Biomedical subjects

Pamela J Middlemiss

Publications and source records attributed to Pamela J Middlemiss.

3 recordsLinked to original sources

PubMed2003

Enteric glia promote functional recovery of CTM reflex after dorsal root transection.

Transected dorsal root axons of adult rats can be induced to regenerate through the normally non-permissive environment of the dorsal root entry zone (DREZ) into the spinal cord by implanting enteric glia (EG) into the DREZ. We have now examined whether the regenerating central axons make functional connections by studying the return of function of a behavioral response, the cutaneous trunci muscle (CTM) reflex. Implantation of EG into the spinal cord DREZ led to functional recovery of the CTM reflex in 82%, 72% and 70% of animals 1, 2 and 3 months, respectively, after injury. In contrast, the CTM reflex did not recover in animals implanted with 3T3 or C6 glioma cells or with vehicle only.

3T3 Cells↗

PubMed2003

Enteric glia promote regeneration of transected dorsal root axons into spinal cord of adult rats.

After spinal cord injury axonal regeneration is poor, but may be enhanced by the implantation of olfactory ensheathing glia (OEG). Enteric glia (EG) share many properties of OEG. Transected dorsal root axons normally do not regenerate through the central nervous system myelin into the spinal cord. We tested whether EG, like OEG, could promote regeneration in this paradigm. Three weeks after EG implantation, numerous regenerating dorsal root axons reentered the spinal cord. Ingrowth of dorsal root axons was observed using 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate. Primary sensory afferents invaded laminae 1, 2, and 3, grew through laminae 4 and 5, and reached the dorsal gray commissure. No axonal ingrowth was observed in control animals, indicating that transplanted EG enabled regeneration of the injured dorsal root axons into the adult spinal cord. Thus, EG implantation may be beneficial in promoting axonal growth after central nervous system injury.

3T3 Cells↗

PubMed2002

A method for purifying enteric glia from rat myenteric plexus.

The enteric nervous system is a large and complex division of the peripheral nervous system. The glia associated with it share some characteristics with the olfactory-ensheathing glia, astrocytes and Schwann cells. To facilitate studies of rat enteric glia, we have developed a method for preparing them in large quantities with a high degree of homogeneity. The enteric glia were isolated from the small intestine of Wistar rats by enzymatic digestion with dispase. The cell isolate was added to a mitotically arrested layer of 3T3 cells. Subsequent separation of the enteric glia from the 3T3 cells was done enzymatically, with unavoidable loss of many enteric glia and potential contamination of enteric glia cultures with the 3T3 cells. Therefore, 3T3 cells were cultured in Nunc 0.2-microm tissue culture inserts that could be readily removed from the wells when no longer needed. There was no loss of the enteric glia. The cultures consisted entirely of GFAP-labeled cells, presumptive enteric glia. This method permits the culturing of large numbers of highly purified enteric glia without the use of expensive growth factors and complement-mediated cytolysis.

3T3 Cells↗