Tritiated uridine uptake in the retinal ganglion cell layer of the cat during normal development and after visual cortex ablation.

The short-term metabolic response of immature retinal ganglion cells to destruction of their target cells in the dorsal lateral geniculate nucleus (dLGN) was assessed in newborn cats. Retrograde degeneration of virtually all dLGN cells was induced by ablation of the 13 contiguous areas of visual cortex on the day of birth. The metabolic response of retinal ganglion cells to this loss of target cells in dLGN was determined by exposing the ganglion cell layer to tritiated uridine, a precursor of RNA. Control measurements were made from unoperated littermates. Following sectioning and processing of the retinae from both groups of kittens for autoradiography, silver grain densities overlying the cellular profiles in the ganglion cell layer were calculated. These calculations revealed levels of uridine incorporation at Postnatal Day 4 in both groups of kittens significantly higher than at either Postnatal Day 2 or 7, but no significant differences between the two groups on any day examined. These results show that the level of RNA synthesis in retinal ganglion cells increases temporarily during the first postnatal week and that this synthesis is unaffected by the death of target cells in the dLGN. The temporary increase may be related to the establishment of synaptic connections on retinal ganglion cells by their afferent bipolar and amacrine neurons in the inner nuclear layer.

The use of closed suction drainage after lumpectomy and axillary node dissection for breast cancer. A prospective randomized trial.

Closed suction drainage has been used to prevent seroma formation after lumpectomy and axillary node dissection for breast cancer. To study the efficacy of closed suction drains, the authors conducted a prospective randomized study from 1987 to 1990 of 227 axillary dissections. One hundred eight were randomized to a drain group (DG) and 119 to a no drain group (NDG). Drains were removed on the first postoperative day just before patient discharge. Postoperatively, all palpable axillary collections were aspirated on each follow-up visit. The volume aspirated, the number of aspirations, the time to seroma resolution, and all complications were recorded. The mean number of aspirations in the DG was significantly lower than the NDG (2.2 +/- 2.2 versus 3.3 +/- 2.1; p less than or equal to 0.002). Mean volume aspirated in the DG (146.3 +/- 181.1 mL) was less than the NDG (266.1 +/- 247.6 mL; p less than or equal to 0.003), and the time to seroma resolution was decreased in the DG as compared with the NDG (11.5 +/- 10 days versus 18 +/- 10.1 days; p less than or equal to 0.0002). Closed suction drainage after lumpectomy and axillary node dissection is advantageous in decreasing the incidence and degree of seroma formation and need not delay early hospital discharge.