Evaluation of the anatomy of the common peroneal nerve. Defining nerve-at-risk in arthroscopically assisted lateral meniscus repair.

A two-part study was undertaken to clarify the anatomy of the common peroneal nerve at the level of the lateral joint line and risk factors associated with arthroscopically assisted inside-out lateral meniscus repair. In part I, 70 legs in 35 preserved cadavera were dissected to evaluate the relevant anatomy of the common peroneal nerve; 7 (10%) manifested division of the common peroneal nerve into deep and superficial branches proximal to the knee joint. A cutaneous branch not previously described in the literature emanated from the common peroneal trunk in 21 of the legs (30%). In part II, arthroscopically assisted inside-out lateral meniscus repair was performed on 10 fresh-frozen cadaveric knees. Divergence between suture arms increased as suture position was sequentially posterior. Capture of a nerve branch occurred in 2 knees (20%) when posterior retraction was not used. Nerve involvement was eliminated when a retractor was employed. There was significant anatomic variability in the course and branching pattern of the common peroneal nerve at the level of the lateral joint line. During arthroscopically assisted inside-out lateral meniscus repair, risk of injuring the peroneal nerve was related to suture position because of the proximity of anatomic structures and the tendency for suture divergence with soft tissue tethering.

Selective accumulation of T cells according to T-cell receptor V beta gene usage in skin cancer.

To investigate whether specific T-cell populations are overrepresented in tumor-infiltrating lymphocytes (TIL) in skin cancer, we determined the T-cell receptor (TCR) diversity in biopsy specimens of basal cell carcinoma and squamous cell carcinoma. Immunostaining of tissue sections indicated that the majority of T cells expressed alpha beta TCRs. To assess diversity of the TCR beta chain, RNA was isolated directly from the tumor specimens and peripheral blood mononuclear cells (PBMC) from the same patient, cDNA was synthesized, and variable (V) beta chain gene usage was determined by the polymerase chain reaction (PCR). In each basal cell (n = 11) and squamous cell (n = 7) carcinoma studied, several V beta families were overrepresented in TIL versus PBMC, in that they accounted for greater than 5% of the repertoire in TIL and were at least 2% higher in TIL than in PBMC. The predominant V beta gene segments overrepresented in TIL generally differed from individual to individual. Simultaneous comparison of the V beta repertoire of TIL to that of uninvolved skin and PBMC from the same individual revealed preferential expression of V beta families within the TIL in three of five basal cell and four of four squamous cell carcinomas. Again, the predominant V beta s differed from individual to individual. Comparison of the TCR repertoire in uninvolved skin versus PBMC did indicate that some V beta families were overexpressed in the resident T-cell compartment in skin, although the overrepresented families were not constant from individual to individual. These data indicate the selective concentration of T cells bearing specific alpha beta TCRs in the local immune response to basal cell and squamous cell carcinomas.

Cloning and sequencing of a trophoblast-endothelial-activated lymphocyte surface protein: cDNA sequence and genomic structure.

We have previously described the distribution of a surface glycoprotein recognized by monoclonal antibody B721. We now report the molecular characterization of this molecule at the protein, cDNA, and genomic level. A 75-kDa glycoprotein can be immunoprecipitated from B721+ tissues. We have isolated a near full-length cDNA containing the complete coding region and a full-length genomic clone. We present evidence that this protein has similarity to several classes of nuclear transcription factors, particularly the myc family of proteins. The 721P protein was found to have a leucine zipper-like structure, a possible basic region immediately upstream from the leucine zipper, and a protein kinase A phosphorylation site. 721P protein is encoded by a gene distinct from any deposited in existing data bases, and displays several features associated with proteins involved in signal transduction and gene regulation.