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Biomedical subjects

A Weiland

Publications and source records attributed to A Weiland.

15 recordsLinked to original sources
PubMed1995

Immunolocalization and expression of bone morphogenetic proteins 2 and 4 in fracture healing.

Recently, it has become increasingly evident that fracture healing involves a complex interaction of many local and systemic regulatory factors. The roles of some of these growth factors have been described; however, little is understood about the presence of the bone morphogenetic proteins in fracture repair, despite the fact that they are the most potent osteoinductive proteins known. This study defines and characterizes the physiologic presence, localization, and chronology of the bone morphogenetic proteins in fracture healing with an established rat fracture healing model. With use of a recently developed monoclonal antibody against bone morphogenetic proteins 2 and 4 developed with standard avidin-biotin complex/immunoperoxidase protocols, frozen undecalcified fracture calluses were analyzed semiquantitatively for the percentage of various types of fracture cells staining positively. During the early stages of fracture healing, only a minimum number of primitive cells stained positively in the fracture callus. As the process of endochondral ossification proceeded, the presence of bone morphogenetic proteins 2 and 4 increased dramatically, especially in the primitive mesenchymal and chondrocytic cells. While the cartilaginous component of the callus matured with a concomitant decrease in the number of primitive cells, there was a concomitant decrease in both the intensity and the number of positively staining cells. As osteoblasts started to lay down woven bone on the chondroid matrix, these osteoblastic cells exhibited strong positive staining. The intensity of this staining decreased, however, as lamellar bone replaced the primitive woven bone. A similar observation was noted for the areas of the callus undergoing intramembranous ossification. Initially, within several days after the fracture, periosteal cells and osteoblasts exhibited intense staining for bone morphogenetic proteins 2 and 4. As the woven bone was replaced with mature lamellar bone, this staining decreased. These data, and the awareness of the strong osteoinductive capacities of bone morphogenetic protein, suggest that bone morphogenetic proteins 2 and 4 are important regulators of cell differentiation during fracture repair.

Animals↗
PubMed1992

Simple method for correcting total protein in plasma for actual fibrinogen content.

Using plasma instead of serum for routine chemistry analyses has many advantages. To overcome the disadvantage of inclusively measuring fibrinogen in the plasma total protein assay without changing the clinical significance of the total protein assay, we investigated the possibility of subtracting the actual amount of fibrinogen from the plasma total protein. The correlation between serum and plasma total protein was excellent (plasma total protein = 0.989 x serum total protein + 6.7 g/L; r = 0.969; n = 131; mean difference = 5.55 g/L; P < 0.001). When the plasma total protein was corrected for the actual amount of fibrinogen, the correlation with serum total protein was equally good but the intercept was practically eliminated (corrected plasma total protein = 1.009 x serum total protein + 0.25 g/L; r = 0.985; n = 131; mean difference = 0.78 g/L; P = 0.47). The mean concentration of fibrinogen was 2.5 g/L (range: 1.38-3.62 g/L; n = 404) for blood donors, 3.6 g/L (n = 2707) for patients from the outpatient department, 4.6 g/L (n = 2023) for patients admitted to the hospital, and 6.6 g/L (n = 219) for patients whose concentration of C-reactive protein was > 50 mg/L. We conclude that the plasma total protein result should be corrected for the actual amount of fibrinogen.

Blood Proteins↗
PubMed1991

The healing of facial bone fractures by the process of secondary union.

The mechanism of healing of facial bone fractures was investigated in a rabbit model. Twelve New Zealand white rabbits underwent surgically induced fractures of the right infraorbital rim and fracture ostectomies (4 to 5 mm) of the left infraorbital rim. Animals were sacrificed 2, 4, and 8 weeks postfracture. Bone, including periosteum, obtained from each fracture or fracture osteoctomy site was divided longitudinally for hematoxylin and eosin staining, fluorescent microscopy, microangiography, and microradiography. Sequential fluorochrome labels of oxytetracycline (30 mg/kg), alizarin complexone (30 mg/kg), DCAF (20 mg/kg), and xylenol orange (90 mg/kg) were administered 24 hours preoperatively and at 1, 2, 4, and 8 weeks postfracture. All fracture and fracture ostectomy sites demonstrated vascular ingrowth, mineralization, and woven bone formation by 2 to 4 weeks postoperatively, beginning with a cartilage precursor. Subsequently, the woven bone was replaced with remodeled lamellar bone, resulting in complete bony healing by 8 weeks postoperatively. These steps were substantiated by microscopic, microradiographic, and radiologic examination of the specimens. This study demonstrates that fractures of the facial bones in a rabbit model heal by a process of new bone formation that resembles secondary union in endochondral bones.

Animals↗
PubMed1976

External stabilization of a replanted upper extremity: case report.

A case replantation of the upper extremity is presented using external fixation as the method to achieve bony stability. Although internal fixation may remain the method of choice for stabilization of a replanted limb, external fixation can also provide bony stability where more conventional methods are not applicable.

Adult↗