Morphological and embryological characteristics of bronchial arteries in the rat

There have been no previous reports of detailed macroscopic findings of the bronchial arteries, the nutrial vessels of the lungs. Also, previously, very little was known about the developmental processes of the bronchial arteries in rats and other laboratory animals. In the present study, we dissected bronchial arteries of adult rats from their origin to the pulmonary hilus, and examined developmental processes of bronchial arteries in a series of rat embryos. We observed one right bronchial artery and one left bronchial artery. The right artery arose from the right highest intercostal artery, ran together with the right vagus nerve along the right side of the trachea and right principal bronchus and reached the pulmonary hilus. The left artery arose from the left internal thoracic artery, ran along the left vagus nerve on the ventral surface of the thoracic aorta, and reached the dorsal surface of the left principal bronchus. In a series of 12 to 20.5-day-old rat embryos, the right bronchial artery was clearly identified in 20.5, 18.5, and 16.5-day-old embryos. In a 15.5-day-old embryo, a vessel corresponding to the right bronchial artery was recognized within the capillary plexus extending along the right lateral surface of the bronchus. In ontogenetic development, there appears to be little difference in completion time of the extrapulmonary part of the bronchial arteries between humans and rats.     

A microcoagulator for embryological research

Research on the interdependence between different congenital malformations in one subject is closely dependent on suitable methods. In order to approach the problem experimentally, microcoagulations in the chicken embryo seemed useful. The use of a microelectrode (10 μm tip diameter) for electrocoagulation with an alternating current of 1·2 MHz frequency appeared to be optimal for the induction of lesions of about 50 μm diameter in a selected part of the young embryo. For this purpose, a constant-current source with a preset timer was constructed, which allows measurement of the coagulation time and the current required for coagulation of the albumin under study, as well as consecutive reproduction of these values for coagulation in the embryo.     

Right gonadal arteries passing dorsally to the inferior vena cava: embryological hypotheses

The right gonadal artery (RGA) usually arises from the anterior wall of the abdominal aorta below the level of the renal arteries and veins, passes ventrally to the inferior vena cava (IVC), and then runs obliquely downward to reach the pelvic cavity. In this study, we observed 59 Japanese cadavers and found that in eight of them (13.6%), the RGA’s passed dorsally to the IVC. Together with the various courses of RGAs reported in the literature, we here divided the courses into four subtypes, due to the relationship to the left renal vein and the IVC, of superior, middle and lower types (L1 = ventrally, L2 = dorsal of IVC). Superior type was seen in 3.6%. Lower types were fount to in the most cases (L1: 83.5%, L2: 13.6%). The middle type was not realized. The classification of this variations make it easy to describe the RGA’s passing below the level of the left renal vein. RGA can pass either ventrally or dorsally to the IVC. RGAs passing at or above the level of the left renal vein run dorsally but not ventrally to the IVC. The variations in the origin, course and branching of RGAs are attributed to development of the IVC.     

A computerised technique for morphometry and 3D reconstruction of embryological structures

Summary In the last decade we have witnessed the development of software technology capable of image analysis and morphometry [1, 8–12]. Although these methods are sometimes difficult to master in a practical sense, they are tremendously efficient and precise when applied to the study and measurement of developing biological structures, particularly in the field of embryology. In this study we describe the application on human embryos of an image analyzing system that enables one to perform quantitative analyses of the morphology and size of developing organs and structures as well as their ultimate three-dimensional reconstruction (3DR).

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Technique informatique de morphométrie et de reconstruction tridimensionnelle des structures embryonnaires

Résumé Au cours de cette dernière décennie nous avons assisté au développement de logiciels adaptés à l'analyse de l'image et à la morphométrie. Bien que ces techniques soient parfois difficiles à maîtriser, elles sont particulièrement efficaces et précises dans l'étude du développement des structures biologiques, et particulièrement dans le domaine de l'embryologie. Dans ce travail, nous rapportons l'application aux embryons humains d'un système d'analyse d'image, qui autorise aussi bien une analyse morphologique quantitative des organes et des structures en développement, que leur reconstruction tridimensionnelle ultérieure.

     

An in vitro model for characterizing the post-migratory cranial neural crest cells of the first branchial arch.

The cranial neural crest (CNC) is a transient cell population that originates at the crest of the neural fold and gives rise to multiple cell types during craniofacial development. Traditionally, researchers have used tissue explants, such as the neural tube, to obtain primary neural crest cells for their studies. However, this approach has inevitably resulted in simultaneous isolation of neural and non-neural crest cells as both of these cells migrate away from tissue explants. Using the Wnt1-Cre/R26R mouse model, we have obtained a pure population of neural crest cells and established a primary CNC cell culture system in which the cell culture medium best supports the proliferation of E10.5 first branchial arch CNC cells and maintains these cells in their undifferentiated state. Differentiation of CNC cells can be initiated by switching to a differentiation medium. In this model, cultured CNC cells can give rise to neurons, glial cells, osteoblasts, and other cell types, faithfully mimicking the differentiation process of the post-migratory CNC cells in vivo. Taken together, our study shows that the Wnt1-Cre/R26R mouse first branchial arch provides an excellent model for obtaining post-migratory neural crest cells free of any mesodermal contaminants. The cultured neural crest cells are under sustained proliferative, undifferentiated, or lineage-enhanced conditions, hence, serving as a tool for the investigation of the regulatory mechanism of CNC cell fate determination in normal and abnormal craniofacial development.     

A bilinear stress-strain relationship for arteries

A comprehensive understanding of the mechanical properties of blood vessels is essential for vascular physiology, pathophysiology and tissue engineering. A well-known approach to study the elasticity of blood vessels is to postulate a strain energy function such as the exponential or polynomial forms. It is typically difficult to fit experimental data to derive material parameters for blood vessels, however, due to the highly nonlinear nature of the stress-strain relation. In this work, we generalize the strain definition to absorb the elastic nonlinearity and then propose a two-dimensional bilinear stress-strain relation between second Piola-Kirchhoff stress and the new strain measure. The model is found to represent the Fung's exponential model very well. The novel linearized constitutive relation simplifies the determination of material constants by reducing the nonlinearity and provides a clearer physical interpretation of the model parameters. The limitations of the constitutive model and its implications for vascular mechanics are discussed.     

Global sensitivity analysis of a wave propagation model for arm arteries

Wave propagation models of blood flow and blood pressure in arteries play an important role in cardiovascular research. For application of these models in patient-specific simulations a number of model parameters, that are inherently subject to uncertainties, are required. The goal of this study is to identify with a global sensitivity analysis the model parameters that influence the output the most. The improvement of the measurement accuracy of these parameters has largest consequences for the output statistics. A patient specific model is set up for the major arteries of the arm. In a Monte-Carlo study, 10 model parameters and the input blood volume flow (BVF) waveform are varied randomly within their uncertainty ranges over 3000 runs. The sensitivity in the output for each system parameter was evaluated with the linear Pearson and ranked Spearman correlation coefficients. The results show that model parameter and input BVF uncertainties induce large variations in output variables and that most output variables are significantly influenced by more than one system parameter. Overall, the Young's modulus appears to have the largest influence and arterial length the smallest. Only small differences were obtained between Spearman's and Pearson's tests, suggesting that a high monotonic association given by Spearman's test is associated with a high linear corelation between the inputs and output parameters given by Pearson's test.     

Origin of the torus mandibularis: An embryological hypothesis

Torus mandibularis, a well‐known protuberance in the dental field, has been defined as a hyperostosis in the lingual aspect of the body of the mandible above the mylohyoid line. However, the origin of the torus mandibularis has not yet been clarified. The aim of this study was to provide a better understanding on the origin of the torus in view of the specific development of Meckel's cartilage at the site corresponding to the adult torus. A total of 40 mid‐term human fetuses at 7–16 weeks of gestation were examined. The 10–13 weeks stage corresponded to the critical period in which Meckel's cartilage with endochondral ossification underwent a bending at the beginning of the intramandibular course. At the level of mental foramen, which was located between the deciduous canine and the first deciduous molar germs, the medial lamina of the mandible protruded medially to reach Meckel's cartilage. Thus, the medial lamina covered the posterior and superior aspect of the bending Meckel's cartilage just above the attachment of the developing mylohyoid muscle (i.e., in the oral cavity). We considered a bony prominence, which composed the protruding medial lamina and the bending Meckel's cartilage as the fetal origin of the torus mandibularis. A new theory is proposed for the origin of the torus mandibularis based on the existence of an anlage formed during the development of the mandible, variable in morphology and size, but always constant. Clin. Anat. 26:944–952, 2013. © 2013 Wiley Periodicals, Inc.     

Model for the functional instruction of swallowing

It is difficult to teach students about the mechanism of swallowing. There are three phases of swallowing; oral phase, pharyngeal phase and esophageal phase. The bolus of food is propelled to back of mouth by the tongue and the swallowing reflex happens. After nasopharynx and mouth closure, the glottal closure occurs, then hyoid and larynx are lifted by the contractions of suprahyoid and thyrohyoid muscles. As for the epiglottis, it is compressed by the tongue and inclines downward. As the larynx is lifted upward and anteriorly, slight vacuum is caused in the lower pharynx and upper esophagus at the same time, and pharyngeal constrictor compress bolus, therefore, the bolus passes the piriform fossa, and is inhaled into the esophagus. This time, we made a model in order to explain this complicated mechanism. The mandible is made of paper clay by using a metallic plate in it. The tongue, the soft palate, and the epiglottis are made by using the EVA (Ethylene Vinyl Acetate) sheet. Styloglossus, suprahyoid, thyrohyoid muscles are made with the wire. Moreover, a movable wooden chip represents the contraction of the pharyngeal constrictor muscles. The spring is put in the trachea in order to lift the larynx. The upper part of esophageal constrictor is made with spring plates.     

A return to a dedicated machine for computer-assisted instruction

Advances in computer technology have made it technically and economically feasable to produce a self-contained interactive computer terminal. A programming system called PILOT 73 will utilize the built-in minicomputer and carry out computer-assisted instructional programs with students. Comparisons are made between this dedicated system and the more traditional time-sharing multi-terminal computer system normally used for computerized instruction.     

A course of instruction for women with irritable bowel syndrome

ObjectiveThe aim of this study was to determine the effects a course of instruction about irritable bowel syndrome (IBS) might have on symptoms, psychological well-being, and medical care requirements in these patients.MethodsTwenty-nine women with IBS participated in a programme of instruction on medical care, physical activity, stress-management, diet and health insurance. The women completed the Gastrointestinal Symptom Rating Scale and the Psychological General Well-Being Index and provided information about their requirements of medical care before and after the course.ResultsTwenty-three of the women included, completed the questionnaires at 12 months after the course. When comparing these values to those at baseline, there were improvements in abdominal pain (p < 0.037) and vitality (p < 0.045) as well as a reduction in the number of visits to physicians (p < 0.037) and dieticians (p < 0.042).ConclusionInformation related to the disease, might help women with IBS to perceive less pain and more vitality and thereby experience a higher quality of life.Practice implicationsA course of instruction for patients with IBS may be of benefit for the patients, and could be a part of a multicomponent approach in the treatment of this patient group.     

A case of second branchial cleft cyst with oropharyngeal presentation

Second branchial cleft cysts are the most common type of branchial abnormalities and usually found high in the neck. Oropharyngeal presence of branchial cleft cyst is very rare. We report a case of oropharyngeal branchial cleft cyst in 2-yr-old girl with about 1 x 1 cm sized cystic mass, which had not any specific symptom. It was removed completely under impression of mucocele and did not have tract-like structure. However, cyst had a squamous epithelium-lined wall with lymphoid aggregation in histopathologic study, which was characteristic finding of branchial cleft cyst. Patient discharged without any complication and there was no evidence of recurrence for 18 months follow-up. We review reported oropharyngeal or nasopharyngeal presentation of these cases in English literature and embryological explanation.     

Dose model for stent-based delivery of a radioactive compound for the treatment of restenosis in coronary arteries

Radiolabeled drug-eluting stents have been proposed recently as a novel method to potentially reduce restenosis in coronary arteries. A P-32 labeled oligonucleotide (ODN) loaded on a polymer coated stent is slowly released in the arterial wall to deliver a therapeutic dose to the target tissue. However, the relatively low proportion of drugs transferred to the arterial wall (<2%-5% typically) raises questions about the degree to which radiolabeled drugs eluted from the stent can contribute to the total radiation dose delivered to tissues. A three-dimensional diffusion-convection transport model is used to model the transport of a hydrophilic drug released from the surface of a stent to the arterial media. Large drug concentration gradients are observed near the stent struts giving rise to a nonuniform radiation activity distribution for the drug in the tissues as a function of time. A voxel-based kernel convolution method is used to calculate the radiation dose rate resulting from this activity build-up in the arterial wall based on the medical internal radiation dose formalism. Measured residence time for the P-32 ODN in the arterial wall and at the stent surface obtained from animal studies are used to normalize the results in terms of absolute dose to tissue. The results indicate that radiation due to drug eluted from the stent contributes only a small fraction of the total radiation delivered to the arterial wall, the main contribution coming from the activity that remains embedded in the stent coating. For hydrophilic compounds with rapid transit times in arterial tissue and minimal binding interactions, the activity build-up in the arterial wall contributes only a small fraction to the total dose delivered by the P-32 ODN stent. For these compounds, it is concluded that radiolabeled drug-eluting stent will not likely improve the performance of radioactive stents for the treatment of restenosis. Also, variability in the delivery efficacy of drug delivery devices makes accurate dosimetry difficult and the drug washout in the systemic circulatory system may yield an unnecessary activity build-up and dose to healthy organs.     

Familial branchio-oto-renal dysplasia: A new addition to the branchial arch syndromes

The present report concerns a two-generation family of nine individuals in which the father and three of the six living children all had: (1) a mixed hearing loss with a Mondini type cochlear malformation and stapes fixation; (2) cup-shaped, anteverted pinnae with bilateral prehelical pits: (3) bilateral branchial cleft fistulas; and (4) bilateral renal dysplasia and anomalies of the collecting system. The father and one affected son also had aplasia of the lacrimal ducts. A fourth child who died at 5 months of age was reported to have branchial cleft fistulas and bilateral polycystic kidneys at autopsy. In addition, the concept of noso-embryologic communities is presented. Such groups are composed of syndromes whose total phenotypic spectra not only overlap but also share common elements in embryogenesis. This concept is illustrated with a group of branchial arch syndromes that are related in this way.