PubMed Health⌕ Search

Biomedical subjects

K E Chapman

Publications and source records attributed to K E Chapman.

42 records · Page 3Linked to original sources
PubMedDate not supplied

Formation of microscale gradients of protein using heterobifunctional photolinkers.

Gradients of biological molecules on a microscale have been postulated to elicit cellular responses, such as migration. However, it has been difficult to prepare such gradients for experimental testing. A means for producing such gradients has been developed using a heterobifunctional photolinking agent with laser light activation. The photolinking agent synthesized includes an N-hydroxysuccinimide group and a photoreactive benzophenone (BP) separated by a tetraethylene glycol (TEG) spacer. The presence of the tetraethylene glycol spacer renders the photolinker hydrophilic, a desirable trait for conjugation in aqueous solutions. The linker was then conjugated to R-phycoerythrin (R-PE), a fluorescent protein. The resulting photolinker-R-phycoerythrin conjugate (BP-TEG-PE) was then immobilized onto a polystyrene surface by laser irradiation on a motorized stage. By varying exposure time of the sample to the beam, the amount of BP-TEG-PE immobilized on the surface was changed over an order of magnitude over a distance of 250 microns. This method can be applied to prepare gradients of proteins that elicit biological responses, such as extracellular matrix proteins or growth factors, and to study the biological effects of such gradients.

Alanine↗
PubMedDate not supplied

Nasopharyngeal carcinoma: a 15-year retrospective study.

Malignancy in the nasopharynx, although uncommon, is potentially devastating because of the anatomy of the region and benign early symptoms, which result in infrequent early diagnosis. High-dose radiation therapy, with fields including the oral structures, is the treatment of choice and may result in significant oral complications. This paper reviews 39 cases of nasopharyngeal carcinoma diagnosed at the University of North Carolina Hospitals over a 15-year period. Patient demographics, histopathology, presenting signs and symptoms, stage at diagnosis, possible risk factors, treatment modalities, survival, side-effects of therapy, and dental intervention are reported.

Adolescent↗