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Previous work suggested that cleft lip with or without cleft palate (CL/P)is genetically distinct from isolated cleft secondary palate (CP). Mutations in the Bmp target gene Msx1 in families with both forms of orofacial clefting has implicated Bmp signaling in both pathways. To dissect the function of Bmp signaling in orofacial clefting, we conditionally inactivated the type 1 Bmp receptor Bmpr1a in the facial primordia, using the Nestin cre transgenic line. Nestin cre; Bmpr1amutants had completely penetrant, bilateral CL/P with arrested tooth formation. The cleft secondary palate of Nestin cre; Bmpr1amutant embryos was associated with diminished cell proliferation in maxillary process mesenchyme and defective anterior posterior patterning. By contrast,we observed elevated apoptosis in the fusing region of the Nestin cre; Bmpr1a mutant medial nasal process. Moreover, conditional inactivation of the Bmp4 gene using the Nestin cretransgenic line resulted in isolated cleft lip. Our data uncover a Bmp4-Bmpr1a genetic pathway that functions in lip fusion, and reveal that Bmp signaling has distinct roles in lip and palate fusion.

Purpose To investigate the ocular manifestations and clinical characteristics of COVID‐19 patients caused by SARS‐CoV‐2 in Wuhan, China. Methods A total of 535 COVID‐19 patients were recruited at Mobile Cabin Hospital and Tongji Hospital. Information on demographic characteristics, exposure history, ocular symptoms, eye drop medication, eye protections, chronic eye diseases, systemic concomitant symptoms, radiologic findings and SARS‐CoV‐2 detection in nasopharyngeal swabs by real‐time PCR was collected from questionnaires and electronic medical records. Results Of 535 patients, 27 patients (5.0%) presented with conjunctival congestion and 4 patients had conjunctival congestion as the initial symptom. The average duration of conjunctival congestion was 5.9 ± 4.5 days (mean [SD]). The other ocular symptoms, including increased conjunctival secretion, ocular pain, photophobia, dry eye and tearing, were also found in patients with conjunctival congestion. Notably, hand–eye contact was independently correlated with conjunctival congestion in COVID‐19 patients. We also found that some COVID‐19 patients had chronic eye diseases, including conjunctivitis (33, 6.2%), xerophthalmia (24, 4.5%) and keratitis (14, 2.6%). Similar to the published studies, the most common clinical symptoms were fever, cough and fatigue. A total of 343 patients (64.1%) had positive SARS‐CoV‐2 detection in nasopharyngeal swabs. Conclusions Conjunctival congestion is one of the COVID‐19‐related ocular symptoms, which could occur as the initial symptoms. Frequent hand–eye contact may be the risk factor for conjunctival congestion in COVID‐19 patients. Screening of patients with conjunctival congestion by ophthalmologists is advocated during the outbreak of COVID‐19. It is essential to provide eye‐care equipment and strengthen education on eye protection.

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Summary We have investigated the structural basis by which the counter-clockwise direction of the amniote gut is established. The chirality of midgut looping is determined by left-right asymmetries in the cellular architecture of the dorsal mesentery, the structure that connects the primitive gut tube to the body wall. The mesenchymal cells of the dorsal mesentery are more condensed on the left side than on the right and, additionally, the overlying epithelium on the left side exhibits a columnar morphology, in contrast to a cuboidal morphology on the right. These properties are instructed by a set of transcription factors: Pitx2 and Isl1 specifically expressed on the left side, and Tbx18 expressed on the right, regulated downstream of the secreted protein Nodal which is present exclusively on the left side. The resultant differences in cellular organization cause the mesentery to assume a trapezoidal shape, tilting the primitive gut tube leftward.

Mandibular development is regulated by an interplay between a specified branchial arch ectoderm and a plastic mesenchyme. Moreover, signaling from the pharyngeal endoderm has been shown to be important for mandibular morphogenesis. To gain insight into the mechanisms regulating mandibular pattern, it is important to investigate the function of the epithelial-derived signals. Bmp4 is expressed in both distal, mandibular arch ectoderm and pharyngeal endoderm. Here, we show that deletion of Bmp4 in the mandibular ectoderm and to a lesser extent in the pharyngeal endoderm, resulted in severe defects in mandibular development. Furthermore, our data uncovered different Bmp4 thresholds for expression of the Bmp-dependent Msx1 and Msx2 genes in mandibular mesenchyme. We also found that ectodermal Fgf8 expression was both activated and repressed by Bmp4 in a dosage-dependent fashion indicating a novel Bmp4 function in threshold-specific regulation of Fgf8 transcription. Lastly, we provide evidence that Prx homeobox genes repress expression of an Msx2 transgene, previously shown to be Bmp4-responsive, revealing a mechanism for differential regulation of Msx1 and Msx2 by Bmp signaling.

To study the roles of key transcription factor networks, growth factors, and signaling molecules in the endoderm, notochord, and floorplate, we developed an inducible Cre-expressing system for altering gene function in this tissue. We generated an allele of Foxa2 that directs a tamoxifen-regulated Cre in the Foxa2 expression domain (Foxa2 mcm ). Activity of Foxa2 mcm recapitulates endogenous Foxa2 expression in endoderm, notochord, and floorplate. Efficiency of the system in a given tissue type was dose-and timingdependent. By comparing efficiency and location of Cre activity after administration of tamoxifen by oral gavage vs. intraperitoneal injection, we found that oral gavage achieves more rapid, robust recombination with less embryonic toxicity. This system will be useful for controlling the activity of floxed alleles at multiple stages of mouse embryogenesis and fetal development. Developmental Dynamics 237:447-453, 2008.

Objective: The novel coronavirus disease was first reported in Wuhan, China in December 2019 and is now pandemic all over the world.Previous study has reported several COVID-19 cases with conjunctivitis.However, the complete profiling of COVID-19 related ocular symptoms and diseases are still missing. We aim to investigate the ocular manifestations and clinical characteristics of COVID-19 patients. Methods:A total of five hundred and thirty-four patients were recruited at Mobile Cabin Hospital and Tongji Hospital. We collected information on demographic characteristics, exposure history, ocular symptoms, systemic concomitant symptoms, eye drop medication, eye protections, radiologic findings, and SARS-CoV-2 detection in nasopharyngeal swabs by RT-PCR from questionnaires and electronic medical records.