No abstract available.
Blood Group Antigens* ; Humans

No abstract available.
Blood Group Antigens* ; Humans

No abstract available.
Ligaments* ; Magnetic Resonance Imaging* ; Tendons* ; Transplants*

Tooth movement by orthodontic force is based upon alveolar bone resorption at compression site and bone formation at tension site of tooth. The function of cyclic AMP is to participate not only in initial action of bone cells by mechanical forces but also in the continuous cellular response leading, to bone remodeling. This experiment was performed to clarify the role of cyclic AMP in bone remodeling by mechanical forces. The orthodontic forces of about 80 gm and 100 gm were applied to the right canines of maxillary and mandibular bone, respectively, in cats, treated for periods of time ranging from one hour to 28 days. Alveolar bones were obtained from compression and tension sites . surrounding tipping maxillary and mandibular canines as well as from contralateral control sites. The samples were extracted, boiled and homogenized, and the supernatants were assayed for cyclic AMP by a radioimmunoassay mothod. The results were as follows: 1. The orthodontic movement of canines was increased to the end of experimental period and the action of orthodontic forces on tooth movement was more effective in maxillary canine. 2. The cyclic AMP levels of alveolar bones in compression and tension sites initially decreased, then increased and remained elevated to the end of experiment. The differences of the cyclic AMP levels between treated sites and non-treated sites were gradually increased. 3. The cyclic AMP levels in treated sites of mandibular alveolar bone was higher than that of maxillary alveolar bone.
Animals ; Bone Remodeling ; Bone Resorption ; Cats ; Cyclic AMP* ; Osteogenesis ; Radioimmunoassay ; Tooth ; Tooth Movement

No abstract available.
Vincristine*

No abstract available.
Cardiac Tamponade* ; Leukemia, Myeloid, Acute*

No abstract available.

No abstract available.
Constriction, Pathologic* ; Neurologic Manifestations* ; Spinal Canal*

No abstract available.
Head* ; Magnetic Resonance Imaging* ; Necrosis*

OBJECTIVES: The myelodysplastic syndromes (MDS) are a group of acquired clonal hematopoietic disorders characterized by peripheral cytopenias and a hypercellular or normocellular dysplastic bone marrow. The mechanisms responsible for development of MDS are not known. We performed this study to evaluate the hematopoietic abnormalities and apoptosis in MDS. METHODS: Long-term bone marrow culture (LTBMC) was performed for colony assays, cobblestone area assay, stromal morphologic changes from 7 patients with MDS and 7 normal controls. In situ nick end labeling (ISNEL) method was performed for detection of apoptosis from LTBMC in 7 patients with MDS and 7 normal controls. ISNEL method also performed in bone marrow cell bloc samples in 36 patients with MI3S. RESULTS: Viability of nonadherent cells from LTBMC of patients with MDS was not decreased compared with normal controls at 1 week, but significantly decreased at 2 and 3 weeks compared with normal controls (P<0.0001). Formation of the cobblestone areas from patients with MDS was slightly decreased compared with normal controls at 1st week, but significantly decreased at 2nd and 3rd weeks compared with normal controls (P<0.0001). Slightly decreased compared with normal controls at 1 week, but significantly decreased at 2 and 3 weeks compared with normal controls (P<0.0001). Stromal layers produced in LTBMC of normal controls and 1 patient with MDS were detected at 1 week and were formed confluent stroma from 3 weeks, but another patients with MDS who did not form a confluent stroma. Patients with MDS had significantly lower colony forming unit granulocyte-macrophage (CFU-GM) compared with normal controls at 1 (P<0.01) and 2 weeks (P<0.001) of LTBMC. Two weeks of LTBMC resulted more profound inhibition of CFU-GM formation than 1 week (P<0.0001). Apoptotic cell death was absent in adherent and non adherent cells from normal controls at 1 and 2 weeks, but massive apoptotic cell death was found in adherent and non adherent cells from patients with MDS at 1 and 2 weeks and the degree of apoptosis was profound at 2 weeks compared with 1 week. Among the 36 patients, fifteen patients demonstrated varying degrees of apoptosis positive cells, 4 having low, 8 intermediates, and 3 high scores. Remaining 21 patients showed absent apoptosis or only occasional positive cells. CONCLUSION: Hematopoietic abnormalities such as a failure of differentiation are caused by the stromal defects and the biologic basis of the apparent paradox of peripheral cytopenias in the face of hypercellular (or normocellular) marrow is related by intramedullary apoptotic cell death of the stromal and hematopoietic cells.
Apoptosis* ; Bone Marrow Cells ; Bone Marrow* ; Cell Death ; Granulocyte-Macrophage Progenitor Cells ; Humans ; In Situ Nick-End Labeling* ; Myelodysplastic Syndromes* ; Stem Cells