Raymond B. Hester

Chondrocyte Viability in Refrigerated Osteochondral Allografts Used for Transplantation Within the Knee

Purpose To evaluate cell viability and matrix characteristics of refrigerated osteochondral allografts implanted up to 44 days after harvest. Methods Sixteen refrigerated allografts underwent histologic and ultrastructural examination and fluorescence excitation analysis prior to implantation. The average size of the graft implanted was 6.2 cm2 (± 3.4 cm2). Refrigerated allografts averaged 30 days (range, 17 to 44 days) from donor expiration to implantation. Nine specimens underwent cell viability testing. The percent viability of refrigerated allografts prior to implantation averaged 67%. Results No significant correlations were noted between histologic score, electron microscopy score, matrix staining percent (MSP) score, and viability. When time to implantation was assessed, an inverse correlation was noted with MSP score (r= .539) (P< 0.05), indicating less matrix staining in grafts refrigerated longer after harvest. Conclusion The current data indicate that refrigerated osteochondral allografts can be maintained for up to 44 days with average chondrocyte viability of 67%.

Human squamous cell carcinoma lines express oncofetal 44‐kd polypeptide defined by monoclonal antibody to mouse fetus

Most primary human carcinomas uniformly express an oncofetal epitope which has not been demonstrated previously in established human carcinoma cell lines. We successfully derived several low‐passage cell lines of human squamous cell carcinoma (SCC) from head and neck tumors using an in vitro adaptation procedure, characterized these lines, and examined them for expression of a 44‐kilodalton (kD) polypeptide (PP) oncofetal antigen (OFA) at the cell surface. Newly established and in vitro‐passaged SCC cells retained characteristic microvilli, numerous desmosomes and tonofilaments, abundant rough endoplasmic reticulum, osmophilic keratohyaline granules, and other features of the primary SCC cells. These new cell lines and two long‐term, established SCC lines (FaDu and Detroit 562) displayed OFA at the cell surface, as determined by flow cytometry using monoclonal antibody (MoAb) 115. While the FaDu and Detroit 562 lines exhibited aneuploidy during flow cytometric analysis, the new, low‐passage SCC lines that we developed remained diploid as were the primary SCC cells from which they were derived. We propose that the expression of a 44‐kD OFA is a common feature of human SCC. This marker may prove useful in the detection and treatment of these tumors.

Inhibition of lymphocyte blastogenesis caused by suppression of interleukin-2 receptor sites after thermal injury.

Burn patients often exhibit prolonged cell-mediated immune suppression. Of the mechanisms proposed to account for this, one invokes an inability on the part of T lymphocytes to undergo blastogenesis, clonal expansion, and differentiation--a process partially mediated by interleukin-2. Triplicate samples of 10% dilutions of burn serum from nine burn patients (three with greater than 60% burn) were analyzed for their ability to suppress mitogen-induced lymphocyte blastogenesis. A separate aliquot of stimulated cultured lymphocytes was tagged with a monoclonal antibody to interleukin-2 receptors. The serum of patients with greater than 60% burn was significantly more suppressive (as measured by depressed tritiated thymidine incorporation by cultured lymphocytes) than that taken from patients with smaller burns. In addition, serum from those with larger burns caused a marked reduction in the interleukin-2 receptor-labeling index, suggesting that it possesses factor(s) that directly or indirectly block T lymphocyte interleukin-2 receptor expression.

ISOLATION AND EXAMINATION OF PUTATIVE TYPE II PNEUMOCYTE PRECURSORS

Type II alveolar epithelial cells exhibit a membrane antigen, designated p146, that is not present on other adult lung cells. This monoclonal antibody-identified marker enables these cells to be identified in sections of rat lung and to be isolated from other lung cells by a fluorescence-activated cell sorter (FACS IV). We now have adapted this latter technology to fetal rat lung and in so doing have obtained data supporting the contention that the fetal cells expressing p146 are precursors of Type II cells.Lungs from fetal rats 15 to 19 days of gestation were isolated and the cells dispersed with trypsin. The cells were incubated with the monoclonal antibody JBR-1, and then with fluorescein-tagged goat anti-mouse immunoglobulin. Analysis by FACS IV revealed a population of p146 positive fluorescent cells at all gestational periods examined. The fluorescent cells from 19 day fetal lungs were sorted and examined. Approximately 30% exhibited lamellar bodies by electron microscopy. Essentially all contained surfactant apoprotein (SAP) as indicated by immunological analysis. The p146 negative cells did not react with antibody to SAPBecause SAP is synthesized at 19 days gestation only in p146 positive cells and essentially all positive cells synthesize SAP we conclude the fetal cells expressing p146 are precursors of Type II pneumocytes.