Mid-gestational Age Research Articles

Primitive Erythropoiesis in the Mouse is Independent of DOT1L Methyltransferase Activity.

DOT1-like (DOT1L) histone methyltransferase is essential for mammalian erythropoiesis. Loss of DOT1L in knockout (Dot1l-KO) mouse embryos resulted in lethal anemia at midgestational age. The only recognized molecular function of DOT1L is its methylation of histone H3 lysine 79 (H3K79). We generated a Dot1l methyltransferase mutant (Dot1l-MM) mouse model to determine the role of DOT1L methyltransferase activity in early embryonic hematopoiesis. Dot1l-MM embryos failed to survive beyond embryonic day 13.5 (E13.5), similarly to Dot1l-KO mice. However, when examined at E10.5, Dot1l-MM embryos did not exhibit overt anemia like the Dot1l-KO. Vascularity and the presence of red blood cells in the Dot1l-MM yolk sacs as well as in the AGM region of Dot1l-MM embryos appeared to be similar to that of wildtype. In ex vivo cultures of yolk sac cells, Dot1l-MM primitive erythroblasts formed colonies comparable to those of the wildtype. Although ex vivo cultures of Dot1l-MM definitive erythroblasts formed relatively smaller colonies, inhibition of DOT1L methyltransferase activity in vivo by administration of EPZ-5676 minimally affected the erythropoiesis. Our results indicate that early embryonic erythropoiesis in mammals requires a DOT1L function that is independent of its intrinsic methyltransferase activity.

Radial glomerular count- An assessment of human nephrogenesis

Introduction: The important reason for progression of various glomerulopathies is variable Radial glomerular count [RGC]. There are few studies on the radial glomerular count. Therefore, we conduct this study, with an aim to contribute the knowledge of the human developing kidney by counting radial glomerular number. Materials and Methods: Thirty normal human fetuses of midgestational period [14 to 28 weeks] were selected for the study. The fetus should not have any congenital anomaly. The fetal kidney tissue slides were prepared and stained in hematoxylin and eosin. Then numbers of glomerular generations were counted and correlate the data with the different gestational groups. Results: The results showed that the average RGC is gradually increasing from 4 to 15 counts in mid gestational age. The results suggest significant statistical correlation between the period of gestation and the number of glomerular generations (Correlation coefficient value R2= 0.99). The fetal kidney weight and the number of glomerular generations in respective gestational age also shows definite statistical correlations. Conclusion: The present study concluded that gradually increasing average RGC can express human fetal kidney growth in intrauterine life. The histomorphologic assessment of RGC can be used as relatively better method of estimating gestational age. The observed growth tendencies of fetal glomerulus in human fetal life by RGC could be useful to assess the kidney maturity in the future. Keywords: Glomerulopathies, RGC.

Utility of indirect sonographic signs (including cavum septum pellucidum ratio) in midgestational screening for partial agenesis of corpus callosum.

This study was undertaken to evaluate the performance of indirect sonographic signs in detecting partial agenesis of the corpus callosum (pACC) at midgestation, focusing on the cavum septum pellucidum (CSP) ratio. A retrospective case-controlled study of singleton pregnancies was conducted, examining fetuses diagnosed with isolated pACC and normal controls. At midgestational age, fetal head volumes were imaged with 3D US and stored for the evaluation of indirect sonographic findings in axial planes. Fifteen normal and 15 abnormal fetuses (with pACC) were analyzed. Based on a CSP ratio < 1.5, detection of pACC increased from 66.7% (10/15) to 80% (12/15). All indirect signs proved highly suspicious for pACC (risk ratios > 1). Use of indirect sonographic signs to screen for pACC at midgestation is challenging. However, a low CSP ratio may improve the detection rate, serving as a new indirect sign.

Application of MRI in prenatal diagnosis of congenital heart disease

Congenital heart disease(CHD)is one of the main causes of newborn death, which makes the prenatal diagnosis of CHD the hot spot of perinatology.Fetal echocardiography has high sensitivity in diagnosing fetal CHD in mid-gestational age of pregnancy, and is considered world-widely as the gold standard.Rapid advance has been achieved for the past decades in the technology of fetal cardiac magnetic resonance imaging(MRI). The advantages of fetal cardiac MRI including broad vision of interest and good reproducibility could make up for the deficiency of fetal echocardiography.However, some technical problems significantly limit the clinical application of it.Nowadays, fetal cardiac MRI has been utilized as a supplementary method in prenatal diagnosis of fetal CHD.This article reviews the application, advantages and limitations of fetal cardiac MRI in fetal CHD diagnosis. Key words: Fetal congenital heart disease; Fetal cardiac MRI

1331 Percutaneous Transhepatic Ultrasound-Guided Cardiac Catheterization in a Fetal Lamb Model

BackgroundFetal cardiac intervention may alter the progression of cardiac conditions. Fetal heart access by direct puncture of the fetal heart under ultrasound guidance has been established, but with considerable technical...

Reserve Cells in Human Uterine Cervical Epithelium Are Derived from Müllerian Epithelium at Midgestational Age

The role of endocervical reserve cells in squamous metaplasia and neoplasia is still debated. Their origin in the cervix is open to speculation and it is unclear how they are targeted during carcinogenesis. To further understand the primary characteristics of reserve cells, we phenotyped them in the developing human cervix. In 13 perinatal autopsies of fetuses between 16 and 40 weeks of gestation, the human fetal cervix was evaluated in serial sections. Immunostaining comprised a panel of antibodies for cytokeratins, p63, and bcl-2; then, the sections were stained with Alcian blue and periodic acid-Schiff before and after diastase treatment. Reserve cells are first identified at approximately 20 weeks of gestation. They are first noted under müllerian-type columnar cells lining the developing uterine cavity. There is considerable overlap in the expression profiles of müllerian cells and reserve cells for p63, bcl-2, and cytokeratins 5, 8, and 18 at this stage of development, with increasing gestational age expression localized to respective cell compartments. Eventually, the phenotype of these cells correspond fully with that described for adult reserve cells and endocervical cells. Müllerian epithelial cells are the stem cell for endocervical reserve cells and endocervical columnar cells. They have the capacity to transform into both endocervical columnar and squamous-type epithelium in the endocervix during early cervical development.

Developmental expression of canalicular transporter genes in human liver

BSEP, MRP2, and MDR3 are major hepatic canalicular transporters mediating bile secretion. Their expression in human liver during development has not been reported. Human liver samples from fetus at gestational age 14-20 weeks, adult livers and liver samples of infants with biliary atresia were tested for mRNA expression of BSEP, MDR3, MRP2, NTCP, FIC1, and FXR genes by using real-time RT-PCR. Immunohistochemical staining of BSEP, MDR3, and MRP2 were performed on fetal and adult livers. All the genes tested were expressed at mid-gestational age. MDR3 and NTCP showed significant lower levels in fetal livers compared to adults. In patients with biliary atresia, all the genes tested showed higher mean expression levels than adults except for NTCP, but not statistically significant. The immunohistochemical staining of MRP2 in fetal liver was canalicular, BSEP showed both intracellular and canalicular staining, and MDR3 staining was faint, only occasional canalicular pattern could be seen. The major canalicular transporter genes are expressed at mid-gestational stage during human fetal development, but are different in expression level and targeting pattern, indicating differential regulation and maturation.

Immunohistochemical and Ultrastructural Characterization of Cortical Plate Microvasculature in the Human Fetus Telencephalon

The blood–brain barrier (BBB) differentiation was investigated by immunohistochemistry and electron microscopy in the radial microvasculature of the telencephalon cortical plate (CP) of 12- and 18-week human fetuses. The BBB-specific glucose transporter isoform 1 (GLUT1) is expressed in both stages, with a main localization on the ablumenal and lateral plasma membranes of the endothelial cells. The endothelial cells are welded by short junctions with fusion points of the plasma membranes at 12 weeks and by extensive tight junctions at 18 weeks. The basal lamina is discontinuous beneath the endothelium–pericyte layer at 12 weeks and splits into two continuous layers circumscribing the pericytes in the later stage. The expression of laminin, a basal lamina glycoprotein, is continuous already at 12 weeks. The CP microvessels are tightly surrounded by processes of glial cells. Immunodetection of the cytoskeletal filament proteins, vimentin (VIM), and glial fibrillary acidic protein (GFAP), demonstrates that at 12 weeks the perivascular glial processes are mostly represented by VIM-stained fibers of the radial glia. At 18 weeks, GFAP-stained radial glia fibers, processes of VIM-stained astroblasts, and GFAP-positive astrocytes also build the perivascular envelopes. The results indicate that the vessel differentiation is already under way in the human CP at the midgestational age and entails the establishment of some barrier devices. The early relationship between perivascular glia coverage formation and endothelial barrier maturation suggests that also immature astroglial cells are involved in the setting up of the BBB.

Tissue-specific expression of inhibin/activin subunit and follistatin mRNAs in mid- to late-gestational age human fetal testis and epididymis.

Inhibin/activin subunit (alpha, beta A, and beta B) immunoreactive protein localization patterns and cell type specific inhibin alpha-subunit mRNA expression have been examined in early- to midgestational age human fetal testes. The scarcity of available third trimester human fetal tissue has, however prevented a complete examination throughout the gestational period and the cell specific expression of follistatin and beta A- and beta B-subunit mRNAs are currently unknown at any gestational age. In the present study, this gap is filled and report mRNA expression patterns of inhibin/activin subunits in mid- and late-gestational age (21-33 wk) human fetal testes and testicular duct system. We also report the first examination of follistatin mRNA signals in the human fetal gonad is also resent in both tubular and interstitial cells, and beta B-subunit mRNA is expressed in seminiferous tubules, in mid- and late-gestational age human fetal testes. Inhibin/activin beta A-subunit mRNA was detected in the interstitial cells of remarkably well preserved mid (21 and 22 wk) and late (29 wk) gestational age testes, and is the only activin-system factor mRNA also expressed in tissue of the duct system of the testis (smooth muscle cells of the epididymis). Follistatin mRNA signal was equal to background levels in testicular and duct tissues at all ages examined. These cell specific expression patterns suggest prominent and possibly differential roles for the inhibins and activins, unopposed by gonadal follistatin, in the human fetal male reproductive system.

Distribution and Function of the Adrenergic and Cholinergic Receptors in the Fetal Calf Bladder During Mid-Gestational Age

Distribution and Function of the Adrenergic and Cholinergic Receptors in the Fetal Calf Bladder During Mid-Gestational Age

Differential expression of leukocyte common antigen in human fetal lymphoid organs.

To investigate the differential expression of various types of leukocyte common antigen (LCA) isoforms during development, we analyzed human fetal lymphoid organs, including the thymus, liver, spleen, and bone marrow from 14 weeks to 29 weeks of gestational age by immunohistochemical and flow cytometric methods. In fetal thymus, over 90% of thymocytes throughout the entire fetal life expressed CD45RO and CD45RB, while CD45RA was expressed only in less than 5% of thymocytes. This expression pattern of LCA isoforms was established by a gestational age of 14 weeks or earlier, and persisted throughout the fetal period. The tissue distribution was different from each isoform; CD45RO-positive thymocytes were found in both the cortex and medulla at the 14th week with low intensity, but was localized in the cortex with increasing fetal age. CD45RB-positive thymocytes distributed mainly in the medulla from early gestational age. Among extrathymic lymphoid organs, a small portion of lymphoid cells expressing leukocyte common antigens appeared first in the liver at 10-12 weeks of gestational age and was followed by a small number in the spleen and bone marrow by 13-15 weeks. All lymphoid cells in these extrathymic lymphoid organs at this stage were CD19+ B cells. The number of these CD19+ cells increased abruptly during the early period of mid-gestational age. The pattern of tissue distribution of each LCA isoform in the fetal liver and spleen correlated well with the patterns of quantitative analysis by flow cytometry. In summary we found that different LCA isoforms expressed in cell-type-specific pattern and showed different tissue distribution during the period of fetal development, and that LCA was the earliest antigen expressed by lymphocytes in the thymus and extrathymic lymphoid organs in our series.

Electron microscopy of rabbit retinal transplants

The development of transplants of embryonic rabbit retinal tissue to adult rabbit eyes was examined in the electron microscope. Neuroretinas from mid gestational age (E14-E20) were transplanted into ten adult hosts and allowed to develop subretinally in the host eye for one to 13 weeks. The transplanted immature retinal cells continued to develop after transplantation, differentiating into different cell types. They developed several of the normal ultrastructural cell characteristics, which made it possible to identify many of the normal retinal cell types.After one week immature rosettes were seen, with zonulae adherentes between the photoreceptor cells and Muller cells, forming an outer limiting membrane. After five weeks a more mature-like structure was revealed. Photoreceptor cells had developed both inner and outer segments and synaptic terminals. The transplants were heterogeneously developed with some parts showing almost normal differentiation and others little. Incompletely differentiated synapse...

Distribution and function of the adrenergic and cholinergic receptors in the fetal calf bladder during mid‐gestational age

Previous studies on the developing fetal bovine bladder demonstrate that compliance is low during early stages of fetal development and increases with fetal age. In addition, the pharmacological response of isolated fetal bovine bladder smooth muscle strips to field stimulation and bethanechol increased in proportion with the gestational age. In the adult bladder (rabbit), the contractile response to autonomic receptor stimulation and the autonomic receptor density showed a parallel gradation in the the bladder between bladder dome and the urethra. The present studies were designed to determine the distribution of the cholinergic and adrenergic receptors in the urinary bladder of the fetal calf at mid-gestational age, and to correlate the receptor density with the magnitude of the response to receptor stimulation. Each bladder body was separated into upper, middle, and lower segments. For the functional studies, circular and longitudinal strips were cut from each bladder segment and stimulated with field stimulation (FS), bethanechol, methoxamine, isoproterenol, and KCl. Autonomic receptor assays were performed using 3H-QNB (muscarinic cholinergic), 3H-DHE (alpha adrenergic), and 3H-DHA (beta adrenergic) as ligands. In general, there were no significant differences in receptor density among the three bladder segments. However, the density of muscarinic receptors was significantly greater than the density of alpha- or beta-adrenergic receptors for all bladder segments. The receptor densities correlated very well with the functional response of isolated bladder strips to the specific autonomic agonists. The contractile response of isolated bladder strips to the specific autonomic agonists. The contractile responses of the strips to FS, bethanechol, and methoxamine were not significantly different among the three different bladder segments.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of prolactin on the secretion of dehydroepiandrosterone (DHEA), its sulfate (DHEA-S), and cortisol by the human fetal adrenal in vitro.

The effect of prolactin on the secretions of dehydroepiandrosterone (DHEA) and its sulfate (DHEA-S) as well as that of cortisol were studied in vitro in order to investigate the possible regulatory role of prolactin on steroidogenesis of the human fetal adrenal at mid-gestational age. The addition of 0.5 microgram/ml of human prolactin to the incubation medium produced a significant (P less than 0.05) increase in DHEA, DHEA-S, and cortisol secretion. These results indicate that prolactin has a regulatory role in steroidogenesis in the human fetal adrenal at mid-gestation.