An immunohistochemical study of matrix components in primary and secondary cartilages of embryonic chick skull.

OBJECTIVES: This study aimed to compare the extracellular matrix of primary cartilage with the secondary cartilage of chicks using immunohistochemical analyses in order to understand the features of chick secondary chondrogenesis. METHODS: Immunohistochemical analysis was performed on the extracellular matrix of quadrate (primary), squamosal, surangular, and anterior pterygoid secondary cartilages using various antibodies targeting the extracellular matrix of cartilage and bone. RESULTS: The localization of collagen types I, II, and X, versican, aggrecan, hyaluronan, link protein, and tenascin-C was identified in the quadrate cartilage, with variations within and between the regions. Newly formed squamosal and surangular secondary cartilages showed simultaneous immunoreactivity for all molecules investigated. However, collagen type X immunoreactivity was not observed, and there was weak immunoreactivity for versican and aggrecan in the anterior pterygoid secondary cartilage. CONCLUSIONS: The immunohistochemical localization of extracellular matrix in the quadrate (primary) cartilage was comparable to that of long bone (primary) cartilage in mammals. The fibrocartilaginous nature and rapid differentiation into hypertrophic chondrocytes, which are known structural features of secondary cartilage, were confirmed in the extracellular matrix of squamosal and surangular secondary cartilages. Furthermore, these tissues appear to undergo developmental processes similar to those in mammals. However, the anterior pterygoid secondary cartilage exhibited unique features that differed from primary and other secondary cartilages, suggesting it is formed through a distinct developmental process.

An in situ hybridization study of syndecan family during the late stages of developing mouse molar tooth germ.

Expression of syndecan-1, 2, 3, and 4 mRNAs during the late stages of tooth germ formation was investigated by in situ hybridization, using [35S]-UTP-labeled cRNA probes. Syndecan-1 mRNA was mainly expressed in the stellate reticulum and stratum intermedium as well as at the cervical region of dental papilla/dental follicle during E18.5-P3.0. Expression in the dental epithelium was enhanced during the postnatal periods, which was supported by real-time RT-PCR analysis. These spatiotemporal expression patterns may suggest specific roles of syndecan-1 in tooth formation such as tooth eruption or root formation. Syndecan-3 mRNA expression became evident in odontoblasts at E18.5, but compared to collagen type I mRNA, which was strongly expressed at this stage, syndecan-3 expression in odontoblast was restricted in mature odontoblasts beneath the cusps during the postnatal periods. This result was also supported by real-time RT-PCR analysis, and indicated that syndecan-3 may be involved in the progress of dentinogenesis rather than in the initiation of it. Syndecan-4 mRNA roughly showed comparable expression patterns to those of syndecan-3. Syndecan-2 mRNA did not show significant expression during the experimental period, but real-time RT-PCR analysis suggested that syndecan-2 expression might be enhanced with hard tissue formation.

Association between underlying disease and serious events on a world cruise ship: A prospective cohort study.

BACKGROUND: This study aimed to clarify the effects of underlying diseases on clinical outcomes of patients aboard a world cruise ship. METHODS: This prospective cohort study included patients who sought physician consultations at an onboard clinic on a 105-day world cruise (September-December 201X) on a ship chartered by a Japanese travel agency. Multivariable logistic regression analysis was performed to ascertain whether any concurrent disease, such as hypertension, was associated with additional onboard treatment by the primary physician or serious events, including unexpected final disembarkation, temporary disembarkation for hospitalization ashore, shore-side referral, and onboard clinic admission. RESULTS: Of 313 patients, 182 (58%) had at least one underlying disease. Sixty-eight (22%) required additional treatment, and 24 (8%) experienced serious events. After adjusting for age, sex, and underlying diseases, the 60-69- and 70-74-year age groups had a lower risk of serious events than the ≤59-year age group (odds ratio [OR], 95% confidence interval [CI]: 0.24, 0.069-0.81; p = 0.022 and 0.045, 0.0051-0.47; p = 0.0055). Underlying disease was associated with serious events (OR, 95% CI: 3.2, 1.1-9.5; p = 0.036). CONCLUSIONS: Unexpected events can occur in patients on world cruises regardless of age. Preexisting diseases may confer higher risk of serious events.

An in situ hybridization study of the Syndecan family in the developing condylar cartilage of fetal mouse mandible.

Mandibular condylar cartilage is a representative secondary cartilage, differing from primary cartilage in various ways. Syndecan is a cell-surface heparan sulfate proteoglycan and speculated to be involved in chondrogenesis and osteogenesis. This study aimed to investigate the expression patterns of the syndecan family in the developing mouse mandibular condylar cartilage. At embryonic day (E)13.0 and E14.0, syndecan-1 and -2 mRNAs were expressed in the mesenchymal cell condensation of the condylar anlage. When condylar cartilage was formed at E15.0, syndecan-1 mRNA was expressed in the embryonic zone, wherein the mesenchymal cell condensation is located. Syndecan-2 mRNA was mainly expressed in the perichondrium. At E16.0, syndecan-1 was expressed from fibrous to flattened cell zones and syndecans-2 was expressed in the lower hypertrophic cell zone. Syndecan-3 mRNA was expressed in the condylar anlage at E13.0 and E13.5 but was not expressed in the condylar cartilage at E15.0. It was later expressed in the lower hypertrophic cell zone at E16.0. Syndecan-4 mRNA was expressed in the condylar anlage at E14.0 and the condylar cartilage at E15.0 and E16.0. These findings indicated that syndecans-1 and -2 could be involved in the formation from mesenchymal cell condensation to condylar cartilage. The different expression patterns of the syndecan family in the condylar and limb bud cartilage suggest the functional heterogeneity of chondrocytes in the primary and secondary cartilage.

The third vascular route of the inner ear or the canal of Cotugno: Its topographical anatomy, fetal development, and contribution to ossification of the otic capsule cartilage.

Three vascular routes to the inner ear are known: (a) through the internal acoustic meatus with the vestibulocochlear nerve; (b) from the endolymphatic duct aperture; and (c) along the canal of Cotugno (CC) inserted into the vestibular part of the ear from the superior or brain side. The third is believed to contain only veins. Examinations of 33 human embryos and fetuses at 6-40 weeks demonstrated that (a) the CC appeared as a recess of epidural mesenchymal tissues at the superior aspect of the otic capsule cartilage in embryos and it was inserted deeply to issue multiple peripheral divisions inferolaterally and posteriorly at midterm; (b) the CC consistently passed through a ring of the superior or anterior semicircular canal and contained both, the arteries from the vestibulocochlear nerve origin at the midbrain and the vein draining into the sigmoid sinus or petrosal sinuses; and (c) the CC appeared not to contribute to ossification of the otic capsule cartilage but, after endochondral ossification of the internal ear, woven bone development occurred along a smooth interface of the CC with the ossified ear. In contrast, another interface between the developing bone and the residual cartilage of the otic capsule was rough and wavy with many short bony columns, called osseous globules. In addition, the endolymphatic duct accompanied veins but no arteries. Our results show that the CC is a major vascular route to the vestibular part of the otic capsule cartilage, but its role appears to be limited after ossification.

An in situ hybridization study of decorin and biglycan mRNA in mouse osteoblasts in vivo.

In situ hybridization of decorin and biglycan mRNA, principal members of small leucine-rich proteoglycan, was performed using [35S]-labeled RNA probes, in the context of the hypothesis that they show different expression patterns associated with osteoblast differentiation in mice. We adopted two ossifying sites that can clearly follow the developmental process of bone formation: ossifying tympanic ring and developing bone collar of mandibular condylar cartilage. Decorin mRNA was expressed in osteoblasts of developing tympanic ring at E14.0, as well as of developing bone collar at E15.0, but biglycan mRNA was not, indicating decorin mRNA was expressed earlier in newly differentiating osteoblasts than biglycan. With maturation of osteoblasts, biglycan mRNA became expressed and maintained its expression both in the outer region (periosteum) and in the interior region (endosteum) of bone. By contrast, decorin mRNA expression was maintained in the outer region but diminished in the interior region. These results indicate that decorin and biglycan show differential expression patterns in differentiating osteoblasts and play specific roles in bone formation.

Abnormal Intestinal Anatomy in Late-stage Human Fetuses: Three Case Series.

OBJECTIVE: We reported three cases of fetuses with abnormal intestinal anatomy found during our recent study of the transverse mesocolon using 20 late-stage fetuses. CASES: The first case (CRL: 328 mm) appeared to have a duodenum and transverse colon trapped in Winslow's foramen (foramen epiploicum) and the duodenum superior portion elongated rightward. The second case (CRL: 264 mm) had a transverse colon inserted deeply into a space between the right kidney and duodenum. The third case (CRL: 276 mm) had a descending colon that ran inferiorly through a deep space between the left kidney and duodenum. Each case had a greater omentum that was shifted leftward, but this is usual. These 3 abnormalities were not evident in the anterior view during dissection of the liver, stomach, jejunum, and ileum. With underdeveloped pancreatic ducts due to unknown reason other than the internal hernia, the first case seemed to be fatal after birth. However, the second and third cases could have recovered after birth because there was no evidence of definite malrotation and because of loose attachments of the intestines to surrounding structures. CONCLUSIONS: The intestinal morphologies described here could cause some sort of symptoms, such as abdominal pain, whose cause might be difficult to determine.

Expression, localization and synthesis of small leucine-rich proteoglycans in developing mouse molar tooth germ.

The gene expression and protein synthesis of small leucine-rich proteoglycans (SLRPs), including decorin, biglycan, fibromodulin, and lumican, was analyzed in the context of the hypothesis that they are closely related to tooth formation. In situ hybridization, immunohistochemistry, and organ culture with metabolic labeling of [35S] were carried out in mouse first molar tooth germs of different developmental stages using ICR mice at embryonic day (E) 13.5 to postnatal day (P) 7.0. At the bud and cap stage, decorin mRNA was expressed only in the surrounding mesenchyme, but not within the tooth germ. Biglycan mRNA was then expressed in the condensing mesenchyme and the dental papilla of the tooth germ. At the apposition stage (late bell stage), both decorin and biglycan mRNA were expressed in odontoblasts, resulting in a switch of the pattern of expression within the different stages of odontoblast differentiation. Decorin mRNA was expressed earlier in newly differentiating odontoblasts than biglycan. With odontoblast maturation and dentin formation, decorin mRNA expression was diminished and localized to the newly differentiating odontoblasts at the cervical region. Simultaneously, biglycan mRNA took over and extended its expression throughout the new and mature odontoblasts. Both mRNAs were expressed in the dental pulp underlying the respective odontoblasts. At P7.0, both mRNAs were weakly expressed but maintained their spatial expression patterns. Immunostaining showed that biglycan was localized in the dental papillae and pulp. In addition, all four SLRPs showed clear immunostaining in predentin, although the expressions of fibromodulin and lumican mRNAs were not identified in the tooth germs examined. The organ culture data obtained supported the histological findings that biglycan is more predominant than decorin at the apposition stage. These results were used to identify biglycan as the principal molecule among the SLRPs investigated. Our findings indicate that decorin and biglycan show spatial and temporal differential expressions and play their own tissue-specific roles in tooth development.

Vermiform Appendix During the Repackaging Process from Umbilical Herniation to Fixation onto the Right Posterior Abdomen: A Study of Human Fetal Horizontal Sections.

The anatomical position of the vermiform appendix varies among adults, and these variations are responsible for differences in the symptoms of appendicitis. However, to date no study has examined how and when these variations occur during fetal development. The present study examined horizontal sections of 27 midterm fetuses (crown rump length [CRL] 38-97 mm, gestational age approximately 8-15 weeks). There were 10 fetuses (CRL 56 mm or more) in which the cecum and appendix were in a posterosuperior site near the right kidney (postmigration phase), and 12 fetuses (CRL 39-72 mm) in which the ileocecal junction and appendix remained on the visceral surface of the liver in the anterior or anterolateral abdominal cavity (migration phase, after physiological umbilical herniation). Analysis of the 12 fetuses in the migration phase indicated that the appendix extended inferiorly in eight fetuses and superiorly in four fetuses. Likewise, a "preileal" appendix (a morphology in which the distal part of the appendix was in front of the terminal ileum) was present in eight of these fetuses. Extension of the appendix superiorly or inferiorly during the migration phase seems unrelated to the topographical relationship of the appendix with the terminal ileum at the postmigration phase in fetuses and in adults. Conversely, it seems likely that a retroileal appendix leads to a coiled appendix behind the ileocecal junction. "Guidance" by the liver surface seemed to be important for posterior migration, which ended with the ascent of the liver. Clin. Anat., 33:667-677, 2020. © 2019 Wiley Periodicals, Inc.

Loss of autophagy in chondrocytes causes severe growth retardation.

Chondrogenesis is accompanied by not only cellular renovation, but also metabolic stress. Therefore, macroautophagy/autophagy is postulated to be involved in this process. Previous reports have shown that suppression of autophagy during chondrogenesis causes mild growth retardation. However, the role of autophagy in chondrocyte differentiation still largely remains unclear. Here, we show the important role of autophagy on chondrogenesis. The transition of mesenchymal cells to chondrocytes was severely impaired by ablation of Atg7, a gene essential for autophagy. Mice lacking Atg7 after the transition exhibited phenotypes severer than mutant mice in which Atg7 was removed before the transition. Atg7-deficient chondrocytes accumulated large numbers of glycogen granules, hardly proliferate and died specifically in the proliferative zone without any ER-stress signal. Our results suggest that the suppression of autophagy in prechondrogenic cells drives compensatory mechanism(s) that mitigate defective chondrogenesis, and that autophagy participates in glycogenolysis to supply glucose in avascular growth plates.Abbreviations: DDIT3/CHOP: DNA damage inducible transcript 3; ER: endoplasmic reticulum; NFE2L2/NRF2: nuclear factor, erythroid derived 2, like 2; SQSTM1/p62: sequestosome 1; STBD1: starch-binding domain-containing protein 1.

Immunohistochemical and ultrastructural evaluation of matrix components in mandibular condylar cartilage in comparison with growth plate cartilage in cartilage calcification insufficient rats.

Matrix components of growth plate cartilage and mandibular condylar cartilage were immunohistochemically analyzed in cartilage calcification insufficient (CCI) rats, a model for dwarf rats. Reduction in total tibial length, elongation of growth plate, and appearance of noncartilaginous regions in the growth plate were observed in CCI rats. Immunoreactivity for type I collagen and hyaluronic acid (HA) staining were observed in the noncartilaginous region. However, weak immunoreactivity was observed for aggrecan, collagen types II and X, and decorin in this region. Transmission electron microscopy indicated that the noncartilaginous region showed a loose network of thin collagen fibrils, indicating that HA is predominantly involved in capturing space of the noncartilaginous region in the growth plate. Meanwhile, the mandibular condylar cartilage in CCI rats also showed elongation of the cartilaginous region and had a noncartilaginous region, predominantly comprising thick collagen fibrils. The structural difference between the two types of cartilages in CCI rats may be due to the presence of the fibrous cell zone and the fibrocartilaginous nature of the normal condylar cartilage. Additionally, the reduction in mandibular length was relatively less than the reduction in tibial length. The outline of the condylar process showed only slight abnormality. These results suggest that the condylar cartilage compensated its growth by supplying the characteristic noncartilaginous region effectively and may adapt to severe structural changes observed in CCI rats.

Nervus terminalis and nerves to the vomeronasal organ: a study using human fetal specimens.

The human nervus terminalis (terminal nerve) and the nerves to the vomeronasal organ (VNON) are both associated with the olfactory nerves and are of major interest to embryologists. However, there is still limited knowledge on their topographical anatomy in the nasal septum and on the number and distribution of ganglion cells along and near the cribriform plate of the ethmoid bone. We observed serial or semiserial sections of 30 fetuses at 7-18 weeks (crown rump length [CRL], 25-160 mm). Calretinin and S100 protein staining demonstrated not only the terminal nerve along the anterior edge of the perpendicular lamina of the ethmoid, but also the VNON along the posterior edge of the lamina. The terminal nerve was composed of 1-2 nerve bundles that passed through the anterior end of the cribriform plate, whereas the VNON consisted of 2-3 bundles behind the olfactory nerves. The terminal nerve ran along and crossed the posterior side of the nasal branch of the anterior ethmoidal nerve. Multiple clusters of small ganglion cells were found on the lateral surfaces of the ethmoid's crista galli, which are likely the origin of both the terminal nerve and VNON. The ganglions along the crista galli were ball-like and 15-20 µm in diameter and, ranged from 40-153 in unilateral number according to our counting at 21-µm-interval except for one specimen (480 neurons; CRL, 137 mm). An effect of nerve degeneration with increasing age seemed to be masked by a remarkable individual difference.

Histochemical and Ultrastructural Study of Developing Gonial Bone With Reference to Initial Ossification of the Malleus and Reduction of Meckel's Cartilage in Mice.

Development of mouse gonial bone and initial ossification process of malleus were investigated. Before the formation of the gonial bone, the osteogenic area expressing alkaline phosphatase and Runx2 mRNA was widely recognized inferior to Meckel's cartilage. The gonial bone was first formed within the perichondrium at E16.0 via intramembranous ossification, surrounded the lower part of Meckel's cartilage, and then continued to extend anteriorly and medially until postnatal day (P) 3.0. At P0, multinucleated chondroclasts started to resorb the mineralized cartilage matrix with ruffled borders at the initial ossification site of the malleus (most posterior part of Meckel's cartilage). Almost all CD31-positive capillaries did not run through the gonial bone but entered the cartilage through the site where the gonial bone was not attached, indicating the forms of the initial ossification site of the malleus are similar to those at the secondary ossification center rather than the primary ossification center in the long bone. Then, the reducing process of the posterior part of Meckel's cartilage with extending gonial bone was investigated. Numerous tartrate-resistant acid phosphatase-positive mononuclear cells invaded the reducing Meckel's cartilage, and the continuity between the malleus and Meckel's cartilage was completely lost by P3.5. Both the cartilage matrix and the perichondrium were degraded, and they seemed to be incorporated into the periosteum of the gonial bone. The tensor tympani and tensor veli palatini muscles were attached to the ligament extending from the gonial bone. These findings indicated that the gonial bone has multiple functions and plays important roles in cranial formation. Anat Rec, 302:1916-1933, 2019. © 2019 American Association for Anatomy.

Flap valve of the heart foramen ovale revisited: macroscopic and histologic observations of human near-term fetuses.

We assessed the flap valve of the foramen ovale (FO valve) by examining 30 hearts from human fetuses of gestational age 30-40 weeks. We dissected the hearts, examined their macroscopic morphology, and then prepared semiserial sagittal sections across the valve. Although the primary septum is expected to extend along the left atrial face, eight hearts had a superior rim of the fossa ovalis on the left atrial face that was too thick and high, so there was no smooth continuation with the valve. Moreover, three of these eight hearts each had a flap valve that was fused with a long and narrow plate arising from the caval orifice. Histological analysis indicated that 21 specimens each had a candidate primary septum that contained myocardium, although the left sinuatrial valve (LSAV) contained fibrous tissue, but little or no myocardium. In each of 17 hearts, a candidate primary septum was attached to the left atrial face of the fossa, and parts of the LSAV extended to and approached the right atrial face. However, seven of these 17 hearts each had a folded small primary septum. Another four of these 17 hearts each had an LSAV that extended widely to the fossa, and a candidate primary septum (which might be a remnant) attached to the left atrial side of the LSAV. These variations suggest that the LSAV makes a major contribution to the FO valve in some fetal hearts. Consequently, the fetal FO valve appears to have heterogeneous morphology and origin.

An in situ hybridization study of MMP-2, -9, -13, -14, TIMP-1, and -2 mRNA in fetal mouse mandibular condylar cartilage as compared with limb bud cartilage.

The main purpose of this in situ hybridization study was to investigate MMPs and TIMPs mRNA expression in developing mandibular condylar cartilage and limb bud cartilage. At E14.0, MMP-2, -14, TIMP-1 and -2 mRNAs were expressed in the periosteum of mandibular bone, and in the condylar anlage. At E15.0 MMP-2, -14, TIMP-1 and -2 mRNAs were expressed in the perichondrium of newly formed condylar cartilage and the periosteum of developing bone collar, whereas, expression of MMP-14 and TIMP-1 mRNAs were restricted to the inner layer of the periosteum/perichondrium. This expression patterns continued until E18.0. Further, from E13.0 to 14.0, in the developing tibial cartilage, MMP-2, -14, and TIMP-2 mRNAs were expressed in the periosteum/perichondrium, but weak MMP-14 and no TIMP-1 mRNA expression was recognized in the perichondrium. These results confirmed that the perichondrium of condylar cartilage has characteristics of periosteum, and suggested that MMPs and/or TIMPs are more actively involved in the development of condylar (secondary) cartilage than tibial (primary) cartilage. MMP-9-positive cells were observed in the bone collar of both types of cartilage, and they were consistent with osteoclasts/chondroclasts. MMP-13 mRNA expression was restricted to the chondrocytes of the lower hypertrophic cell zone in tibial cartilage at E14.0, indicating MMP-13 can be used as a marker for lower hypertrophic cell zone. It was also expressed in chondrocytes of newly formed condylar cartilage at E15.0, and continuously expressed in the lower hypertrophic cell zone until E18.0. These results confirmed that progenitor cells of condylar cartilage are rapidly differentiated into hypertrophic chondrocytes, which is a unique structural feature of secondary cartilage different from that of primary cartilage.

Effects of unilateral nasal obstruction on the characteristics of jaw-closing muscles in growing rats.

OBJECTIVES: Mouth breathing caused by nasal obstruction (owing to abnormal pressure of masticatory muscles) affects craniofacial growth and development. The influence of unilateral nasal obstruction on jaw-closing muscles was investigated in rats to reveal one of the etiologic mechanisms. MATERIALS AND METHODS: Forty 8-day-old male Wistar rats were used in this study. Experimental rats were subjected to left-sided nasal obstruction by burning the external nostril tissue at the age of 8 days. Pulse oxygen saturation was recorded each week. Morphologic changes were evaluated by staining with hematoxylin and eosin (to assess the cross-sectional area) and by adenosine triphosphatase activity staining (to assess the myosin heavy chain isoform composition). Immunohistochemical and reverse transcription quantitative real-time polymerase chain reaction analyses of tumor necrosis factor-α and glucose transporter 4 were carried out at 5 and 9 weeks of age. RESULTS: The cross-sectional area of the jaw-closing muscles was lower in the experimental group at 9 weeks of age. The percentage of myosin heavy chain-2a in masseter muscles was increased in the experimental group compared with the control group. An increase in the tumor necrosis factor-α messenger RNA and protein levels and a decrease in the glucose transporter 4 messenger RNA and protein levels at 5 and 9 weeks of age in the jaw-closing muscles in the experimental group were noted. CONCLUSIONS: Unilateral nasal obstruction could affect the morphology and contractile characteristics of jaw-closing muscles during growth in rats.

Topographical variations of the incisive canal and nasopalatine duct in human fetuses.

The incisive canal for nerves and vessels is generally thought to run along a suture between the incisive bone (IN) and maxilla. In contrast, there was a report saying the canal passes through the IN or primary palate in human fetuses. Examination of sagittal and frontal sections from 69 fetuses (31 of gestational age [GA] 9-15 weeks and 38 of GA 26-34 weeks) showed that the canal often penetrated the IN at the nasal half of its course and that, in other fetuses, the canal penetrated the IN along its entire course, irrespective of involvement of the nasopalatine duct. Canals developing in and corresponding to parts of the suture resulted in partial enlargement of the thin and tight sutures, which contained loose tissue, vessels, nerves and even a duct. Small processes of the IN were identified as upper irregular parts continuous with inferior main masses of bone in frontal sections but as bone fragments in sagittal sections. In some sections, a thin layer of the maxilla along the canal covered the medial or inferior aspect of the IN. Therefore, the incisive canal with or without duct exhibited a spectrum of variations in topographical relation to the IN-maxillary border. Because the primitive oronasal communication passes through the suture, the nasopalatine duct may have originated from the secondary developed elongation of the nasal epithelium at midterm. A large incisive fossa along the midline on the oral surface of the palate might make a macroscopic finding of variants difficult even in adults.

Topographical anatomy of the greater omentum and transverse mesocolon: a study using human fetuses.

The greater omentum covers the transverse colon from the anterior side in adults, but people might believe the morphology stable once established during fetal life. Sections from 49 midterm and 17 late-stage human fetuses, of gestational ages (GA) 8-15 and 30-38 weeks, respectively, showed complete fusion between the greater omentum and transverse mesocolon after physiological herniation at GA 8-9 weeks; the transverse colon attaching to the anterior aspect of the gastric antrum and pylorus at GA 10-15 weeks; the colon pushing the pylorus or superior portion of the duodenum upward (at GA 10-15 weeks and 30-38 weeks); and the greater omentum without covering the greater portion of the jejunum and ileum but shifted leftward (at GA 30-38 weeks). These subsequent topographical variations of the transverse colon with the stomach and duodenum included the colon tightly fusing with the stomach by a fibrous tissue and; the greater omentum and/or the mesocolon wedged between the stomach and transverse colon. Therefore, in combination, the colon was partly separated from the greater omentum. Moreover, at GA 30-38 weeks, the duodenum consistently showed a horizontal loop in contrast to the usual C-loop in the frontal plane. Consequently, after a complete fusion occurred once between the greater omentum and transverse mesocolon, the topographical change of the upper abdominal viscera seemed to modify, change or even break the initial fusion of the peritoneum. A logical lamination of the peritoneum seemed not to simply connect with the surgical application.

Craniofacial abnormality with skeletal dysplasia in mice lacking chondroitin sulfate N-acetylgalactosaminyltransferase-1.

Chondroitin sulfate (CS) proteoglycan is a major component of the extracellular matrix and plays an important part in organogenesis. To elucidate the roles of CS for craniofacial development, we analyzed the craniofacial morphology in CS N-acetylgalactosaminyltransferase-1 (T1) gene knockout (KO) mice. T1KO mice showed the impaired intramembranous ossification in the skull, and the final skull shape of adult mice included a shorter face, higher and broader calvaria. Some of T1KO mice exhibited severe facial developmental defect, such as eye defects and cleft lip and palate, causing embryonic lethality. At the postnatal stages, T1KO mice with severely reduced CS amounts showed malocclusion, general skeletal dysplasia and skin hyperextension, closely resembling Ehlers-Danlos syndrome-like connective tissue disorders. The production of collagen type 1 was significantly downregulated in T1KO mice, and the deposition of CS-binding molecules, Wnt3a, was decreased with CS in extracellular matrices. The collagen fibers were irregular and aggregated, and connective tissues were dysorganized in the skin and calvaria of T1KO mice. These results suggest that CS regulates the shape of the craniofacial skeleton by modulating connective tissue organization and that the remarkable reduction of CS induces hypoplasia of intramembranous ossification and cartilage anomaly, resulting in skeletal dysplasia.

Fetal Development of Fasciae around the Arm and Thigh Muscles: A Study Using Late Stage Fetuses.

To obtain a better understanding of multi-laminar deep fascia covering skeletal muscles, we examined nondecalcified histological sections of the arm and thigh of 20 human fetuses aged 25-33 weeks. Morphologies of the fasciae varied between sites and specimens, but the initial morphology was most likely to be a thin and loose sheet on the external surface of the muscles (fascia-1 or F1). When the F1 became wavy, thick and tight, it was detached from the muscle surface. Beneath the F1, the second lamina of fascia (F2) appeared on the muscle surface and it was also detached. In this manner at 25-33 weeks' gestation, fasciae covering the triceps and vastus lateralis muscles had a three-layered configuration (F1, F2, and F3). Due to significant individual variations, this process was not correlated to the ages and sizes of specimens. Muscle contractions might facilitate the detachment. In these muscles, the intramuscular tendon joined the F2 or F3 and the latter became thick and aponeurotic. Along the finally developed lamina, muscle fibers carried a desmin-positive spot for insertion. Increased laminae were accompanied by a reduced number of CD68-positive macrophages and, nerves were absent, near the developing fascia. In contrast to skin ligaments or superficial fasciae showing de novo development in loose tissue, a deep or muscle-covering fascia seemed to originate from the skeletal muscle itself at the surface, and this process was repeated to produce multi-layered fascia. Depending on sites, collagen fibers were added by the intramuscular tendon. Anat Rec, 301:1235-1243, 2018. © 2018 Wiley Periodicals, Inc.