Mediolateral somitic origin of ribs and dermis determined by quail-chick chimeras.
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Somites are transient mesodermal structures giving rise to all skeletal muscles of the body, the axial skeleton and the dermis of the back. Somites arise from successive segmentation of the presomitic mesoderm (PSM). They appear first as epithelial spheres that rapidly differentiate into a ventral mesenchyme, the sclerotome, and a dorsal epithelial dermomyotome. The sclerotome gives rise to vertebrae and ribs while the dermomyotome is the source of all skeletal muscles and the dorsal dermis. Quail-chick fate mapping and diI-labeling experiments have demonstrated that the epithelial somite can be further subdivided into a medial and a lateral moiety. These two subdomains are derived from different regions of the primitive streak and give rise to different sets of muscles. The lateral somitic cells migrate to form the musculature of the limbs and body wall, known as the hypaxial muscles, while the medial somite gives rise to the vertebrae and the associated epaxial muscles. The respective contribution of the medial and lateral somitic compartments to the other somitic derivatives, namely the dermis and the ribs has not been addressed and therefore remains unknown. We have created quail-chick chimeras of either the medial or lateral part of the PSM to examine the origin of the dorsal dermis and the ribs. We demonstrate that the whole dorsal dermis and the proximal ribs exclusively originates from the medial somitic compartment, whereas the distal ribs derive from the lateral compartment. (+info)
The effect of prolonged prednisone treatment on human costal cartilage.
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Costal cartilage (biopsy) from a 13-year-old boy receiving prolonged prednisone treatment (discontinuously from 2 6/12 to 13 11/12 years) for hepatosplenomegaly and lymphadenopathy has been studied and compared with costal cartilage from untreated individuals. Optical and electron microscopic studies including histochemistry have been employed. Chondrocyte degeneration characterized by lipidic material and glycogen in cells is enhanced following prednisone treatment. Acid proteoglycans are reduced in comparison to those in the untreated controls. Amianthoid (asbestoid) collagen fibers, derived from electron-dense bodies which represent remnants of degenerating chondrocytes, occur in all cartilages. A type of collagen similar to fibrous long-spacing collagen has been observed and is prominent in cartilage from the prednisone-treated individual. Evidence suggests that this type of collagen is cellular in origin and represents a transitional form of native collagen. Morphologic changes suggestive of aging are present following prolonged prednisone treatment. (+info)
Thixotropy of rib cage respiratory muscles in normal subjects.
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In this study, we searched for signs of thixotropic behavior in human rib cage respiratory muscles. If rib cage respiratory muscles possess thixotropic properties similar to those seen in other skeletal muscles in animals and humans, we expect resting rib cage circumference would be temporarily changed after deep rib cage inflations or deflations and that these aftereffects would be particularly pronounced in trials that combine conditioning deep inflations or deflations with forceful isometric contractions of the respiratory muscles. We used induction plethysmography to obtain a continuous relative measure of rib cage circumference changes during quiet breathing in 12 healthy subjects. Rib cage position at the end of the expiratory phase (EEP) was used as an index of resting rib cage circumference. Comparisons were made between EEP values of five spontaneous breaths immediately before and after six types of conditioning maneuvers: deep inspiration (DI); deep expiration (DE); DI combined with forceful effort to inspire (FII) or expire (FEI); and DE combined with forceful effort to inspire (FIE) or expire (FEE), both with temporary airway occlusion. The aftereffects of the conditioning maneuvers on EEP values were consistent with the supposition that human respiratory muscles possess thixotropic properties. EEP values were significantly enhanced after all conditioning maneuvers involving DI, and the aftereffects were particularly pronounced in the FII and FEI trials. In contrast, EEP values were reduced after DE maneuvers. The aftereffects were statistically significant for the FEE and FIE, but not DE, trials. It is suggested that respiratory muscle thixotropy may contribute to the pulmonary hyperinflation seen in patients with chronic obstructive pulmonary disease. (+info)
Surgical stabilization of traumatic flail chest.
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Since 1970 we have stabilized the ribs to correct paradoxical movement of the chest wall in chest injuries, using an original technique, in order to avoid as far as possible the need for long-term chest wall stabilization by intermittent positive pressure respiration (IPPR). The technical details of surgical stabilization are described, and the different types of stainless steel struts are shown. Type I was originally used either as an intramedullary nail or as an external brace. Types II and III were designed for external fixation of the strut to the rib. Treatment of 29 patients with severe flail chest, classified into four groups is shown: group I was treated by IPPR, group II by IPPR plus surgical stabilization, group III by surgical stabilization only, and group IV by surgical stabilization after exploratory thoracotomy. The clinical results are discussed. We conclude that surgical stabilization of the paradoxial movement of the chest wall can avoid the use of the respirator or at least reduce the interval of IPPR to a short period during the initial recovery from trauma. Using type III struts, we have obtained stabilization of the flail chest in all cases even in patients with severe anterior paradoxical movement. The patients' tolerance of surgical stainless steel struts was good. (+info)
Hemangioma of the rib: a case report.
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A case of hemangioma of the left seventh rib is presented. In January 1999, a 59-year-old woman presented with an enlarged costal mass which had been followed up for 4 years. Preoperative examination suggested chondrosarcoma because of tumor growth beyond the disrupted bony cortex. She underwent resection of the left seventh rib along with the sixth and seventh intercostal muscles and reconstruction of the chest wall defect. The pathological diagnosis of the lesion was hemangioma. She was discharged after an uneventful postoperative course. There has been no evidence of recurrence after a 14-month follow-up. Tumor growth beyond the disrupted bony cortex was a characteristic feature by both imagery and pathological examination in this case. This case represents a difficulty of a preoperative definite diagnosis of the chest wall tumors by imagery alone. (+info)
Loss- and gain-of-function mutations show a polycomb group function for Ring1A in mice.
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The products of the Polycomb group (PcG) of genes act as transcriptional repressors involved in the maintenance of homeotic gene expression patterns throughout development, from flies to mice. Biochemical and molecular evidence suggests that the mouse Ring1A gene is a member of the PcG of genes. However, genetic evidence is needed to establish PcG function for Ring1A, since contrary to all other murine PcG genes, there is no known Drosophila PcG gene encoding a homolog of the Ring1A protein. To study Ring1A function we have generated a mouse line lacking Ring1A and mouse lines overexpressing Ring1A. Both Ring1A(-/-)and Ring1A(+/-) mice show anterior transformations and other abnormalities of the axial skeleton, which indicates an unusual sensitivity of axial skeleton patterning to Ring1A gene dosage. Ectopic expression of Ring1A also results in dose-dependent anterior transformations of vertebral identity, many of which, interestingly, are shared by Ring1A(-/-) mice. In contrast, the alterations of Hox gene expression observed in both type of mutant mice are subtle and involve a reduced number of Hox genes. Taken together, these results provide genetic evidence for a PcG function of the mouse Ring1A gene. (+info)
The developmental fate of the rostral/caudal half of a somite for vertebra and rib formation: experimental confirmation of the resegmentation theory using chick-quail chimeras.
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To determine whether resegmentation of somites forms the axial skeleton, we traced the development of the rostral and the caudal half of a somite during skeletogenesis in chick-quail chimeras by replacing the rostral or caudal half of a newly formed chick somite with that of a quail somite. The rostral half-somite transplant formed the caudal half of the vertebral body, the entire spinous process and the distal rib, while the caudal half-somite transplant formed the rostral half of vertebral body, the rostral half of spinous process, the vertebral arch, the transverse process and the entire rib. These findings confirm the resegmentation theory except the spinous process and the distal rib. (+info)
Successful treatment of invasive aspergillosis in chronic granulomatous disease by granulocyte transfusions followed by peripheral blood stem cell transplantation.
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Chronic granulomatous disease (CGD) is a primary immunodeficiency disorder characterized by impaired microbial killing and susceptibility to bacterial and fungal infections. Cure of the disease can be achieved by stem cell transplantation when performed early in its course, and before severe infections have developed. Invasive aspergillosis constitutes a very high risk for transplantation. We report a 4-year-old boy with X-linked CGD who underwent successful HLA-identical peripheral blood stem cell (PBSC) transplantation during invasive pulmonary aspergillosis and osteomyelitis of the left fourth rib, which was unresponsive to antifungal treatment. During the 2 months prior to the transplant he received G-CSF-mobilized granulocyte transfusions (GTX) from unrelated donors three times a week in addition to the antifungal treatment. This resulted in clinical improvement in his respiratory status. He also received GTX during the aplastic period after the conditioning regimen, until he had engrafted. Post-transplant superoxide generation test revealed that neutrophil function was within normal range. One year post transplant the CT scan showed almost complete clearance of the pulmonary infiltrates and a marked improvement in the osteomyelitic process. Based on other reports and our own experience, GTX can serve as important treatment in patients with CGD who have failed conventional anti-fungal treatment and for whom stem cell transplantation is the only chance for cure. (+info)