A scanning electron microscope study of fetal eyelid closure accelerated by cortisone in SWV/Bc mice

Eyelid closure occurs earlier in SWV/Bc and CBA/J mouse fetuses whose mothers were treated with cortisone on day 14 of gestation than it does in fetuses from untreated mothers. Similar treatment prevents the open-eyes defect of lidgap-Miller mutant mice, but examination by scanning electron microscope (SEM) has shown differences in the periderm of the closing eyelids of the cortisone-treated mutant compared with those of untreated genetically normal fetuses. (Untreated mutant eyelids remain wide open and very abnormal). The present study has examined at the SEM level the accelerated eyelid closure of cortisone-treated normal strain, SWV/Bc, fetuses to investigate whether the differences from normal in the eyelids of treated lidgap-Miller fetuses are part of the mechanism of the cortisone "cure." At the SEM level, cortisone-accelerated eyelid closure of SWV/Bc fetuses is indistinguishable from that in untreated fetuses. This suggests that the early eyelid closure induced by cortisone in normal strain fetuses represents acceleration of the normal coordinated sequence of events that leads to closure, rather than an abnormality that fortuitously leads to closure. The data also indicate that the cellular abnormalities seen previously in treated lidgap-Miller mutant fetuses are a combination of 1) abnormalities due to the mutation that are not completely reversed by cortisone and 2) normal developmental stages that have become concurrent with the cortisone-induced late closure in lidgap-Miller mutant fetuses.     

Alpha-fetoprotein and albumin in experimentally-induced exencephaly in the rat.

Alpha-fetoprotein and albumin were quantified in the sera and amniotic fluids from control, Vitamin A-treated non-exencephalic and Vitamin A-treated exencephalic rat fetuses. Exencephaly was associated with amniotic fluid alpha-fetoprotein concentrations which were significantly elevated over those of Vitamin A-treated non-exencephalic and of untreated fetuses. Amniotic fluid albumin concentrations also were higher in the exencephalic fetuses than in the non-exencephalic fetuses. Serum alpha-fetoprotein and albumin concentrations were lower in the exencephalic than in the non-exencephalic fetuses. The results are cosistent with simple diffusion across a defective barrier as the cause of elevated amniotic fluid alpha-fetoprotein concentrations in the presence of open neural tube defects. This experimental model of neural tube defects result in changes in amniotic fluid alpha-fetoprotein similar to those changes found in human amniotic fluid alpha-fetoprotein concentrations in the presence of neural tube defects.     

Umbilical cord growth in human and rat fetuses: evidence against the "stretch hypothesis"

A total of 103 human fetuses between the 7th and 30th week of gestation were obtained from induced abortion (40 fetuses were normal and 63 were abnormal), and the umbilical cord length (UCL) was measured. The UCL increased almost linearly with gestational age among normal fetuses, contrary to the commonly held tenet that the UCL increases exponentially during the second trimester. When UCLs from the 63 abnormal fetuses were compared with those of normal fetuses, 15 fetuses were found to have short UCL and 10 fetuses to have long UCL. Among the 15 fetuses with short UCL, 6 had early amnion rupture syndrome. An unexpected finding among the 10 with long UCL was that 8 of them had oligohydramnios. It has been suggested that the UCL increases in response to tensile forces placed upon it ("stretch hypothesis"); however, our results are inconsistent with this hypothesis because fetuses with oligohydramnios should be less active and their umbilical cords be subject to less stress. In a separate experiment, we studied the normal development of the UCL in rat fetuses and observed an almost linear increase during the whole gestation similar to that seen in humans. This finding is also inconsistent with the "stretch hypothesis" because amniotic fluid volume decreases significantly from day 19 of gestation to term in rats.     

Hypoglycemia and glycogen deficits in fetuses of hypothyroid pregnant rats.

Maternal hypothyroidism, when induced by surgical thyroidectomy with parathyroid hormone replacement, results in fewer live fetuses and smaller fetuses at the 22nd day of gestation. The hypothyroid mother shows the ability to mobilize adequate amounts of glucose even at the expense of her own reserves but the supply of glucose to the fetus appears to be impaired. These fetuses have subnormal skeletal muscle and liver glycogen and are severely hypoglycemic. The impaired development of these fetuses may result from alterations of either transplacental carbohydrate transport or placentofetal carbohydrate metabolism.     

Evaluation of gestational deficiencies in cloned sheep fetuses and placentae.

Sheep fetal development at 35 days of gestation was examined following natural mating, in vitro production (IVP) of fertilized embryos, or somatic cell nuclear transfer (NT). Five crossbred (Blackface x Black Welsh) and four purebred (Black Welsh) fetuses and their associated placentae produced by natural mating were morphologically normal and consistent with each other. From 10 ewes receiving 21 IVP embryos, 17 fetuses (81%) were recovered, and 15 of these (88%) were normal. The NT fetuses were derived from two Black Welsh fetal fibroblast cell lines (BLW1 and 6). Transfer of 21 BLW1 and 22 BLW6 NT embryos into 12 and 11 ewes, respectively, yielded 7 (33%) and 8 (36%) fetuses, respectively. Only three (43%) BLW1 and two (25%) BLW6 NT fetuses were normal, with the rest being developmentally retarded. The NT fetal and placental deficiencies included liver enlargement, dermal hemorrhaging, and lack of placental vascular development reflected by reduced or absent cotyledonary structures. Fibroblasts isolated from normal and abnormal cloned fetuses did not differ in their karyotype from sexually conceived fetuses or nuclear donor cell lines. Our results demonstrate that within the first quarter of gestation, cloned fetuses are characterized by a high incidence of developmental retardation and placental insufficiency. These deficiencies are not linked to gross defects in chromosome number.     

The effect of androgens upon the differentiation of Cowper and Bartholin glands in rat fetuses (author's transl)]

In the present paper, a study is made of the normal structure shown in Bartholin and Cowper glands of 100 female fetuses and 100 male fetuses of Wistar rats at the end of gestation, with the structure of bulbouretral glands that formed in 70 female fetuses of the same species and period of gestation masculinized by androgens. In relation to the Bartholin glands, whose bilateral sketch is constant in the fetuses, we can affirm that it shows significant differences of structure with regards to the sketch of the Cowper gland. On the opposite, the histologycal details of the latter, are entirely identical to those shown by the bulbouretral glands of the masculinized female fetuses, a fact which permits us to affirm that these are authentic Cowper glands, not only because of their position, but also because of their structure. This morphological data corresponds to a masculinization phenomenon and demonstrates that the Bartholin and Cowper glands are very sensitive to the effect of androgens during gestation.     

Disruption of parental-specific expression of imprinted genes in uniparental fetuses

In mammals, imprinted genes show parental origin-dependent expression based on epigenetic modifications called genomic imprinting (GI), which are established independently during spermatogenesis or oogenesis. Due to GI, uniparental fetuses never develop to term. To determine whether such expression of imprinted genes is maintained in uniparental mouse fetuses, we analyzed the expression of 20 paternally and 11 maternally expressed genes in androgenetic and parthenogenetic fetuses. Four genes of each type were expressed in both groups of fetuses. Furthermore, quantitative analysis showed that expression levels deviated from the presumed levels for some imprinted genes. These results suggest that mechanisms acting in trans between paternal and maternal alleles are involved in the appropriate expression of some imprinted genes.     

Insulin content in the pancreas and blood plasma of decapitated and encephalectomized rat fetuses

Insulin content in the pancreas and blood plasma of encephalectomized, decapitated and intact rat fetuses was measured by radioimmunoassay. Encephalectomy and decapitation of 17.5-day-old fetuses did not produce any significant effect on insulin concentration in the pancreas and blood plasma of 21-day-old fetuses. Injection of glucose to 21-day-old operated fetuses raised insulin secretion, which seems to be related to the potentiating action of maternal and (or) fetal humoral factors. The data obtained indicate that synthesis and basal secretion of insulin to the blood are not disturbed by the lack of the hypothalamohypophyseal control in prenatal rats.     

Comparison of aggregation and injection techniques in producing chimeras with embryonic stem cells in mice

We analyzed embryonic stem cell lines for their capacity to produce aggregation chimeras with diploid or developmentally compromised tetraploid embryos. Descendants of embryonic stem cells which contributed to midgestation fetuses at high levels were capable of supporting fetal development also with tetraploid partners. Different numbers of embryonic stem cells were introduced into diploid and tetraploid morulae as well as into blastocysts by microinjection. There were no differences in the frequency of embryonic stem cell-containing fetuses when comparing aggregation or injection into morulae versus blastocysts. However, the distribution pattern of embryonic stem cell derivatives in chimeric fetuses suggested that pre-compaction embryos are more suitable for generating fetuses with high embryonic stem cell contribution. Injection of embryonic stem cells into tetraploid embryos showed that completely embryonic stem cell-derived fetuses can also be produced by this technique. Totally embryonic stem cell derived fetuses were observed in each group, when embryonic stem cells were injected into diploid embryos. However, the rate of chimeras and chimerism was lower when 1 or 3 embryonic stem cells were used versus 8 or 15 cells. This suggests that the number of embryonic stem cells introduced might play a role in the colonization ability.     

Effects of maternal diabetes on the development of carbohydrate metabolizing enzymes in fetal rat liver

Effects of streptozotocin-induced maternal diabetes on fetal hepatic carbohydrate-metabolizing enzyme development and hormonal status has been explored in the rat. Hepatic glycogen synthase a activity of the normal fetus rose to a maximum at 20 days of gestation, then fell prior to parturition. In fetuses of diabetic mothers, this prepartum decline was curtailed, resulting in enhanced synthase a activity and increased glycogen content in fetal livers at term. Elevation in hepatic synthase a in fetuses of diabetic mothers was due, not to altered interconversion between existing synthase a and b, but to equivalent increases in both forms of the enzyme. Both hepatic and free plasma corticosterone levels were elevated in fetuses of diabetic mothers and may be responsible for the enhanced development of total glycogen synthase observed in these fetuses. In normal fetuses hepatic phosphofructokinase and pyruvate kinase activities also rose to maxima at 20 days, then declined prior to term. In fetuses of diabetic mothers pyruvate kinase activity attained higher than normal maximal levels and phosphofructokinase activity fell more gradually, thus resulting in elevations in both enzyme activities at term. Augmentations in these glycolytic enzymes are compatible with hyperinsulinemia observed in fetuses of diabetic mothers. The following conclusions may be drawn from these findings. During late fetal life developmental patterns of rate-limiting hepatic glycogen-synthesizing and glycolytic enzymes are adapted to glucose utilization. In the normal fetus these patterns reverse at term, thereby promoting glucose mobilization, which prepares the fetus for abrupt deprivation of maternal glucose at birth. Maternal diabetes results in retardation of these reversal processes, presumably due to elevations in fetal glucocorticoid and insulin levels. Glycogenolytic and glucogenic capacities are thereby impaired in these fetuses.     

Influence of the fetal pituitary-adrenal axis on fetal and maternal progesterone and unconjugated oestrogen concentrations in the pig

Fetal and maternal plasma progesterone and unconjugated oestrone and oestradiol-17 beta concentrations were measured in intact pig fetuses and those in which the pituitary had been destroyed. Progesterone concentrations were significantly higher (P less than 0.05) and oestrogen concentrations significantly lower (P less than 0.01) in hypophysectomized fetuses than in intact fetuses. When fetuses in one uterine horn only were hypophysectomized, oestrogen concentrations in the uterine vein draining this horn were lower than those from the contralateral vein. The results indicate that both fetal and maternal oestrogen concentrations are influenced by the fetal pituitary. When dexamethasone was infused (at 27 micrograms/h for 96 h) into 5 chronically-catheterized hypophysectomized fetuses no changes in peripheral fetal progesterone or oestrone were observed.     

Breed differences in biparietal diameters of second trimester Toggenbubrg, Nubian and Angora goat fetuses

Seven purebred Toggenburg fetuses in four does, six purebred Nubian fetuses in four does, and eight Angora fetuses in six does were repeatedly measured using transabdominal real-time ultrasound with a 5 MH(z) linear-array transducer from 40 d to 100 d gestational age (GA) and their biparietal diameters (BPD) were determined. For Toggenburg goats the GA = 27.9 + 1.64 BPD; for Nubian goats the GA = 26.8 + 1.74 BPD; for Angora goats the GA = 28.6 + 1.77 BPD. The breed differences in GA for equal BPD are insignificant at the beginning of the second trimester but are +3 d for Nubian and +6 d for Angora fetuses by the end of the second trimester.     

Glycosaminoglycans in human fetal liver in relation to water and electrolytes

The acidic mucoPolysaccharides secreted into the extracellular sPace are thought to Play many imPortant functions amongst which are binding of water and electrolytes on the Polyanionic glycosaminoglycans. Characteristically these comPonents undergo continuous changes during growth and develoPment of the fetuses. RelationshiPs of the concentrations of glycosaminoglycans to the water and PrinciPal electrolytes at different Periods of gestation were studied in human fetuses. It was found that during growth of the human fetuses there was a Progressive decrease in water, thiocyanate sPace, total sodium content and glycosaminoglycans. However the decrease of glycosaminoglycans was greater than the rate of decrease of the other constituents. Hence mucoPolysaccharides were thought to Play more imPortant roles than just binding of water and cations.     

Changes in the Pattern of Cytokeratin Polypeptides in Epidermis and Hair Follicles During Skin Development in Human Fetuses

Abstract. The cytokeratin polypeptides of microdissected epidermis and hair follicles from human fetuses (from week 10 of pregnancy until birth) have been analysed by two-dimensional gel electrophoresis. Two-layered epidermis in 10-week fetuses contains major amounts of cytokeratin polypeptides typical of simple epithelia (components Nos. 8, 18, and 19 according to Moll et al. [31]). These cytokeratins are gradually reduced in their relative amounts and eventually disappear in the multilayered epidermis of later stages. At advanced stages of development, cytokeratins characteristic of adult epidermis are detected and finally predominate. These include the large and basic epidermal cytokeratin No. 1 (apparent molecular weight 68,000) which is already present in the three-layered epidermis of 13-week fetuses. Hair follicle germ cells of 13-week fetuses differ from fetal epidermal keratinocytes and show a very simple cytokeratin pattern, dominated by only two major polypeptides (Nos. 5 and 17). More developed hair follicles of 20-week fetuses have established a cytokeratin pattern similar to, but not identical with, that of hair follicles from adult skin. Different staining patterns obtained by indirect immunofluorescence microscopy using cytokeratin antibodies with different specificities suggest that, in three-layered epidermis, different cytokeratin patterns might exist in the specific cell layers. Such a differential location might explain the high complexity of polypeptide components found in fetal skin. Possible contributions of peridermal cytokeratins to this complex pattern of fetal epidermis are discussed.     

A rapid method for detecting malformations in rat fetuses

A rapid method for examining rat fetuses is presented. The technique consists of fixing the fetuses in Bouin's solution, serially sectioning the head, neck and lower trunk with a razor blade and doing sagittal sections of the heart after opening the thoracic cavity. Examples of sections from normal 20 day rat fetuses are given as well as some with the following abnormalities: cleft palate produced by chlorcyclizine and eye and heart malformations resulting from anti-adult rat kidney serum.     

Cloned pig fetuses exhibit fatty acid deficiency from impaired placental transport

Cloned pig fetuses produced by somatic cell nuclear transfer show a high incidence of erroneous development in the uteri of surrogate mothers. The mechanisms underlying the abnormal intrauterine development of cloned pig fetuses are poorly understood. This study aimed to explore the potential causes of the aberrant development of cloned pig fetuses. The levels of numerous fatty acids in allantoic ?uid and muscle tissue were lower in cloned pig fetuses than in artificial insemination‐generated pig fetuses, thereby suggesting that cloned pig fetuses underwent fatty acid deficiency. Cloned pig fetuses also displayed trophoblast hypoplasia and a reduced expression of placental fatty acid transport protein 4 (FATP4), which is the predominant FATP family member expressed in porcine placentas. This result suggested that the placental fatty acid transport functions were impaired in cloned pig fetuses, possibly causing fatty acid deficiency in cloned pig fetuses. The present study provides useful information in elucidating the mechanisms underlying the abnormal development of cloned pig fetuses.     

Influence of in vitro systems on embryo survival and fetal development in cattle

In vitro systems are commonly used for the production of bovine embryos. Comparisons between in vivo and in vitro produced embryos illustrate that the morphology of preimplantation-stage embryos differ significantly, the survival of embryos and fetuses is decreased, the size distributions of the populations of conceptuses and fetuses are altered throughout gestation, and placental development is significantly changed. Taken together these findings indicate that exposure to some in vitro environments during the first 7 days of life can profoundly influence fetal and placental development in cattle. An understanding of how in vitro oocyte maturation, in vitro fertilization, and embryo culture systems influence both fetal and placental development should result in systems that consistently produce normal embryos, fetuses, and calves.     

Age-Related and Individual Anatomical Variation in Testicular Topography in Human Fetuses

At present, male infertility remains an urgent medical concern. From year to year, despite advances in methods of diagnosis and treatment, medicine encounters an increasing number of infertile couples with male infertility playing a leading role. Prerequisites for fertility disorders very frequently appear in childhood. Urologists consider cryptorchidism a leading cause of male infertility. The aim of our study was to establish the relationship between testicular descent to the scrotum and the age of the fetus. Material and methods. The study was conducted using 195 specimens of male fetuses aged 4–10 months with 81.0–375.0 mm parietalcoccygeal length (PCL) using the methods of macromicroscopic, conventional, and microslide preparation under control of binocular loupes and morphometry. Results. At the beginning of the fetal period of human ontogenesis (fetuses 81.0–135.0 mm PCL), the right and left testicles are mainly located above the corresponding deep inguinal ring and they are less often located in a region of the iliac fossae. An analysis of topographic and anatomical features of the male reproductive glands in 5-month-old fetuses (136.0–185.0 mm PCL) revealed that the testicles were located within the large pelvis, with the lower end of both the right and left testicles located above the entrance to the deep inguinal ring at a distance that equals the length of the pelvic part of the gubernaculum testis—3.2 ± 0.3 mm (right) and 2.8 ± 0.2 mm (left). In 11 fetuses aged 7 months (231.0–270.0 mm PCL), the lower ends of the testicles and their gubernaculum testis are immersed in the corresponding deep inguinal ring. In eight fetuses, the testicles were within the deep inguinal ring. A combination of many factors contributes to the final migration of a testicle through the inguinal canal into the scrotum (fetuses: 270.0 cm–290.0 mm PCL), including muscle contraction of the anterolateral abdominal wall, an increase in intra-abdominal pressure, contractile capacity of the gubernaculum testis of the testicle, the vaginal process of the peritoneum, and the neuro-muscular system. We believe that the gubernaculum testis is a particularly significant factor in testicular descent to the scrotum. The gubernaculum testis is maximally developed prior to migration of a testicle through the inguinal canal (eighth month of antenatal development), as evidenced by the prevalence of smooth muscle cells over connective tissue elements. An analysis of testicular topography in fetuses aged 9 months (311.0–345.0 mm PCL) revealed that testicles were located in the scrotum in nine fetuses, near the superficial inguinal ring in six fetuses, within the inguinal canal in four cases, and in the deep inguinal ring in one case. In fetuses aged 10 months (346.0–375.0 mm PCL), testicles were located in the scrotum in 13 cases and within the inguinal canal in seven cases. According to our research, the fusion of layers of the vaginal process of the peritoneum occurs in fetuses aged 9–10 months, resulting in the disappearance of the communication of its cavity with the peritoneum. A delay in the fusion of the peritoneal vaginal process layers at the end of the fetal period is an anatomic prerequisite for the occurrence of congenital inguinal-scrotal hernias. Conclusions. It has been found that the rate of testicular descent to the scrotum does not always coincide with the corresponding stage of fetal development. An accelerated development of the gubernaculum testis in fetuses aged 5–8 months is a major factor of heterochronic development of a testicle and subsequent testicular descent into the scrotum.     

Malformations in rat fetuses induced by trypan blue

Malformations of fetuses obtained from Wistar rat dams treated with trypan blue during gestation were studied. Fetuses were examined on day 20 of gestation. One hundred and twenty-seven fetuses showed abnormalities of the external features, skeleton and internal organs, separately or in combination. External malformations were found in 108 fetuses. The most frequent external malformation was anomaly of tail. Spina bifida, club foot, exencephaly and anal atresia were also observed frequently. Skeletal malformations were detected in 48 fetuses. Deformity of vertebrae in the lumbar, sacral and/or caudal regions was found in 46 fetuses. Internal malformations were observed in 27 fetuses. Anomaly of heart and/or great vessels, hydrocephaly and micro- or anophthalmia were observed frequently. About 90% of the fetuses with skeletal malformations also showed some external malformations. In contrast, about 48% of the fetuses with internal malformations also had some external malformations. These results suggest that, for teratological study, internal examination is more important in detecting malformations of fetuses than skeletal examination.     

Aortic Intima-Media Thickness and Aortic Diameter in Small for Gestational Age and Growth Restricted Fetuses

ObjectiveThe objective of this study is to measure aortic intima-media thickness (aIMT) and aortic diameter (AD) in appropriate for gestational age (AGA) fetuses, small for gestational age (SGA) fetuses, and intrauterine growth restricted (IUGR) fetuses.MethodsCase-control study performed between June 2011 and June 2012. Forty-nine AGA fetuses, 40 SGA fetuses, and 35 IUGR fetuses underwent concomitant measurement of aIMT and AD at a mean gestational age of 34.4 weeks.ResultsMedian aIMT was higher in fetuses with IUGR (0.504 mm [95%CI: 0.477-0.530 mm]), than in SGA fetuses (0.466 mm [95% CI: 0.447–0.485 mm]), and AGA fetuses (0.471 mm [95% CI: 0.454-0.488 mm]) (p = 0.023). Mean AD was significantly lower in fetuses with IUGR (4.451 mm [95% CI: 4.258–4.655 mm]), than in AGA fetuses (4.74 mm [95% CI: 4.63-4.843 mm]) (p = 0.028).ConclusionsGrowth restricted fetuses have a thicker aortic wall than AGA and SGA fetuses, which possibly represents preclinical atherosclerosis and a predisposition to later cardiovascular disease.