Normal embryonic development of human heart is studied with special emphasis to the formation of atrioventricular and ventriculoarterial connections and their significance in congenital heart disease. Twenty nine human embryos and 8 chick embryos are used in this study. Human embryos are analyzed by reconstruction of serial section slides and chick embryos are microdissected and examined by scanning electron microscopy. In the early cardiac development (Streeter horizon 12), bulbo-ventricular fold divided two ventricles first. The atrioventricular canal is incompletely divided and the canal was in contact neither with septum primum nor with ventricular septal crest. Infundibular and truncal septa were not seen. The division of A-V canal was observed during the stages 14-15. Septation of truncus arteriosus (Streeter horizon 15-17) was followed by septation of bulbus cordis (Streeter horizon 16-17). The shortening of mitral-aortic distance and downward left shift of aortic valve occured after the trunco-infundibular septation and finally the secondary interventricular formen closed at the end of seventh week (Streeter horizon 20-21).
Humans ; Chick Embryo ; Animals

No abstract available.
Animals ; Chick Embryo* ; Nicotine*

In this study, we report that the treatment of strychinine (STR), an inhibitor of glycine receptor, induced premature onset of programmed cell death (PCD) of developing chick motoneurons (MNs). Treatment of STR on E4 chick embryo increased the apoptosis of MN on E5 when MN PCD does not occur normally. On the other hand, treatment of STR from E3 or E5 for 24 hours did not significantly influence the extent of MN PCD, indicating that the STR effect is developmental stage-specific. However, the expression of glycine receptor isoform was low on E3-4, and other glycine receptor antagonists did not exhibit PCD-promoting activity, suggesting that the STR action on PCD is not related to the glycine receptor activation. Identification of the target molecule for STR action may provide novel mechanism how the onset of developmental PCD is regulated.
Animals ; Apoptosis ; Cell Death ; Chick Embryo ; Glycine ; Hand ; Receptors, Glycine

OBJECTIVETo explore the essential features of the potential distribution of electrocardiac field.

METHODSThe ECGs of 60 hearts of 5-day chick embryos were immersed in normal saline solution or distilled water and their different conductivities were recorded at 5 points at different distances in 4 directions perpendicular to each other. Comparison of the form and amplitude of ECGs was made between every two points with the same distance to the heart in 2 opposite directions to determine the potential distribution of the electrocardiac field of the one-chambered heart.

RESULTSThe ECGs recorded at every 2 points in 2 opposite directions with the same distance to the heart immersed in the same liquid medium were both upper standing, with no significant different between their amplitude of R(r) wave (P > 0.05).

CONCLUSIONThe uniform outward potential distribution of the electrocardiac field might not represent the form of depolarization but that of sphere-like and single-source when the influence of different reference points and thickness of different chamber walls upon mapping of body surface is excluded.

OBJECTIVE: To determine whether there is a re-closure capacity of the open neural tube defect(ONTD) and to characterize its re-closing process, the morphological changes and the re-closure rate of a surgically induced ONTD are examined chronologically in early chick embryos. METHODS: Embryos of Hamburger and Hamilton stage 18-19 were used. The posterior roof of the central canal in the closed neural tube was incised longitudinally at the wing bud level. The incision was 3 somites long, which was equivalent to approximately 0.8mm. Following surgery, the embryos were re-incubated in ovo for three or five days. The area of the incision was observed with a stereomicroscope. Some of them were examined histologically with the transverse section of the wing bud area. They were divided into two groups(POD 3 and POD 5) according to the re-incubation period at the time of sacrifice and then into two subgroups(re-closure and defect group) according to the presence of ONTD at the operative site. RESULTS: The results showed : 1) Re-closure of ONTD occurred in 58%(23/40) of POD 3 embryos and 46%(22/48) of POD 5 embryos. The difference of re-closure was not statistically significant. 2) Most of the re-closed neural tubes revealed no significant difference from the controls in the histological examination. 3) In POD 3 and 5 groups, there was a tendency of zipper-like fusion in both re-closure and defect groups. CONCLUSION: The results of study showed that the neural tube of the early chick embryo has a re-closure capacity after being surgically reopened. Seemingly, re-closure occurs mainly before POD 3 and progresses from the ventral to the dorsal part of the neural tube. The mechanism of re-closure needs to be investigated further.
Animals ; Chick Embryo* ; Embryonic Structures ; Neural Tube Defects* ; Neural Tube* ; Somites ; Wings, Animal

Over the past few years, considerable progress has been achieved about the extracellular elements and intracellular regulatory molecules that are involved in the regulation of chondrogenesis. However, little is known about the molecular mechanism of how these molecules influence the gene activities during cartilage differentiation. Recently we isolated a Chicken Cartilage derived Matrix Protein (CCMP 10), a novel protein, from chicken prechondrogenic mesenchyme. To further understand the function of CCMP-10 in cartilage development, we investigated the expression of CCMP-10 during the prechondrocyte differentiation in chick embryos and micromass cultured prechondrogenic cells, using a variety of methods such as transient transfection of CCMP 10, immunohistochemical localization, northern analysis, and western analysis. When transiently transfected, CCMP 10 was expressed in both nucleus and cytoplasm, with stronger intensity in the nucleus. In an immunohistochemical study, CCMP 10 was expressed in prechondrogeinc mesenchymal cell, perichondrium, and resting and proliferative zone of the growth plate of long bone, while no expression of CCMP 10 was observed in upper mature chondrocytes and hypertrophic chondrocytes. Northern analysis of micromass cultured prechondrogenic cells showed the expression of CCMP-10 mRNA for first 2 days, while Col 2a1, aggrecan, and CMP mRNAs, known genes to express in mature chondrocyte, initiated the expression at day 2 and continued to express by day 5. In western analysis, CCMP-10 was detected at initial stage and continued to express by day 3, while Col 2al protein began to express only one day after, and continued to express. Taken together, our data suggest that CCMP-10 may play a significant role in the early cartilage development.
Aggrecans ; Animals ; Cartilage* ; Chick Embryo ; Chickens* ; Chondrocytes ; Chondrogenesis* ; Cytoplasm ; Growth Plate ; Mesoderm ; RNA, Messenger ; Transfection

OBJECTIVE: To investigate a re-closure capacity and chronological changes of re-closure, the histologic findings are observed after skin graft on surgically induced spinal open neural tube defect(ONTD) in chick embryos. METHODS: Embryos were divided into two groups: graft and control. In the embryos of the graft, a skin fragment from another chick embryo of embryonic day 7 was grafted on the ONTD immediately after neural tube incision. Embryos were re-incubated in ovo, up to postoperative days(PODs) 3, 5, 7, 10 and sacrificed. Rate of re-closure was compared according to the group of the embryo and the observation time point. Serial changes in histological appearance were observed to investigate whether the re-closured ONTDs regain normal shape. Statistical analysis was performed using the SAS and x2 test. RESULTS: On PODs 3, 5, 7, and 10, re-closure rates of the graft were 87, 60, 53 and 88%, and those of the control were 13, 0, 0 and 20%, respectively. They showed more frequent re-closure of ONTDs by the skin allograft in the graft than control. There was no statistical difference between the closure rates of adjacent POD subgroups. Some embryos of the closed groups revealed complete closure of the neural tube and there was no difference from the normal neural tube. CONCLUSION: Skin graft on the surgically induced ONTD in the embryonic period has a protective effect on the spinal cord. It is suggested that the prenatal skin graft on the lesions of fetal myelomeningocele might prevent repeated spinal cord damage.
Allografts ; Animals ; Chick Embryo* ; Embryonic Structures ; Meningomyelocele ; Neural Tube Defects* ; Neural Tube* ; Skin* ; Spinal Cord ; Transplants*

For the experimental study of neural tube defect (NTD), a surgical model has advantages over other models in a few aspects. It causes less functional derangement of cells and the NTDs can be made selectively by surgery. The authors planned to use the surgical model for the experimental study of NTD. As the first step for the studies, the chronological changes of morphology during the early postoperative period were investigated using postincubation 3-day chick embryos. The objectives of this study are (1) the morphological evaluation of the surgical model as a method for studies of open NTD, and (2) the observation of morphological changes for the first 24 hours after surgery which include 'overgrowth' appearance and the continuity between the surface ectoderm and the neuroectoderm. The morphological changes were observed by light microscope and scanning electron microscope. Immediately after surgery, typical open NTDs were observed. Morphologically they were very similar to the appearance of spontaneous (non-surgical) open NTDs. The opened neural tubes were everted progressively and they looked rather flat at 24 hours after surgery. Cellular hyperplasia ('overgrowth' appearance) was noted within 24 hours after surgery and became more prominent during the 24 hours. There was increasing continuity between the surface ectoderm and the neural tissue until 24 hours after surgery when the continuity looked almost complete. In conclusion, surgically induced NTDs are morphologically very similar to spontaneous NTDs.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals ; Chick Embryo ; *Disease Models, Animal ; Evaluation Studies as Topic ; Neural Tube Defects/etiology/*pathology ; Postoperative Period

Animals ; Chick Embryo ; physiology ; Electrocardiography ; methods ; Heart ; embryology ; physiology ; Heart Rate ; physiology

AIMTo investigate the effect of morphine on fetal movement, heart rate, hatch weight, hatch days and hatch rate.

METHODSMorphine was injected into airspace of eggs and fetal movement, heart rate, hatch weight, hatch days and hatch rates were recorded.

RESULTSHatch days were shorter, hatch rates were lower and some chicks became motor disorder for morphine. Chicks with morphine exposure 20 mg/kg from E 12 to E 16 had highest hatch rate and lowest disable rate. Morphine reduced fetal movement, increased heart rate (P < 0.05).

CONCLUSIONThe development of chick embryo is impaired by morphine exposure and the magnitude of these effects depends on the drug dose and the length of time that the developing organism is exposed to morphine.