Previous studies have poorly described the initial development process of the tendinous intersections of the rectus abdominis muscle (RAM). The present study aimed to observe the formation of tendinous intersections in the RAM during the early fetal period using diffusion tensor imaging (DTI). Fifteen human fetal specimens (crown-rump length [CRL]: 39.5-93.7 mm) were selected. Three-dimensional measurements revealed that Zone-4 (i.e., the zone between the pubic symphysis and the caudal base of the umbilical ring in the RAM) had a smaller width and was thicker than Zone-1 and Zone-2 (i.e., the zones between the costal arch and the cranial base of the umbilical ring) and Zone-3 (i.e., the zone at the umbilical ring). Characteristics of tendinous intersections in the RAM during the early fetal period were assessed according to number, size, type, laterality, and sex. The mean number of tendinous intersections on both sides was 3.1 (range: 2.0-4.0), and 21% of specimens had only two tendinous intersections, which was higher than that reported in previous adult studies. The present data suggest that the formation of tendinous intersections was still in progress in specimens with two tendinous intersections in the RAM and that the third tendinous intersection was formed in Zone-2. Ordinal logistic regression via generalized estimating equations revealed that the odds for a higher type of tendinous intersections in Zone-1 and Zone-2 were significantly higher than those in Zone-4 (adjusted odds ratio: 14.85, 8.84). The odds for the presence of incomplete types (tendinous intersections that could not completely transverse the RAM) in Zone-3 were significantly higher than those in Zone-1 (adjusted odds ratio: 7.4). The odds for missing tendinous intersections in Zone-4 were significantly higher than those in Zone-1 (adjusted odds ratio: 20.5). These zonal differences in the formation of tendinous intersections were consistent with those observed in previous adult studies. In this study, DTI detected tendinous intersections in a sample with a CRL of 45.8 mm (approximately 11 weeks of gestation), which is earlier than that in previous histological findings, indicating that the RAM does not have mature tendinous intersections until the 17th week of gestation. In conclusion, DTI could detect the premature differentiation of tendinous intersection formation. Our data may aid in elucidating the developmental processes of tendinous intersections in the RAM.

In human fetuses, the left hepatic artery (LHA) issues the marginal artery that runs along the umbilical vein and, sometimes, reaches the umbilicus. The further observation demonstrated that, in 5 of 12 Japanese midterm fetuses (crown-rump length mm: 46, 50, 54, 59, 102), the marginal artery issued not only a thin umbilical branch but also a liver parenchymal branch that took a posterosuperior recurrent course in a peritoneal fold and supplied the anterior surface of the liver left lobe (segment III). However, in 22 Spanish fetuses of which gestational ages corresponded to the Japanese ones, we did not find the parenchymal branch. Therefore, between human populations, there seemed to be a considerable difference in the incidence as to whether or not the marginal artery issues the liver parenchymal branch. The parenchymal branch might be degenerated at the later stages due to friction between the liver free surface and growing diaphragm.

UNASSIGNED: The temporomandibular joint (TMJ) is a synovial joint that allows the complex movements essential for life. It connects the jawbone to the skull, working as a sliding hinge. Moreover, pluripotent stem cells are a source of precursors and tissue-specific cells in developing organisms, however, their biodistribution in developing fetal tissues is weakly studied. The aim of our study was analyse immunohistochemical expression of Nanog, Oct-4, Sox-2 and Stat-3 and Sox-5, in TMJ tissue samples from human fetuses aged between the 12th and 20th weeks of intrauterine life.
UNASSIGNED: We fixed and processed TMJ tissue samples from human fetuses, histological sections and immunohistochemical procedures were carried out.
UNASSIGNED: TMJ histological studies examination did not reveal any difference in the tissue organization between the samples in the studied periods. Immunohistochemical analysis demonstrated that Oct-4 and Sox-2 lack their expression in TMJ. In contrast, Nanog was expressed in nucleous of proliferative layer of mandibular condyle, Stat-3 was expressed in nuclear cells of articular disc, Stat-3 and Sox-5 showed positive nuclear and cytoplasmic immunostaining in codrocyte layers and in ossification areas.
UNASSIGNED: Nanog acts in maintanence of pluripotency, Stat-3 in articular disc acts as a transcriptional factor. Stat-3 and Sox-2 act in chondrocyte and osteoblast diferentiation. Distribution of the cells, which express Nanog, Stat-3, and Sox-5 in TMJ tissue during fetal development, can help further understand its physiology, pathology, and repairing capacities.

The left atrium wall has several origins, including the body, appendage, septum, atrial-ventricular canal, posterior wall, and venous component. Here, we describe the morphogenesis of left atrium based on high-resolution imaging (phase-contrast X-ray computed tomography and magnetic resonance imaging). Twenty-three human embryos and 19 fetuses were selected for this study. Three-dimensional cardiac images were reconstructed, and the pulmonary veins and left atrium, including the left atrial appendage, were evaluated morphologically and quantitatively. The positions of the pericardial reflections were used as landmarks for the border of the pericardial cavity. The common pulmonary vein was observed in three specimens at Carnegie stages 17-18. The pericardium was detected at the four pulmonary veins (left superior, left inferior, right superior, and right inferior pulmonary veins) at one specimen at Carnegie stage 18 and all larger specimens, except the four samples. Our results suggest that the position of the pericardial reflections was determined at two pulmonary veins (right and left pulmonary vein) and four pulmonary veins almost simultaneously when the dorsal mesocardial connection between the embryo and heart regressed. The magnetic resonance images and reconstructed heart cavity images confirmed that the left atrium folds were present at the junction between the body and venous component. Three-dimensional reconstruction showed that the four pulmonary veins entered the dorsal left atrium tangentially from the lateral to the medial direction. More specifically, the right pulmonary veins entered at a greater angle than the left pulmonary veins. The distance between the superior and inferior pulmonary veins was shorter than that between the left and right pulmonary veins. Three-dimensional reconstruction showed that the venous component increased proportionally with growth. No noticeable differences in discrimination between the right and left parts of the venous component emerged, while the junction between the venous component and body gradually became inconspicuous but was still recognizable by the end of the observed early fetal period. The left superior pulmonary vein had the smallest cross-sectional area and most flattened shape, whereas the other three were similar in area and shape. The left atrial appendage had a large volume in the center and extended to the periphery as a lobe-like structure. The left atrial appendage orifice increased in the area and tended to become flatter with growth. The whole left atrium volume^(1/3) increased almost proportionally with growth, parallel to the whole heart volume. This study provided a three-dimensional and quantitative description of the developmental process of the left atrium, comprising the venous component and left atrial appendage formation, from the late embryonic to the early fetal stages.

UNASSIGNED: This study was aimed at determining the histomorphometry of the cerebellar cortical laminae and the dentate nucleus of the human fetal cerebellum; the number and shape of the neurons; and the gestational age of appearance of the cerebellar folia, white matter and arbor vitae cerebelli.
UNASSIGNED: Microscopic sections of the human fetal cerebellum stained with hematoxylin and eosin and Bielschowsky silver stain were studied.
UNASSIGNED: The thickness of the cortical laminae of the human fetal cerebellum varied among gestational weeks as follows: external granular layer: 36.06 ± 9.36-50.05 ± 34.06 μm, molecular layer: 32.76 ± 17.16-52 ± 28.6 μm, Purkinje cell layer: 9.36 ± 6.8-15.6 ± 4.68 μm and internal granular layer: 66.65 ± 24.42-146.63 ± 47.79 μm. Similarly, the number of neurons per field of view at 1000X under a compound microscope varied among gestational weeks as follows: external granular layer: 89.92 ± 42-142.84 ± 50, molecular layer: 15 ± 12.5-25 ± 8.25, Purkinje cell layer: 3.5 ± 1-5 ± 2.5 and internal granular layer: 98.5 ± 69.75-224 ± 47.White matter in the fetal cerebellum was already present at the age of 12th gestational week, whereas cerebellar folia appeared at 16-20 gestational weeks. Arbor vitae cerebelli and the dentate nucleus became conspicuous after the 20th gestational week. Fetal neurons were round except for Purkinje cells.
UNASSIGNED: The thickness and neuronal counts of the human fetal cerebellar cortical layers and the measurements of the dentate nucleus along with other histomorphological features varied with gestational age from the 12th week of gestation until birth.
UNASSIGNED: هدفت هذه الدراسة إلى إيجاد القياس النسيجي للصفيحة القشرية المخيخية والنواة المسننة لمخيخ الجنين البشري وأيضا دراسة عدد الخلايا العصبية وشكلها، وعمر الحمل لظهور الورقات المخيخية، والمادة البيضاء، وشجرة الحياة المخيخية.
UNASSIGNED: تمت دراسة المقاطع المجهرية من مخيخ الجنين البشري المصبوغة بالهيماتوكسيلين والأيوزين وبصبغة بيلشوفسكي.
UNASSIGNED: تباينت سماكة الصفيحة القشرية لمخيخ الجنين البشري بين الطبقة الحبيبية الخارجية- 36.06 ± 9.36 إلى 50.05 ± 34.06 ميكرومتر ، الطبقة الجزيئية- 32.76 ± 17.16 إلى 52 ± 28.6 ميكرومتر، طبقة خلايا بوركيني 9.36 ± 6.8 إلى 15.6 ± 4.68 ميكرومتر وطبقة حبيبية داخلية- 66.65 ± 24.42 إلى 146.63 ± 47.79 ميكرومتر في أسابيع الحمل المختلفة. وبالمثل، فإن عدد الخلايا العصبية لكل مجال رؤية عند قوة 1000 من المجهر المركب يختلف بين الطبقة الحبيبية الخارجية- 89.92 ± 42 إلى 142.84 ± 50 ، الطبقة الجزيئية- 15 ± 12.5 إلى 25 ± 8.25 ، طبقة خلايا بوركيني 3.5 ± 1 إلى 5 ± 2.5 وطبقة حبيبية داخلية- 98.5 ± 69.75 إلى 224 ± 47 في أسابيع الحمل المختلفة. كانت المادة البيضاء في مخيخ الجنين موجودة بالفعل في عمر الأسبوع الثاني عشر من الحمل بينما ظهرت الورقات المخيخية في الأسبوع 16–20 من الحمل. أصبحت شجرة الحياة المخيخية والنواة المسننة واضحة بعد الأسبوع العشرين من الحمل. كانت الخلايا العصبية الجنينية مستديرة باستثناء خلية بوركيني.
UNASSIGNED: تختلف سماكة وتعداد الخلايا العصبية للطبقات القشرية المخيخية للجنين البشري وقياسات النواة المسننة جنبًا إلى جنب مع السمات النسيجية الأخرى مع تقدم عمر الحمل من الأسبوع الثاني عشر من الحمل حتى الولادة.

The human fetal sacroiliac joint (SIJ) is characterized by unequal development of the paired bones and delayed cavitation. Thus, during the long in utero period, the bony ilium becomes adjacent to the cartilaginous sacrum. This mor-phology may be analogous to that of the temporomandibular joint (TMJ). We examined horizontal histological sections of 24 fetuses at 10-30 weeks and compared the timing and sequences of joint cartilage development, cavitation, and ossification of the ilium. We also examined histological sections of the TMJ and humeroradial joint, because these also contain a disk or disk-like structure. In the ilium, endochondral ossification started in the anterior side of the SIJ, extended posteriorly and reached the joint at 12 weeks GA, and then extended over the joint at 15 weeks GA. Likewise, the joint cartilage appeared at the anterior end of the future SIJ at 12 weeks GA, and extended along the bony ilium posteriorly to cover the entire SIJ at 26 weeks GA. The cavitation started at 15 weeks GA. Therefore, joint cartilage development seemed to follow the ossification of the ilium by extending along the SIJ, and cavitation then occurred. This sequence \"ossification, followed by joint cartilage formation, and then cavitation\" did not occur in the TMJ or humeroradial joint. The TMJ had a periosteum-like membrane that covered the joint surface, but the humeroradial joint did not. After muscle contraction starts, it is likely that the mechanical stress from the bony ilium induces development of joint cartilage.

Human genome editing has been increasingly explored to determine if it can be used to eradicate genetic diseases like sickle cell disease, but it has also been surrounded by a wide variety of ethical dilemmas. The purpose of this review was to conduct a scoping review of the ethics of therapeutic human genome editing in terms of philosophy, theology, public perspectives, and research ethics. A systemized search of PubMed, Embase, Ovid MEDLINE, and Web of Science was conducted. The initial search resulted in 4,445 articles, and after removing 1,750 duplicates and screening the remaining 2,695 articles, 27 final articles were selected for the final analysis. From a philosophical and theological standpoint, therapeutic human genome editing was generally ethically acceptable. Worldwide public perspectives were also in agreement except for the Oceanic region, which disagreed mainly due to the possible effects on future generations. Lastly, human research ethics revealed that women were not always included in informed consent, and that child autonomy needs to be preserved. Further research is needed to determine adverse effects on the mother, fetus, and future generations.

OBJECTIVE: To compare fetal and adult morphologies of the orbital muscle (OM) and to describe the detailed topographical anatomy in adults.
METHODS: Using unilateral orbits from 15 near-term fetuses and 21 elderly cadavers, semiserial horizontal or sagittal paraffin sections were prepared at intervals of 20-100 µm. In addition to routine histology, we performed immunohistochemistry for smooth muscle actin.
RESULTS: At near term, the OM consistently extended widely from the zygomatic bone or the greater wing of the sphenoid to the maxilla or ethmoid. Thus, it was a large sheet covering the future inferior orbital fissure. In contrast, the adult OM was a thin and small muscle bundle connecting (1) the greater wing of the sphenoid to the maxilla (11/19 cadavers), (2) the lesser wing of the sphenoid to the maxilla (5/19) or the greater wing (3/19). The small OM was likely to be restricted within the greater wing (5/19 cadavers) or the maxilla (3/19). Two of these five types of OM coexisted in eight orbits. OM attachment to the lesser wing was not seen in fetuses, whereas ethmoid attachment was absent in adults.
CONCLUSIONS: The lesser wing attachment of the OM seemed to establish after birth. A growing common origin of the three recti was likely involved in \"stealing\" the near-term OM attachment from the ethmoid. The strong immunoreactivity of remnant-like OM in the elderly suggests that OM contraction is still likely to occur against the increased flow through a thin vein. However, the contraction might have no clinical significance.

Since the fissula ante fenestram (FAF) is considered as a focus of otosclerotic lesion and a route of perilymph leakage, there are few description of prenatal development of the cartilaginous canal passing though the cochlear wall. We examined the sagittal and frontal histological sections of the ear from 32 human fetuses at 8-37 weeks of gestational age. At 8-12 weeks, in the immediately anterior side of a connection between the cochlear and canalicular parts of the otic capsule cartilage, the FAF appeared as a tear of a cartilage between the basal and second turns of the cochlea. The tear became a slit opening to the scala vestibuli. At 13-15 weeks, the FAF, less than 1.2 mm in length, had the anterosuperior and postero-inferior apertures: the former was near the geniculate ganglion and became closed after 15 weeks, while the latter approached the oval window. Third trimester fetuses, the FAF, 1.5-2.0 mm in length, consistently carried a single, postero-inferior aperture extending along the anterior margin of the oval window and it contained no definite epithelium and vessel. Although it was endochondral ossification, there was no clear zonation in cartilage cells of the FAF. A mechanical stress during three-dimensional coiling of the cochlear ducts seemed to provide the FAF. After the FAF was established, the stapes footplate might use a part of the inferior aperture for the syndesmosis. A specific ossification was seen in the FAF, but it might rarely cause the pathological syndesmosis.

OBJECTIVE: The longissimus (LO) and iliocostalis (IC) of adults consist of myofibers extending from the superolateral to the inferomedial side of the back and, because of the same course, they are fused in the thoracolumbar region. The LO also has a medial attachment to the long myofibers of the transversospinalis (TS) showing a course from the superomedial to the inferolateral side. However, there is apparently no information regarding when and how these similar longitudinal muscles differentiate from a cluster of dorsomedial myotome cells.
METHODS: We examined sagittal and horizontal sections of the trunks of 39 human embryos and fetuses (18-330 mm crown-rump length).
RESULTS: At 6-7 weeks gestational age (GA), the surface aponeurosis appeared prior to and independent of the thoracolumbar fascia. At 6-9 weeks GA, the LO myofibers had a postero-inferior course, from the transverse process to the initial aponeurosis, whereas the TS myofibers had a postero-superior course, from a lateral extension of the intertransverse ligament to the aponeurosis. However, the IC consisted of supracostal longitudinal myofibers and was distant from the LO until 12 weeks GA. Because of the lack of ligamentous attachments and ribs, myofibers of the TS, LO, and IC took a similar inferior course in the lumbar region. When the early TS was represented by the transverso-aponeurotic muscle, consequently, the LO corresponded to the aponeuro-transversal muscle and was independent from the IC.
CONCLUSIONS: The classical model of TS and LO development does not recognize the essential role of the aponeurosis identified here.