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Biomedical subjects

T D Allen

Publications and source records attributed to T D Allen.

At least 199 records · Page 11Linked to original sources
PubMed1975

The transpubic approach for strictures of the membranous urethra.

Strictures of the membranous urethra following pelvic fractures pose a challenge in management because of their relatively inaccessible position above the urogenital diaphragm and behind the pubic symphysis. The corrective procedures the pass up from the perineum through the urogenital diaphragm to reach the stricture have the real or theoretical disadvantage of defunctionalizing the external urethral sphincter and leaving continence dependent solely upon the competency of the bladder neck. On the other hand, transpubic surgery allows a direct attack upon the stricture without violating the sphincter. Our experience with 4 such cases has convinced us of the superiority of this approach.

Adult↗
PubMed1975

The fine structure and cell kinetics of mouse epidermis after wounding.

A variable amount of cornified tissue removed from mouse dorsal epidermis results in stimulation of the entire basal layer. Stimulation does not appear to be dependent on damage to an indiviaual epidermal proliferative unit (EPU). The immediate reaction to wounding is a rapid movement of cells from the basal layer to the differentiating compartment resulting in depopulation of the basal layer, which is followed by a burst in DNA-synthetic activity. The result of the increased transit of cells through the epidermis is that various aspects of keratinization can appear abnormal. The Langerhans cells show several changes, often appearing suprabasal and becoming smaller, rounded cells with a less-clear cytoplasm and fewer granules. The initial migratory reaction results in a largely normal epidermis on the third day. This reaction is followed by a transient hyperplasia which reaches its peak on the sixth to seventh day and gradually returns to normal by the fourteenth to fifteenth day. The hyperplasia is characterized by a loss of the ordered stacking of cornified cells which become shorter and thicker than normal. There is a return to the stacked state beginning on the tenth day. The Langerhans frequency is apparently at its lowest on days 6-7 when the proliferation levels are at their maximum. An inverse relationship appears to exist between relative Langerhans cell frequency and cell proliferation rate. The data suggest that the frequency of Langerhans granules also changes during the course of the hyperplasia, peak levels being observed just before the decline in proliferative activity.

Animals↗