Identification of human pre-T/NK cell-associated genes.

We have used a combination of subtractive cloning and differential screening techniques to identify genes preferentially expressed in early stages of human T/NK cell development compared with mature T and NK cells. A fetal liver-derived cytoplasmic (c) CD3+ membrane (m) CD3- clone, FL508, which expresses markers characteristic of pre-T and pre-NK cells served as a cell source for our cloning experiments. A cDNA library enriched for genes expressed in FL508 was constructed by removal of cDNA that hybridized to mRNA from a B cell line, JY. One-tenth of the resulting library of 5000 clones was screened by differential hybridization with cDNA probes from JY and a mature CD4+ T cell clone, B21. The relative expression levels of six selected clones were analyzed in 17 different cell/tissue types by semiquantitative polymerase chain reaction. Four of these clones are expressed at higher levels in thymocytes than in mature T or NK cells, and three clones are expressed at higher levels in fetal liver cells than in either mature T or NK cells. Partial and complete DNA sequence information suggests that these six cDNA correspond to previously unidentified genes. Genes identified in this study may be useful not only as markers for early stages of T/NK cell ontogeny, but also as tools for understanding novel developmental events.

Effect of patient positioning on urethral mobility: implications for radical pelvic surgery.

Patient positioning is of critical importance in the successful performance of several radical pelvic operations. Adequate exposure of the prostatic apex is vital in ligating the dorsal vein complex and performing vesicourethral anastomosis. To test the effect of different patient positions on urethral mobility, we conducted a prospective controlled study measuring the relative cephalad displacement of the prostatic apex in 3 positions, that is the supine, frog-leg and dorsal lithotomy positions. A combination of radiographic and cystoscopic techniques was used to mark the position of the prostatic apex. Each patient served as his own control. Of the 24 patients studied for a variety of urological complaints 19 (79%) had an increased cephalad displacement of the prostatic apex while in the frog-leg position compared with the dorsal lithotomy position. The mean gain was 0.5 cm. (p greater than 0.5). A total of 16 patients showed improvement while in the frog-leg position over the supine position with a mean advantage of 0.39 cm. (p greater than 0.05). Patient age, pelvic depth, pelvic circumference and prostatic urethral length had no predictive value in selecting an optimal position.

Solitary metastasis of renal cell carcinoma to urethra.

A case report of a solitary metastasis to the urethra from previously resected renal cell carcinoma is reported. The patient presented with total gross painless hematuria. We believe this is the first such case to be reported.