Glycine 119 of bovine growth hormone is critical for growth-promoting activity.

Bovine GH (bGH) analogs with single amino acid substitutions at positions 117 (bGH-E117L), 119 (bGH-G119R), and 122 (bGH-A122D) were generated. These analogs bind to mouse liver membrane preparations with affinities similar to native bGH. However, transgenic mice which express the analogs demonstrate different phenotypes ranging from dwarfism to gigantism. For example, expression of bGH or bGH-E117L result in large transgenic mice. In contrast, transgenic mice with a growth phenotype similar to nontransgenic animals result from expression of bGH-A122D. Surprisingly, transgenic mice with relatively high serum levels of bGH-G119R possessed a dwarf phenotype. Together these results suggest that Gly 119 and Ala 122 are involved in growth-promoting activity of GH.

Solid modeling of human vocal tract using magnetic resonance imaging and acoustic pharyngometer.

This investigation uses a multi disciplinary approach to standardize a non-invasive method for measuring human vocal tract morphology. A series of magnetic resonance imaging (MRI) scans are performed on the subject's vocal tract and a detailed three-dimensional model is created through image processing and computer modeling. The area and volume obtained from the solid model is compared with that obtained from the Eccovision acoustic pharyngometer. This establishes the accuracy of the solid model. The model is then used to develop other specific models through parametric modeling. This method is useful in creating solid models with limited geometrical information and helps researchers study the human vocal tract changes due to aging and degenerative diseases.

Comparison of image processing techniques (magnetic resonance imaging, computed tomography scan and ultrasound) for 3D modeling and analysis of the human bones.

Magnetic resonance imaging (MRI), computed tomography scanning (CT scan), and ultrasound imaging techniques (UI) were used for data acquisition to construct/develop a 3D solid model of the human tibia, femur, and skull. CT scan was found to be an acceptable technique for cadavers. CT scans are harmful to the human body in large doses, while MRIs and ultrasound are known to be safe. However, MRIs form a better tool in performing this image generation task for living beings because of its high resolution capacity when compared with images obtained using ultrasound techniques. High resolution poses to be a very important factor, as the consideration of various material properties of the bones was part of the emphasis of this research. MRIs have the capacity of displaying a distinct boundary between the muscles and the bone, in addition to the boundary between the cortical and the cancellous region within the bone. Ultrasound was found to be the cheapest technique and gave reasonably good results for just the outside boundaries of the bone. The models of the human bones were generated on a Computer Aided Design (CAD) system. The cross-sections obtained from (MRI, CT, or UI) were scanned into the computer. Image processing software was used to detect the boundaries of the bones. A C + + program was used to read the coordinates of the edges and construct a B-spline curve on the CAD system. The curves were converted to a B-rep solid using skinning. The solid models were meshed, constrained, and material properties were assigned to different regions of the models for Finite Element Analysis (FEM).