Antitumor activity of murine neutrophils demonstrated by cytometric analysis.

The cytostatic and cytolytic activities of activated polymorphonuclear neutrophils (PMNs) against YAC-1 lymphoma target cells were examined using multiparameter flow cytometric analysis. PMNs were resolved from tumor cells by 90 degrees light scatter. The number of surviving tumor cells was determined by adding a known concentration of fluorescent latex particles to the fixed cell suspension immediately prior to analysis and counting the particles simultaneously with the cells. Cell cycle progression of the YAC-1 target was studied by dual parameter analysis of DNA content and bromodeoxyuridine incorporation into tumor cell DNA either prior to or following addition of PMNs. The results indicate that activated PMNs effectively kill tumor cells within the first 24 h of coculture. However, between 24 and 48 h, tumor cells which escape destruction resume growth and eventually reach a growth rate greater than control cells.

Selective immunosuppression in mice of natural killer cell activity by ochratoxin A.

Ochratoxin A, a naturally occurring mycotoxin, has recently been shown to cause renal and hepatic carcinomas in mice. In the present studies, the effects of ochratoxin A on immune mechanisms associated with tumor resistance were examined in mice using dose levels similar to those that cause neoplasia. Ochratoxin A was shown to specifically inhibit natural killer (NK) cell activity and increase the growth of transplantable tumor cells without altering T-cell- or macrophage-mediated antitumor activity. In contrast, ochratoxin B, a much less toxic ochratoxin, did not influence immune function. Polyinosinic:polycytidylic induced interferon was markedly reduced in mice following exposure to ochratoxin A although total serum protein levels were slightly increased. Injection of polyinosinic:polycytidylic enhanced NK activity in the presence of ochratoxin A, although the level of enhancement was slightly lower than that produced by the agent in the absence of ochratoxin A. Thus, ochratoxin appears to suppress NK cell activity by inhibiting production of basal interferon. Additionally, these findings suggest a possible role for altered NK cell function in the development of mycotoxin-induced carcinogenesis.

Primary Hodgkin's disease of the sigmoid colon: a case report and review of the literature.

We report the case of an 81-year-old man who underwent a segmental resection of the sigmoid colon for severe diverticular disease. Histopathologic diagnosis revealed extranodal Hodgkin's disease, and the diagnosis was confirmed by immunohistochemistry. The incidence of extranodal Hodgkin's disease is rare and represents an infrequent occurrence as a gastrointestinal neoplasm and primary gastrointestinal lymphoma. A review of the literature for gastrointestinal lymphomas with emphasis on the occurrence of Hodgkin's disease, the diagnostic features, and the site of gastrointestinal tract involvement is reported.

Complications following butane inhalation and flash fire.

Solvent inhalation is a well-documented form of drug abuse that can cause euphoria and hallucinations. Sudden death involving a volatile substance is most commonly caused by cardiac arrythmias, asphyxia, direct drug effects, and trauma. The victim in this paper suffered superficial partial thickness (12% total body surface area) burns from a flash fire that occurred when lighting a match after inhaling butane in an enclosed vehicle. The victim was admitted to the hospital for 2 days of observation but did not develop any respiratory symptoms under 2 days following her release. The victim died during her readmission, 9 days after the flash fire. Postmortem examination showed extensive epithelial injury from the upper airway and trachea to the terminal bronchioles, most likely due in part to both the initial inhalation injury and the resulting adult respiratory distress syndrome (ARDS) and staphylococcal infection. Many victims with superficial burn injuries may not seek medical attention owing to either embarrassment or fear of legal prosecution. Even those who do seek medical assistance may not reveal solvent abuse as the cause of their injuries. It is possible that delayed death may occur at home following volatile substance abuse but may remain unrecognized even with a thorough scene investigation.

Selective inhibition of polymorphonuclear neutrophil activity by 2,3,7,8-tetrachlorodibenzo-p-dioxin.

Although the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), via its interaction with the Ah receptor, is an extremely potent carcinogen and immunosuppressive agent in experimental animals, its possible actions on polymorphonuclear (PMN) function have not been determined. In addition to their importance against infectious organisms, PMNs have been implicated in antitumor resistance. The present studies examined the effects of in vivo exposure to TCDD on PMN function in B6C3F1 (TCDD sensitive, presence of high affinity Ah receptor) and DBA/2N (TCDD resistant at low doses, defective Ah receptor) mice. Animals received a single oral exposure of 5 or 10 micrograms/kg of TCDD and PMNs were obtained 5 days later from the peritoneal cavity following elicitation with sodium caseinate. TCDD reduced the cytolytic and cytostatic activity of PMA-activated PMNs in B6C3F1, but not in DBA/2N mice, suggesting that this response segregates with the Ah locus. Furthermore, TCDD was found to bind specifically to PMNs from Ah-responsive mice. Neither the production of superoxide and hydrogen peroxide nor degranulation, the latter measured by beta-glucuronidase release, was impaired. Supernatants recovered from PMN cell cultures of TCDD-sensitive mice, but not from resistant DBA/2N mice, showed reduced killing capacity for actinomycin D-treated L929 tumor cells, while their ability to bind to tumor cells was not altered. These data suggest that TCDD interferes with PMN-mediated tumor cell killing by altering the production or secretion of a cytolytic factor. Examination of bone marrow stem cells revealed that granulocytic but not monocytic colonies were reduced after TCDD exposure in vivo and in vitro. Although mature PMNs had detectable levels of Ah receptor, exposure in vitro of these cells to TCDD had no effect on antitumor activity. Thus, it is possible that TCDD may affect PMNs at the level of hematopoiesis, via a direct interaction with granulocyte precursor cells, or modulate PMNs at different stages of maturation.

Comparative effects on the immune system of methotrexate and trimetrexate.

Methotrexate (MTX) is an antimetabolite commonly used in the treatment of neoplastic disease, while trimetrexate (TMQ) is an investigational antifolate which is currently advocated as a potential alternative to MTX. The cytotoxic properties of antifolates to rapidly proliferating cells suggests that the immune system would be a significant and undesirable target for these drugs. We examined the comparative effects of these two chemotherapeutic agents on the murine immune system using in vivo and in vitro methods. Both drugs were potent suppressors of T-dependent antibody formation in vitro as well as in vivo. While TMQ appeared to be more immunosuppressive than MTX following in vitro addition of the drugs, the converse appeared to be true when dosing was performed in vivo. The drug induced suppression of T-dependent antibody formation was dose dependent for both antifolates. Lymphoproliferative studies demonstrated marked suppressive effects on LPS and PHA induced 3H-uridine and 3H-deoxyuridine incorporation following addition of both drugs in vitro suggesting effects on both RNA and thymidylate biosynthesis. Timed addition studies demonstrated a particularly susceptible time period (hours 24-48 after addition of the mitogen LPS) in stimulated lymphocytes with respect to inhibition of 3H-uridine incorporation. Following in vivo administration of either antifolate, natural killer cell activity was significantly decreased with no substantial differences between the two drugs.(ABSTRACT TRUNCATED AT 250 WORDS)