ISSN:0040-3709    

DOI:10.1002/tera.1420030102

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

年代:1970

数据来源: WILEY

摘要:

AbstractThe inheritance and description of a lethal condition involving sireniform abnormalities in mice are reported. Symmelia was produced by homozygosity for an incomplete recessive gene provisionally called siren (symbolsrn). Sirens were apodal, monopodal, or dipodal. with the ischia present as a vestigial structure or missing. Femora, when present, were medially placed and usually fused. Pubes and tibiae were abnormal in some cases, and fibulae usually were. Visceral defects included absent or abnormal kidneys and adrenals, and blind or undeveloped intestines.

ISSN:0040-3709    

DOI:10.1002/tera.1420030103

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

年代:1970

数据来源: WILEY

摘要:

AbstractDay‐15 rat uteri were exteriorized under ether anesthesia and 100 μg 6‐AN + 500 μg oxidized (NAD;NADP) or reduced (NADH;NADPH) coenzyme; 500 μg adenosine triphosphate (ATP); or 100 μg nicotinamide (NAM) were injected into amniotic cavities in one horn. Embryos in the opposite horn served as injection controls. Mothers were closed and returned to their stock diet until autopsy on day 21 of gestation (day 0 = day of finding spermatozoa); fetuses were weighed, fixed, and examined for congenital abnormalities. Coenzymes, ATP, and NAM appeared to correct fetal and placental weight loss observed in 6‐AN‐treated fetuses. Vitamin and coenzyme therapy but not ATP treatment reduced the frequency and severity of brain and skeletal malformations to the double puncture, solvent control value. The data suggest that malformation and mortality may involve separate

ISSN:0040-3709    

DOI:10.1002/tera.1420030104

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

年代:1970

数据来源: WILEY

摘要:

AbstractBefore the palate begins to close in mouse and rat embryos the cranial base in flexed in the area of the craniopharyngeal canal. As the process of palate closure progresses there is a gradual reduction in the flexure of the cranial base until finally, when the palatine processes are horizontal, the cranial base is almost straight. Rapid growth and straightening of the cranial base might play a role in palate closure by providing the “internal shelf force.” This hypothesis can be demonstrated by means of a mechanical model. The model consists of a thin sheet of plastic cut in the shape of a sagittal view of a vertical shelf and a piece of string attached to the convex border of the model shelf to represent the cranial base (in its flexed position). When the string is pulled, and the angulation of the “cranial base” is reduced to a straight line, the distal part of the model palatine process rotates to a position perpendicular to the proximal or attached part of the shelf, in a manner similar to that of the palatine processes in the

ISSN:0040-3709    

DOI:10.1002/tera.1420030105

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

年代:1970

数据来源: WILEY

摘要:

AbstractGroups of 16 pregnant rats per treatment were fed ad libitum a basal diet containing 0, 0.3, 0.5, or 0.7% mimosine or allowed a restricted intake of the diet with no mimosine until killed on day 20 of gestation.Incremental increases of mimosine caused significant (P<0.01) decreases in daily feed consumption, weight gain per unit of food, and total weight gain. A significant (P<0.01) increase in fetal resorption, but no difference in mean conceptuses per litter, was associated with 0.7% mimosine. Fetal deformities due to constriction of localized parts occurred in litters from females fed 0.5 and 0.7% mimosine. Deformities were associated with perforations in the uterus between placental attachments with partial protrusion of fetuses through the uterus.Most sacral vertebrae were missing in fetuses of females fed 0.7% mimosine and of restricted intake controls. There were no differences in hematocrit values due to treatment.

ISSN:0040-3709    

DOI:10.1002/tera.1420030106

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

年代:1970

数据来源: WILEY

摘要:

AbstractPregnant rats were injected intraperitoneally with large doses of insulin. Controls were given intraperitoneal saline. Rats allowed food ad libitum maintained lowered blood‐sugar levels and did not go into hypoglycemic shock; fasted rats died. Fifty‐four rats produced 532 fetuses, gross and microscopic examination of which revealed no skeletal or other abnormalities. Some implications are discus

ISSN:0040-3709    

DOI:10.1002/tera.1420030107

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

年代:1970

数据来源: WILEY

摘要:

AbstractActinomycin D (act D) was teratogenic to Syrian hamsters. The most effective dosage, 200 μg/kg of body weight, produced malformations when injected on day 4, 6, 8 or 10 of gestation. 100 μg/kg produced malformations only after injections on day 6 or 8. 300 μg/kg was strongly embryolethal, but some malformed fetuses were found among live survivors. 400 μg/kg caused 100% maternal lethality. The teratogenicity and fetal and maternal lethality were reduced when act D was mixed with nucleic acids. DNA was more potent than RNA in preventing toxic effects of act D. The embryolethal effect of act D was also diminished by treatment with a combination of 4 mg progesterone and 1 μg of estrone, although maternal lethality and teratogenicity were not preve

ISSN:0040-3709    

DOI:10.1002/tera.1420030108

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

年代:1970

数据来源: WILEY

摘要:

AbstractThe sequence of events leading to the closure of the neural tube has been investigated in hamster embryos. This consisted of: (1) approach and fusion of the neural folds at the level of the presumptive neural‐crest cells; (2) active proliferation of the neural‐crest cells at the area of fusion and formation of a distinct wedge by them; (3) fusion and closure of the surface ectoderm; (4) reduction of the number of neural‐crest wedge cells due to their active migration from it; (5) fusion of the neurectoderm beginning at the ependymal surface, progressing dorsally until the neural tube was completely closed; and (6) fusion and closure of the mesoderm between the surface ectoderm and the closed neural tube. The time required to complete this sequence of events, the amount of embryonic tissue involved in it at a given time, and the number of neural‐crest cells formed at the area of fusion varied from one region of the embryo to another. It is postulated that the mesoderm appeared to play a double role in the process of closure—a direct one late in the closure process (see 6) and an indirect one, perhaps as a buttress supporting the other cellular elements during the entire closur

ISSN:0040-3709    

DOI:10.1002/tera.1420030109

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

年代:1970

数据来源: WILEY

摘要:

AbstractA/J mice were subjected to restraint and/or food and water deprivation for 24 or 48 hours beginning on day 14 of pregnancy. The 48‐hour treatment sharply increased the cleft palate and resorption rates. The data strongly suggest that restraint can cause cleft palate if imposed for an extended period of tim

ISSN:0040-3709    

DOI:10.1002/tera.1420030110

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

年代:1970

数据来源: WILEY

摘要:

AbstractSequential litters and generations of A/He mice were given repeated injections of actinomycin D or urethan to study effects on fertility, embryotoxicity, teratogenicity, and carcinogenicity. The drugs were given every other day throughout pregnancy. Seven weeks separated each mating and course of treatment. Both drugs had a deleterious effect on fetal development dependent on dosage and litter series. The largest dosages blocked development completely; the effect of 50 μg/kg actinomycin D lasted through the second mating period. The number of offspring relative to controls was also decreased with smaller dosages. Drug toxicity increased with successive matings. In three consecutive generations commencing with females obtained from the lowest treatment regimen a response was observed similar to that seen in offspring obtained by repeated treatment of the same females. Actinomycin D was less carcinogenic than urethan; an increase in the number of lung tumors was found only in the females used for breeding. Compared to the control group, both breeders and offspring exposed transplacentally had an increased incidence of tumors following urethan administration. Malformations occurred only after urethan treatment

ISSN:0040-3709    

DOI:10.1002/tera.1420030111

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

年代:1970

数据来源: WILEY