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Biomedical subjects

R Leech

Publications and source records attributed to R Leech.

6 recordsLinked to original sources
PubMed2001

Medullomyoblastoma: case report.

This 7-year-old boy presented with a 2-week history of headache, nausea, vomiting, anorexia, lethargy, and unsteadiness of gait. Brain magnetic resonance imaging (MRI) revealed a cystic mass within the vermis of the cerebellum. A suboccipital craniectomy was performed to remove a tumor that contained primitive neuroectodermal cells with florid skeletal muscle differentiation. Immunohistochemical studies and electron microscopy confirmed the presence of both a primitive neuroectodermal component and rhabdomyoblastic differentiation, consistent with the diagnosis of medullomyoblastoma. This exceedingly rare tumor of the cerebellar vermis of children is characterized by two components: primitive neuroectodermal tumor cells and skeletal muscle. Although the histogenesis remains uncertain, advances in immunohistochemistry and electron microscopy suggest the origin of this tumor from a multipotential stem cell precursor.

Child↗
PubMed1994

Pediatric syringomyelia.

Syringomyelia was first recognized as a disease process some 400 years ago. The process of cystic dilation of the spinal cord is unpredictable and may result in a delay of many decades before the symptoms and signs of neurologic and orthopedic changes become apparent and commensurate with the observed cystic changes within the spinal cord. The syringomyelic process is usually associated with trauma, tumor, or congenital abnormalities at the craniocervical junction or along the spinal neuraxis. Several theories have been proposed as to processes involved in the development of spinal cyst formation, although none are completely compatible with the observed clinical pathology of syrinx development. Magnetic resonance imaging has markedly improved our ability to study the anatomy and natural history of syrinx formation, but to date, our understanding of the process remains imprecise. In view of the limited understanding of the pathophysiology of this disease process, it is not surprising that a variety of treatment regimens have been proposed and their efficacy remains difficult to fully evaluate.

Brain Diseases↗
PubMed1980

The deposition of Streptococcus sanguis NCTC 7868 from a flowing suspension.

Measurements were made of the rates at which continuously cultured Streptococcus sanguis NCTC 7868 cells accumulated on the inside surfaces of narrow glass capillaries from suspensions of the bacteria flowing down the capillaries at different velocities. Initially, the rate of accumulation of bacteria on the clean walls of the capillary was rapid. The deposition rate decreased with time, however, resulting in a saturation coverage of the glass surface which was considerably less than a monolayer. Multilayer coverage of the tube surface by bacteria was only achieved when fresh nutrient was pumped over deposited cells. This was attributed to cell growth. Although theoretical considerations of the deposition of small particles on to the walls of a tube suggest that the initial deposition rate should increase with flow rate, this was not the case with cells grown at dilution rates of 0.2 and 0.5 h-1. It is suggested that this can be explained by a polymer bridging mechanism of attachment.

Adhesiveness↗