Expression of the Tgfß2 gene during chick embryogenesis.

We performed a comprehensive analysis of the expression of transforming growth factor (TGF) ß2 during chick embryogenesis from stage 6 to 30 (Hamburger and Hamilton, J Morphol 1951;88:49-92) using in situ hybridization. During cardiogenesis, Tgfß2 was expressed in the endothelial/mesenchymal cells of the valvulo-septal endocardial cushion tissue and in the epicardium until the end of embryogenesis. During the formation of major arteries, Tgfß2 was localized in smooth muscle progenitors but not in the vascular endothelium. During limb development, Tgfß2 was expressed in the mesenchymal cells in the presumptive limb regions at stage 16, and thereafter it was localized in the skeletal muscle progenitors. In addition, strong Tgfß2 expression was seen in the mesenchymal cells in the pharyngeal arches. Tgfß2 mRNA was also detected in other mesoderm-derived tissues, such as the developing bone and pleura. During ectoderm development, Tgfß2 was expressed in the floor plate of the neural tube, lens, optic nerve, and otic vesicle. In addition, Tgfß2 was expressed in the developing gut epithelium. Our results suggest that TGFß2 plays an important role not only in epithelial-mesenchymal interactions but also in cell differentiation and migration and cell death during chick embryogenesis. We also found that chick and mouse Tgfß2 RNA show very similar patterns of expression during embryogenesis. Chick embryos can serve as a useful model to increase our understanding in the roles of TGFß2 in cell-cell interactions, cell differentiation, and proliferation during organogenesis.

Tenascin C may regulate the recruitment of smooth muscle cells during coronary artery development.

Tenascin C (TNC) is an extracellular glycoprotein that is thought to be involved in tissue remodeling during organogenesis and regeneration. Using avian embryonic hearts, we investigated the spatiotemporal expression patterns of TNC during the formation of the proximal coronary artery. Immunohistochemistry showed that TNC was deposited around the developing coronary stem and that TNC colocalized with vascular smooth muscle α-actin. A quail-chick chimera, in which a quail proepicardial organ (PEO) had been transplanted, showed that quail tissue-derived cells contributed to the establishment of the endothelial and mural cells of the proximal coronary artery, and the quail tissue-derived mural cells displayed TNC. Proepicardial cells cultured in TNC showed the myofibroblast/smooth muscle cell phenotype and neutralizing anti-TNC antibody suppressed the expression of smooth muscle markers. These observations suggest that TNC plays a role in the mural smooth muscle development of the nascent proximal coronary artery.

Roles of TGFbeta and BMP during valvulo-septal endocardial cushion formation.

The primordia of valves and the atrioventricular septum arise from endocardial cushion tissue that is formed in the outflow tract (OFT) and in the atrioventricular (AV) regions during cardiogenesis. Abnormal development of the endocardial cushion results in various congenital heart diseases. Endocardial epithelial-mesenchymal transformation (EMT) is a critical process in cushion tissue formation and is regulated by many factors, such as growth factors, intercellular signaling molecules, transcription factors, and extracellular matrices. A signal that is produced by the myocardium of the AV and OFT regions and transferred to the adjacent endocardium across the extracellular matrix mediates EMT. Studies in vitro and genetic analyses have shown that transforming growth factor beta and bone morphogenetic protein play central roles in the regulation of EMT during cushion tissue formation.

Effect of smoking and CYP2D6 polymorphisms on the extent of fluvoxamine-alprazolam interaction in patients with psychosomatic disease.

PURPOSE: Fluvoxamine (FVX) is metabolized by cytochrome P450 (CYP) 2D6 and CYP1A2 and inhibits CYP3A4. The aim of this study was to investigate the factors responsible for interindividual variability in the extent of interaction between FVX and alprazolam (ALP). METHODS: Blood samples were taken from 49 depressive patients to determine plasma concentration of FVX, ALP or both. Twenty-four samples were taken during the FVX-alone period, 21 samples during the ALP-alone period and 30 samples during the FVX-ALP period. Subjects were also genotyped for CYP2D6. RESULTS: The concentration-to-dose (C/D) ratio of ALP during the FVX-treatment period was significantly higher than that during the ALP-alone period. The CYP2D6 genotype affected neither the C/D ratios of FVX nor the extent of interaction. The mean C/D ratio of FVX in smokers was reduced by more than 30% in comparison with that in non-smokers. The mean C/D ratio of ALP in non-smokers was increased by FVX, while that in smokers was unchanged. CONCLUSIONS: The extent of interaction between FVX and ALP may be affected by smoking, which alters the C/D ratio of FVX. Therefore, when FVX and ALP are concomitantly administered, it should be noted that non-smokers may exhibit greater drug interaction than smokers.

Heart myofibrillogenesis occurs in isolated chick posterior blastoderm: a culture model.

Early cardiogenesis including myofibrillogenesis is a critical event during development. -Recently we showed that prospective cardiomyocytes reside in the posterior lateral blastoderm in the chick embryo. Here we cultured the posterior region of the chick blastoderm in serum-free medium and observed the process of myofibrillogenesis by immunohistochemistry. After 48 hours, explants expressed sarcomeric proteins (sarcomeric alpha-actinin, 61%; smooth muscle alpha-actin, 95%; Z-line titin, 56%; sarcomeric myosin, 48%); however, they did not yet show a mature striation. After 72 hours, more than 92% of explants expressed I-Z-I proteins, which were incorporated into the striation in 75% of explants or more (sarcomeric alpha-actinin, 75%; smooth muscle alpha-actin, 81%; Z-line titin, 83%). Sarcomeric myosin was -expressed in 63% of explants and incorporated into A-bands in 37%. The percentage incidence of expression or striation of I-Z-I proteins was significantly higher than that of sarcomeric myosin. Results suggested that the nascent I-Z-I components appeared to be generated independently of A-bands in the cultured posterior blastoderm, and that the process of myofibrillogenesis observed in our culture model faithfully reflected that in vivo. Our blastoderm culture model appeared to be useful to investigate the mechanisms regulating the early cardiogenesis.

Understanding heart development and congenital heart defects through developmental biology: a segmental approach.

ABSTRACT The heart is the first organ to form and function during development. In the pregastrula chick embryo, cells contributing to the heart are found in the postero-lateral epiblast. During the pregastrula stages, interaction between the posterior epiblast and hypoblast is required for the anterior lateral plate mesoderm (ALM) to form, from which the heart will later develop. This tissue interaction is replaced by an Activin-like signal in culture. During gastrulation, the ALM is committed to the heart lineage by endoderm-secreted BMP and subsequently differentiates into cardiomyocyte. The right and left precardiac mesoderms migrate toward the ventral midline to form the beating primitive heart tube. Then, the heart tube generates a right-side bend, and the d-loop and presumptive heart segments begin to appear segmentally: outflow tract (OT), right ventricle, left ventricle, atrioventricular (AV) canal, atrium and sinus venosus. T-box transcription factors are involved in the formation of the heart segments: Tbx5 identifies the left ventricle and Tbx20 the right ventricle. After the formation of the heart segments, endothelial cells in the OT and AV regions transform into mesenchyme and generate valvuloseptal endocardial cushion tissue. This phenomenon is called endocardial EMT (epithelial-mesenchymal transformation) and is regulated mainly by BMP and TGFbeta. Finally, heart septa that have developed in the OT, ventricle, AV canal and atrium come into alignment and fuse, resulting in the completion of the four-chambered heart. Altered development seen in the cardiogenetic process is involved in the pathogenesis of congenital heart defects. Therefore, understanding the molecular nature regulating the 'nodal point' during heart development is important in order to understand the etiology of congenital heart defects, as well as normal heart development.

What does pain or discomfort in irritable bowel syndrome mean?

Despite many studies on pain of functional gastrointestinal disorders (FGID), the pain mechanism of FGID is not well understood, and pain treatment of FGID is not established. Following our former functional dyspepsia (FD) study, we proposed two subgroups of patients with irritable bowel syndrome (IBS), pain and discomfort (not pain). The duration of disease of discomfort IBS patients was longer than that of pain IBS patients (P < 0.05) The rate of anxiety disorder of pain IBS patients tended to be higher than that of discomfort IBS patients (P = 0.07172). Fifteen (15.2%) of 99 pain IBS patients and 1 (3.4%) of 29 discomfort IBS patients overlapped FD (P < 0.1). We expected that a common psychosocial mechanism would influence both pain dyspepsia patients and pain IBS patients, however, there were some differences between these FGID patients with pain. Anxiety in IBS patients with lower gastrointestinal pain seems to be important in their treatment.

Expression of tbx20 RNA during chick heart development.

The T-box gene family encodes a set of transcription factors that are involved in various developmental processes. We isolated tbx20 gene from chick embryos and examined in detail its expression patterns during heart development. In situ hybridization showed that tbx20 was expressed in the lateral plate mesoderm and subsequently in the primitive heart tube. At stages of looped heart, tbx20 was localized in the outflow tract (OT) and atrioventricular (AV) canal, in which valvuloseptal endocardial cushion develops. At later stages, although tbx20 was expressed predominantly in the nascent right ventricle, transcripts of tbx20 were down-regulated in the left ventricle. These results suggest that tbx20 may play important roles in a variety of developmental processes in cardiogenesis, such as chamber-specification and septation.

Development of proximal coronary arteries in quail embryonic heart: multiple capillaries penetrating the aortic sinus fuse to form main coronary trunk.

Studies have shown that the proximal coronary artery (PCA) develops via endothelial ingrowth from the peritruncal ring (PR) of the coronary vasculature. However, the details of PCA formation remain unclear. We examined the development of PCAs in quail embryonic hearts from 5 to 9 days of incubation (embryonic day [ED]) using double-immunostaining for QH1 (quail endothelial marker) and smooth muscle alpha-actin. At 6 to 7 ED, several QH1-positive endothelial strands from the PR penetrated the facing sinuses, and in some embryos, several endothelial strands penetrated the posterior (noncoronary) sinus. At 7 to 8 ED, the endothelial strands penetrating the facing sinuses seemed to fuse, forming a proximal coronary stem that was demarcated from the aortic wall by the nascent smooth muscle layer of the coronary artery. By 9 ED, two coronary stems were completely formed, and the endothelial strands previously penetrating the noncoronary sinus had disappeared. Confocal microscopy at 6 ED revealed discontinuous QH1-positive endothelial progenitors in the aortic wall at sites where the endothelial strands would later develop. Observations demonstrate that during the formation of the PCA, endothelial strands from the PR penetrate the facing sinuses and then fuse, whereas those strands penetrating the noncoronary sinus disappear. Thereafter, the coronary artery tunica media demarcates the definitive PCA from the aortic media.

Relationship between attention and arousal level in schizophrenia.

The purpose of the present paper was to clarify the link between the attention and arousal level that supports the basis of the cognitive dysfunction in schizophrenia, by investigating the relationship between the simple reaction time and the closed-eye eye movements in 30 patients with schizophrenia and 20 healthy controls. In terms of closed-eye eye movements during the simple reaction time test, healthy controls showed an increase of s-type (small and slow) eye movements after the end of the preparatory interval (PI) in both regular and irregular series, while the patients with schizophrenia, particularly those in whom the cross-over phenomenon was observed, showed no changes and maintained a hyperarousal level during the regular PI test. These results indicate that the patients with schizophrenia could not maintain appropriate attention during the burden tasks and their hyperarousal level persisted. It is therefore suggested that there is a close relationship between attentional deficit and hyperarousal among patients with schizophrenia.

Exploratory eye movements during the Benton Visual Retention Test: characteristics of visual behavior in schizophrenia.

In order to investigate the relationship between the behavioral patterns and clinical symptomatology in schizophrenia, exploratory eye movements of schizophrenic subjects and healthy controls during the Benton Visual Retention Test were examined using an eye-mark recorder. The results were as follows: (i) with card 1, the number of eye fixations of schizophrenic subjects was fewer, and the total and mean eye scanning lengths of schizophrenic subjects were shorter than those of healthy controls; (ii) with card 3, almost none of the schizophrenic subjects looked at the blank area opposite the peripheral figure on the right; (iii) with cards 3, 5, 6 and 9 there were some schizophrenic subjects who did not look at the peripheral figures; (iv) with card 6, many of the schizophrenic subjects made stereotypical movements; (v) with card 9, schizophrenic subjects used a narrow vertical gaze to look at the large figure on the right. Based on these characteristics among the schizophrenic subjects themselves, factors such as longer eye scanning length, looking at peripheral figures without fail, and not making stereotypical movements were reflected directly in the results of the Benton test, while there was no relationship between the width of the vertical gaze and the Benton results. Correlations between visual behavior and some psychiatric symptoms were observed. The visual behavioral patterns of schizophrenic subjects were various according to the characteristics of the Benton figures, while those of normal subjects were always almost the same. It was suggested that these results were caused by disturbances of the mental attitude of schizophrenic subjects toward objects or environments.

Significance of bone morphogenetic protein-4 function in the initial myofibrillogenesis of chick cardiogenesis.

The heart is the first organ to form and function during vertebrate embryogenesis. Using a secreted protein, noggin, which specifically antagonizes bone morphogenetic protein (BMP)-2 and -4, we examined the role played by BMP during the initial myofibrillogenesis in chick cultured precardiac mesoendoderm (mesoderm + endoderm; ME). Conditioned medium from COS7 cells transfected with Xenopus noggin cDNA inhibited the expression of sarcomeric proteins (such as sarcomeric alpha-actinin, Z-line titin, and sarcomeric myosin), and so myofibrillogenesis was perturbed in cultured stage 4 precardiac ME; however, it did not inhibit the expression of smooth muscle alpha-actin (the first isoform of alpha-actin expressed during cardiogenesis). In cultured stage 5 precardiac ME, noggin did not inhibit either the formation of I-Z-I components or the expression of sarcomeric myosin, but it did inhibit the formation of A-bands. Although BMP4 was required to induce expressions of sarcomeric alpha-actinin, titin, and sarcomeric myosin in cultured stage 6 posterolateral mesoderm (noncardiogenic mesoderm), smooth muscle alpha-actin was expressed without the addition of BMP4. Interestingly, in cultured stage 6 posterolateral mesoderm, BMP2 induced the expressions of sarcomeric alpha-actinin and titin, but not of sarcomeric myosin. These results suggest that (1) BMP4 function lies upstream of the initial formation of I-Z-I components and A-bands separately in a stage-dependent manner, and (2) at least two signaling pathways are involved in the initial cardiac myofibrillogenesis: one is an unknown pathway responsible for the expression of smooth muscle alpha-actin; the other is BMP signaling, which is involved in the expression of sarcomeric alpha-actinin, titin, and sarcomeric myosin.