0040-3709    

DOI:10.1002/tera.1420460603

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

年代:1992

数据来源: WILEY

摘要:

AbstractWe describe an epidemiological and clinical study of Clinical Anopthalmia in a population of consecutive live and stillborns enrolled in a hospital based registry of congenital malformations in Northeast Italy during the period from 1981 to 1989; 22 cases were detected among 368,256 births yielding a birth prevalence of 0.60 per 10,000 (95% CI 0.34–0.84); 20 cases were associated with at least one other major malformation. Malformation syndrome, association, or sequence was diagnosed in 13, while a non‐recognizable multiple defect pattern was observed in 7/20 (35%). A chromosomal anomaly was present in eight syndromic cases. No significant trend over time, nor space or time clusters, were detected. As most CAn cases are associated with other anomalies recognizable by ultrasound, a decreasing trend in its prevalence at birth is expected in the future. © 1992 Wiley‐Lis

ISSN:0040-3709    

DOI:10.1002/tera.1420460604

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

年代:1992

数据来源: WILEY

摘要:

AbstractFrom 1983 through 1987, in a California population of 718,208 births, 237 infants were born with a congenital diaphragmatic hernia (CDH), a birth prevalence of 3.30 per 10,000 total births (live births and stillbirths). We proposed that the various types of this defect, characterized by their different pathogeneses, would be reflected in differences in their descriptive epidemiologies. We evaluated various demographic, maternal, and infant characteristics for three major types of defects, the Morgagni hernia, the pars sternalis hernia, and the posterolateral hernia, categorizing the latter type into isolated defect (N = 129), multiple congenital anomalies including nonchromosomal syndromes (N = 86), trisomies (N = 10), and chromosomal anomalies other than trisomies (N = 2). For the posterolateral hernia, we present the distribution of associated anomalies (43%) and specifically of midline defects (19%). Although the number of cases for the Morgagni hernia (N = 5) and the pars sternalis hernia (N = 5) were small, comparisons with the posterolateral hernia suggested lower sex ratios, of borderline significance for the pars sternalis hernia (P<0.09), and higher mean maternal ages for both groups. Within the posterolateral type, we found a significantly higher male to female ratio (M/F = 1.58) only for the isolated subgroup compared to the population (P<0.03), and a borderline significant rural/urban difference in prevalences (2.12 vs. 1.45 per 10,000) (P<0.06). Additionally, the distribution of monthly prevalence rates adjusted for gestational age suggested opposite seasonal trends between the isolated and the other posterolateral hernias; within this latter subgroup the difference between the highest monthly rate (1.68) and the lowest (0.96) was of borderline significance (P<0.09). Our results suggest the need to consider the respective types and subgroups of CDH separately in epidemiologic studies. © 1992 Wiley‐Liss, I

ISSN:0040-3709    

DOI:10.1002/tera.1420460605

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

年代:1992

数据来源: WILEY

摘要:

AbstractWhile there has been a substantial increase in recreational use of cocaine by young adults, conclusive evidence for cocaine teratogenicity in humans in lacking, and even those believing the drug is teratogenic agree that the rates are quite small. While counseling pregnant women on their teratogenic risk, it was our impression that there is an unrealistically high perception of reproductive risk of cocaine. We wished to quantify the perception of teratogenic risk of cocaine by the public, physicians, and by pregnant women who were counseled following gestational exposure to the drug. Women taking cocaine during the first trimester of pregnancy (n = 54), controls with post secondary education (n = 30), and physicians (n = 30) were asked, using a visual analogue scale, to quantify the teratogenic risk of cocaine and the tendency to terminate/contiue the pregnancy after first trimester exposure; in the case of the “public” and physicians this was a hypothetical question. Both physicians and the controls perceived cocaine to be teratogenic (13.4 ± 11% risk of major malformations by physicians, and 56.5 ± 22.8% by the “public”). The controls believed cocaine to be as hazardous as thalidomide (57.2 ± 25.6% risk for thalidomide). Asked whether they would wish to terminate such pregnancy in their family, most physicians (56%) and the controls (70%) had a greater than 50% tendency to terminate. In pregnant patients attending Motherisk, the counseling process resulted in a significant decrease in risk perception of cocaine (from 37.5 ± 20.5% to 17.6 ± 14.2%P<0.0005), and a similar decrease in tendency to terminate pregnancy [from 21/54 (38%) with 50% tendency to terminate to 11 (20%);P= 0.0014]. Postnatal follow‐up revealed that eight women terminated pregnancy while the rest had morphologically and developmentally normal babies. An unrealistically high perception of teratogenic risk of cocaine exists among the controls, physicians, and pregnant women. Physicians' erroneous perception may lead them to offer women unjustified terminations of pregnancy after first trimester exposure to cocaine. Counseling these women during the first trimester is effective in preventing termination of many otherwise wanted pregnancies. © 1992

ISSN:0040-3709    

DOI:10.1002/tera.1420460606

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe problem of developing biologically‐based dose–response models is addressed for predicting the prevalence of birth defects at low doses of toxic chemicals administered during pregnancy. To illustrate the process of incorporating biological information, a model is postulated to predict the prevalence of cleft palate for a chemical that reduces embryonic/fetal growth, which results in inadequate palatel cells for closure. Experimental bioassay data examining the prevalence of cleft palate in mice exposed to the herbicide 2,4,5‐T are used to illustrate the process. With the limited data available, it is necessary to assume a model for cell growth and the relationship between the cell growth rate parameter and dose of 2,4,5‐T. Also, a relationship between cleft palate prevalence and growth is assumed and then checked with experimental data. The purpose for the paper is not to provide a universal biologically based dose–response model for cleft palate, but rather to demonstrate the extent, and type of information and data required. It remains to be seen if the form of the model is appropriate for chemicals that primarily produce embryo/fetal malformations or death via reduced or delayed cellular growth. © 1992 Wiley

ISSN:0040-3709    

DOI:10.1002/tera.1420460607

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe lenses and head mesenchyme of two 11‐gestational day trisomy 1 mouse embryos and a normal littermate were examined using transmission electron microscopy (TEM). One trisomic embryo had a small lens with a lens stalk; the other was aphakic. The resolution available with TEM allowed detailed evaluation of cell organelles, spatial relationships and the intra‐ and extracellular structural environment of the lens and head mesenchyme in normal and aneuploid embryos. Differences in fine structure between normal and trisomic lenses included (1) type of epithelium, (2) size of intercellular lacunae, and (3) activity of Golgi complexes. Differences in mesenchyme included (1) the number and size of cytoplasmic extensions, (2) shape of the cells, and (3) reduced endotheliomesenchymal interactions. © 1992 Wiley‐Lis

ISSN:0040-3709    

DOI:10.1002/tera.1420460608

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

年代:1992

数据来源: WILEY

摘要:

AbstractHomozygous Splotch mutant mice (Sp/Sp) die on day 14 of gestation with neural tube defects, curly tail, and malformations of neural crest derivatives. Sp1Hmice, which have a radiation‐induced allele of Splotch with a similar phenotype, were used for this study. The neural tube defects are always located in the lumbosacral region and in 50% of the cases also in the region of the hindbrain. In this report, rare cases of neural tube defects and tail defects among the offspring of crosses between Splotch (Sp1H) heterozygotes are presented, which are not associated with a neural crest defect. This suggests that the development of the neural tube and neural crest defects in this mutant is caused by independent mechanisms or is dependent on the dosage of the mutant gene, with different thresholds being pathogenetic in the neural tube and neural crest, respectively. © 1992 Wiley‐Liss,

ISSN:0040-3709    

DOI:10.1002/tera.1420460609

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

年代:1992

数据来源: WILEY

摘要:

AbstractThis study reports data on craniometric measurements in the X‐linked hypophosphatemic (Hyp) mouse on two different genetic backgrounds: C57BL/6J and B6C3H. Heads of normal females “+/+,” normal males “+/Y,” heterozygous mutant females “Hyp/+,” and hemizygous mutant males “Hyp/Y” for each genetic background were examined. Data were collected via skull measurements.On a C57BL/6J background, the neurocranium of mutants “Hyp/+” and “Hyp/Y” was shorter and slightly higher than in normal counterparts.On a B6C3H background, mutant mice “Hyp/+” and “Hyp/Y” were shorter in neurocranial length than in normal counterparts. Viscerocranial height was larger in “Hyp/Y” than in normal counterparts. No differences in neurocranial and mandibular height were found.Mutant mice on a C57BL/6J background were compared to mutant mice on a B6C3H background.No differences in neurocranial length were found. Cranial length was shorter in “Hyp/Y” on C57BL/6J than in “Hyp/+” on B6C3H. Facial length parameters were shorter in “Hyp/Y” on C57BL/6J than in “Hyp/Y” and “Hyp/+” mutant mice on B6C3H. Mandibular length was shorter in “Hyp/Y” on C57BL/6J than in “Hyp/+” on C57BL/6J and both mutant mice (“Hyp/Y” and “Hyp/+”) on a B6C3H background. The results of this study indicate that craniofacial growth is less affected in mutant mice on a B6C3H genetic background tha

ISSN:0040-3709    

DOI:10.1002/tera.1420460610

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

年代:1992

数据来源: WILEY