Philip Furmanski

Influence of lactoferrin feeding and injection against systemic staphylococcal infections in mice

Human and bovine lactoferrins (Lfs) and bovine lactoferrin hydrolysate (LH) were assessed in vitro and in vivo for their antibacterial effects on Staphylococcus aureus. Lactoferrins showed weak in vitro antibacterial activity while Fe‐saturated Lfs and LH showed no activity. Lactoferrin‐treated mice (1 mg, i.v.) when injected i.v. with 106 staphylococci, showed 30–50% reduction in kidney infections, and viable bacterial counts in the kidneys decreased 5–12‐fold. The inhibitory effect was dose‐dependent up to 1 mg Lf. Lactoferrins were effective when given 1 day prior to the bacterial challenge, after which there was no significant effect even at doses up to 5 mg. Apo‐ and Fe‐saturated forms of human and bovine Lfs were all equally effective, while LH was not protective. Human and bovine Lfs with different degrees of iron saturation (9–97%) were found to be equipotent. Feeding mice with 2% bLf in drinking water also reduced the kidney infections by 40–60%, and viable bacterial counts, 5–12‐fold. The results suggest a potential for the use of Lfs as natural antibacterial proteins for preventing bacterial infections.

The etiology of breast cancer.

A dominant focus of the research programs at our own and other laboratories remains the identification and characterization of the populations at high risk to breast cancer. The goal: the early detection of the disease and, ultimately, its biological control.

Infection of macrophages with friend virus: Relationship to the spontaneous regression of viral erythroleukemia

Abstract Resident peritoneal macrophages from normal mice were refractory to infection with the RFV or conventional strains of Friend virus (FV). Stimulation of DNA synthesis in the macrophage population by induction of an exudate in vivo or treatment in vitro with macrophage colony-stimulating factor resulted in productive infection following exposure to virus. Similarly, normal resident macrophages did not become infected in vivo following transfer to leukemic mice, while exudate macrophages did become infected. Bone marrow macrophage stem cells were stimulated to replicate and mature in clonal agar cultures in the presence of colony-stimulating factor. These replicating stem cells could be infected with RFV, as shown by virus production in the resultant progeny macrophages. Transfer of normal resident peritoneal macrophages to leukemic progressor mice caused regression of the disease. In contrast, transfer of normal bone marrow cells was ineffective in causing leukemia regression. During erythroleukemogenesis induced by RFV, macrophage precursor cells in all of the mice became infected with virus. In mice with a progressive and lethal leukemia, mature end-stage macrophages were produced which were also infected with virus. In mice in which the leukemia would later spontaneously regress, the infected stem cells were eliminated and the marrow became repopulated with uninfected cells. The resultant progeny macrophages which appeared in the peritoneal cavity were uninfected and thus capable of participating in or causing leukemia regression.

High-level conjugation of chelating agents onto immunoglobulins: use of an intermediary poly(l-lysine)-diethylenetriaminepentaacetic acid carrier

Diethylenetriaminepentaacetic acid (DTPA), a strong chelating agent, was covalently linked to murine monoclonal anti-HLA IgG1 antibody (H-1) with the use of poly(L-lysine) (Mr 14,000) as a multivalent, intermediary carrier, via thiol-disulfide exchange reaction. The conjugates contained up to 42.5 mol DTPA per mol antibody, and retained over 90% of their antibody activity in vitro. The conjugates incorporated gadolinium (Gd) through an exchange reaction with Gd-EDTA, used to prevent colloid formation and nonspecific binding of the free metal. The IgG-poly(L-lysine)-DTPA-Gd had a greater effect per mol on proton relaxation rates than DTPA-Gd itself. Use of poly(L-lysine) as an intermediary carrier for attachment of chelating agents to IgG thus offers great potential for achieving high-specific-activity conjugates, particularly for use as biologically specific contrast agents in nuclear magnetic resonance imaging.

1H-NMR relaxation times and water compartmentalization in experimental tumor models

The present studies were conducted with RIF-1, M5076 and Panc02 subcutaneous tumor models to assess the relationship between tissue-free water compartmentalization and observed tissue T1 and T2 changes at 10 MHz. Observed T1 was shown to correlate directly with total extracellular water and interstitial water volumes. T1 and T2 were also inversely related to intracellular water volumes. T1 and T2 decreases after dexamethasone treatment were, however, most closely correlated with changes in tumor extracellular water and not changes in cell or total water volumes. Studies to assess Gd-DTPA-dimeg dose dependent T1 and T2 modification in model serum protein solutions indicated that although the Gd concentration that reduced T2 by 50% was about 2.5 fold greater than that required to reduce T1 equally, the of the concentration dependent T1 and T2 modifications were similar. In studies with tumor models, the injected dose of Gd-DTPA-dimeg that reduced T1 by 50% was inversely correlated with tumor extracellular water volumes. The slopes for dose dependent T1 modification in all tumors were similar and similar to that observed for model protein solutions. Gd-DTPA-dimeg had a different effect on observed T2 values for the 3 tumor models. Exponential slopes were about twice that observed for T2 modification of serum protein solutions, and Gd-DTPA-dimeg doses that reduced observed tumor T2 ranged from 9 to 50 times that necessary to similarly reduce T1. The results from these studies indicate that the observed T1, for these tumors, was dominated by relaxation of water protons in interstitial water but that the observed T2 was most strongly influenced by proton relaxation in water compartments that were unavailable to the Gd labeled probe.

Effect of conjoint administration of tamoxifen and high-dose radiation on the development of mammary carcinoma

PURPOSE Tamoxifen is currently advocated for post-menopausal breast cancer patients receiving definitive irradiation after limited surgery. The purpose of this study was to assess in an experimental model for breast cancer whether the efficacy of irradiation is altered by conjoint administration of tamoxifen. To this end, rats with small tumors induced by 1-methyl-1-nitrosourea (MNU) were treated with tamoxifen, radiation, or a combination of the two modalities. METHODS AND MATERIALS Female Sprague Dawley rats were injected i.p. with 50 mg MNU/kg body weight at 50 days of age. At 64 days post carcinogen, the majority of the rats had at least one palpable mammary tumor. At that time radiation with or without tamoxifen treatment was initiated and given 5 days per week for 5 weeks. Radiation dose was 4500 cGy delivered as 25, 180 cGy fractions. Tamoxifen, 500 mg/kg body weight, was administered subcutaneously each day during the irradiation interval. The study was terminated 28 weeks after carcinogen treatment. RESULTS High dose radiation alone induced a reduction in the size of existing tumors, but resulted in a significant increase in the number of tumors that were detected. Treatment with tamoxifen alone also caused a reduction in tumor volume, but had no effect on final incidence or number of mammary tumors. Combined modality treatment resulted in a significant reduction in the volume of existing tumors and suppressed the enhanced occurrence of additional tumors observed when only radiation alone was administered. CONCLUSION The findings of this study indicate that in the context of fractionated, high dose radiation treatment of established mammary cancers, tamoxifen may reduce the likelihood of subsequent tumor development and by so doing prove a helpful simultaneous conjoint adjuvant treatment to post-operative irradiation.

The measurement of extracellular water volumes in tissues by gadolinium modification of 1H-NMR spin lattice (T1) relaxation

The present studies were conducted in RIF-1, M5076 and Panc02 murine tumor models to compare extracellular water measurements made by 51Cr-EDTA dilution techniques and a new method which exploits the concentration dependent modification of 1H-NMR proton relaxation by Gadolinium-DTPA-dimethyl glucamine (Gd-DTPA-dimeg) in plasma and tissues. The time dependent changes in T1 modification in tissue and plasma were determined at various intervals after i.v. injection of 0.1 ml of 100 mM Gd-DTPA-dimeg and Gd concentrations determined from standard curves of Gd concentration dependent T1 modification of mouse plasma. Comparison of tissue and plasma Gd concentrations permitted the calculation of Gd-DTPA-dimeg distribution volumes. In unperturbed RIF-1, M5076 and Panc02 tumors, Gd-DTPA-dimeg distribution volumes determined by the T1 modification technique were similar to extracellular water spaces determined by 51Cr-EDTA dilution assays. In mouse liver, the 51Cr-EDTA assay resulted in artifactually high extracellular water space estimates due to internalization of the probe; Gd-DTPA-dimeg distribution volumes determined in liver with both the 153Gd-DTPA-dimeg and by the T1 modification method were approximately 150 ul/gram. The Gd-DTPA-dimeg T1 modification method also provided good approximations of changes in extracellular water volumes in RIF-1 tumors after dexamethasone and cyclophosphamide treatments. These results indicate that Gd-DTPA-dimeg modification of proton relaxation may be extremely useful for monitoring changes in tumor water dynamics during cancer therapy.

Synergistic enhancement by interleukin-1 α of cisplatin-mediated antitumor activity in RIF-1 tumor-bearing C3H/HeJ mice

Administration of interleukin-1 α (IL-1 α) plus certain cytotoxic drugs causes substantially greater clonogenic tumor-cell kill and tumor-regrowth delay than does treatment with either agent alone. IL-1 α itself has little effect on tumor growth despite its ability to induce acute hemorrhagic necrosis, restrict tumor blood flow, and cause microvascular injury in a variety of murine model systems. To investigate further IL-1 αs ability to enhance the antitumor activity of cytotoxic drugs, we initiated studies to examine the effect of IL-1 α on cisplatin (cDDP)-mediated cytotoxicity using the RIF-1 tumor system. The antitumor activity of IL-1 α and cDDP was quantitated through standard clonogenic tumor-cell survival assays, a tumor hemorrhagic necrosis assay and tumor-regrowth delay studies, with the interaction between IL-1 α and cDDP being analyzed through median dose-effect. In vitro, IL-1 α had no enhancing effect on the cDDP-mediated tumorcell kill. For examination of the in vivo efficacy of this regimen. RIF-1 tumor-bearing C3H/HeJ mice (14 days postimplantation) were treated concurrently with single i.p. injections of IL-1 α and/or cDDP at various doses. The increased clonogenic tumor-cell kill obtained with IL-1 α /cDDP was dose-dependent, with significant enhancement by IL-1 α being observed (P<0.001), even at the lowest doses tested (2 mg/kg and 6 μg/kg for cDDP and IL-1 α, respectively), but it did not correlate with an increase in tumor hemorrhage. Using median dose-effect analysis, this interaction was determined to be strongly synergistic. When treated animals were monitored for long-term antitumor effects, combinations with IL-1 α significantly increased the tumor-regrowth delay and decreased the fractional tumor volume (P<0.001). These results demonstrate that IL-1 α synergistically enhances cDDP mediated in vivo antitumor activity and suggest that the combination of IL-1 α and cDDP may have potential therapeutic application in the design of effective treatment modalities for cancer.

Revealing the Mechanism of Tissue Damage Due to Tobacco Use : Finally, a Smoking Gun?

This commentary highlights the article by Li et al that presents a compelling case for a mechanism by which tobacco smoke extract (TSE) induces damage to the extracellular matrix, a key element in the pathogenesis of tobacco-related disease.

Radioimmunolocalization of breast cancer using BrE-3 monoclonal antibody.

Radioimmunolocalization for detection or therapy of breast cancer has undergone only limited investigation. Successful targeting of breast tumors with radiolabeled antibodies has awaited the identification of the optimal antigen targets, the appropriate antibodies, as well as the linking chemistry necessary to produce stable radioimmunoconjugates. Radioimmunodetection trials in breast cancer have employed both the intravenous and interstitial administration routes. Sensitivity of intravenously administered immunoconjugates for metastatic disease has ranged from 50-78% in small series of patients 1-3. The antibodies used in these trials were directed against various breast cancer associated antigens including human milk fat globule membrane (HMFG) or breast epithelial mucin and CEA. Excellent sensitivity for primary breast tumors using an antibody directed against TAG-72 has been reported3, but in the same patients,