The acute effects of proton whole-body irradiation on the distribution and function of leukocyte populations in the spleen and blood were examined and compared to the effects of photons derived from a (60)Co gamma-ray source. Adult female C57BL/6 mice were exposed to a single dose (3 Gy at 0.4 Gy/min) of protons at spread-out Bragg peak (SOBP), protons at the distal entry (E) region, or gamma rays and killed humanely at six different times thereafter. Specific differences were noted in the results, thereby suggesting that the kinetics of the response may be variable. However, the lack of significant differences in most assays at most times suggests that the RBE for both entry and peak regions of the Bragg curve was essentially 1.0 under the conditions of this study. The greatest immunodepression was observed at 4 days postexposure. Flow cytometry and mitogenic stimulation analyses of the spleen and peripheral blood demonstrated that lymphocyte populations differ in radiosensitivity, with B (CD19(+)) cells being most sensitive, T (CD3(+)) cells being moderately sensitive, and natural killer (NK1.1(+)) cells being most resistant. B lymphocytes showed the most rapid recovery. Comparison of the T-lymphocyte subsets showed that CD4(+) T helper/inducer cells were more radiosensitive than the CD8(+) T cytotoxic/suppressor cells. These findings should have an impact on future studies designed to maximize protection of normal tissue during and after proton-radiation exposure.

No abstract

Recombinant viruses can produce cytokines in tumors mobilizing an immune response to tumor cells. In this study, the authors investigated gene expression, in vivo antitumor efficacy, and safety of attenuated recombinant vaccinia virus (rVV) carrying murine cytokine genes interleukin (IL)-2 (rVV-mIL-2), IL-12 (rVV-mIL-12), and both IL-2 and IL-12 (rVV-2-12) in an athymic nude mice model. Significant tumor inhibition (p < 0.05) was observed in a preestablished subcutaneously implanted C6 glioma model using rVVs at doses ranging from 10(2) to 10(7) plaque forming units (PFU). An antitumor effect did not depend on the dose of the rVV-mIL-2 and rVV-mIL-12 viruses. All constructed rVVs induced a high level of cytokine expression in vitro and in vivo. Most groups injected with high doses of recombinant viruses encoding cytokine genes (10(5) to 10(7) PFU) showed signs of cytokine toxicity, whereas in the low-dose treatment groups (10(2) to 10(3) PFU) toxicity was greatly reduced. The antitumor activity of rVV-mIL-12 was associated with increases in both the percentage and number of natural killer T cells in the spleen. Local detection of interferon-y and tumor necrosis factor-alpha was also correlated with tumor growth arrest induced by the treatment. High-dose VV control vector per se induced tumor inhibition by activating Mac-1+ cells in blood, but the antitumor effect was less pronounced compared with rVV-carrying cytokine genes (p < 0.05). These results suggest that attenuated recombinant strains of VV at low doses may potentially be efficient vectors for cancer immunotherapy.

Actinomyces spp. are considered rare pathogens in today's medicine, especially with thoracic vertebral involvement. Classic actinomycosis (50%) presents as an oral-cervicofacial ("lumpy jaw") infection. This report describes a case of spinal cord compression caused by Actinomyces israelii with the coisolation of Fusobacterium nucleatum. There are limited numbers of similar cases. CASE REPORTThe case described here involves a 43-year-old Filipino man who presented to a medical center emergency department with a chief complaint of acute lower back pain and urinary incontinence. He had been in his usual state of health until approximately 3 days prior to admission, when he first noticed a gradual onset of bilateral lower-extremity weakness, followed by difficulty with walking and, finally, the inability to arise from bed. In addition, the patient stated that he had been experiencing low-grade fevers and progressive weight loss over the past several months. His medical history was unremarkable and did not include any recent trauma. The patient had emigrated from the Philippines to Hawaii about 20 years earlier. However, he denied any history of exposure to tuberculosis or any recent travel back to the Philippines or Southeast Asia.In the emergency room, the patient appeared to be disoriented, although he was able to follow simple commands. His vital signs included a temperature of 97.8°F, blood pressure of 121/75 mm Hg, a heart rate of 116 beats/min, and mild tachypnea, with an O 2 saturation of 99% on room air. On physical examination, he was noted to have poor dentition and evidence of multiple previous dental extractions. A neurological examination revealed significant bilateral lower-extremity weakness (two of five) with brisk deep-tendon reflexes, positive ankle clonus, and a positive Babinski sign, as well as diminished rectal tone. The remainder of the physical examination was unremarkable. Laboratory blood findings were significant for leukocytosis (22.0 ϫ 10 9 /liter) with 87% segmented neutrophils, an elevated platelet count of 722 ϫ 10 6 /liter, and an erythrocyte sedimentation rate of 84 mm/h. A screen for human immunodeficiency virus type 1 and 2 antibodies was negative. The remaining laboratory findings were noncontributory.A chest X ray showed a left-lower-lobe infiltrate with minimal pleural effusion.Because of the possibility of spinal cord compression and injury, the patient was admitted to the medical intensive care unit for further workup and management. This included magnetic resonance imaging of the spine, which showed an abnormal signal intensity involving the thoracic vertebrae from T5 through T8 and an abnormal soft tissue mass enhancement consistent with an apparent abscess that involved the left posterior chest wall and ribs and that extended to the thoracic vertebral column and into the epidural space, with apparent spinal cord compression. A computed tomography scan of the chest revealed similar abnormal findings involving the left posterior chest wall and ribs as well as a collapsed lef...

Our previous studies have shown that vaccinia virus ( VV ) expressing p53, interleukin -2 ( IL -2 ) , and interleukin -12 ( IL -12 ) results in an effective inhibition of subcutaneous glioma growth in mice. We propose that combination therapy of tumors with virusmediated p53 and cytokine genes offers the prospect of synergistic antitumor response. In this work, the antitumor efficacy of VVmediated combination of p53, IL -2, and IL -12 genes was evaluated in a nude mouse model. To minimize cytokine -associated toxicity, a virus dose as low as 10 plaque -forming units of VV expressing IL -2 and IL -12 per animal was used alone and together with 2Â10 7 plaque -forming units of VV expressing p53. Intratumoral treatment of established C6 glioma with recombinant viruses rVVp53, rVV -mIL2, rVV -mIL12, and rVV -2 -12 induced the prolonged expression of p53, IL -2, IL -12, and both cytokines simultaneously. The combination of rVV -p53 / rVV -mIL12 or rVV -p53 / rVV -2 -12 resulted in significant tumor inhibition compared to single modality treatment ( P < .05 ) . rVV -p53 / rVV -2 -12 therapy was associated with significant elevation of natural killer, Mac -1 + , and NKT cells in blood and interferon -and tumor necrosis factor -expression in tumors. The difference in the inhibition of tumor growth between the rVV -p53 / rVV -mIL2 combination and rVV -p53 was statistically insignificant. These data demonstrate that gene therapy based on VV -mediated combination of p53, IL -2, and IL -12 treatment may be a promising adjunctive strategy for glioma treatment.

Recent reports have shown that tumor necrosis factor-alpha (TNF-alpha) can augment the effects of radiation against certain tumor types. However, the high concentrations of intravenous infusion of TNF-alpha needed to cause tumor regression can induce many systemic side effects. The aims of this study were to determine if TNF-alpha encapsulated in sterically stabilized (Stealth, ALZA Corporation, Mountain View, CA), PEGylated liposomes (SL) augments the antitumor effects of radiation and to compare its efficacy and possible toxicity with free TNF-alpha in the LS174T human colon tumor xenograft model. Nude mice were injected subcutaneously (s.c.) with LS174T cells and treated intravenously (i.v.) with Stealth-liposomal TNF-alpha (SL-TNF-alpha) with and without radiation or TNF-alpha with or without radiation when tumor size was approximately 200 mm(3). In phase 1, a significant decrease (p = 0.047) in tumor growth was observed with radiation at day 21 but not with SL-TNF-alpha or free TNF-alpha alone. By the end of phase 1 (day 27) with continued treatments, the SL-TNF-alpha plus radiation group had significantly smaller tumors (p = 0.044) than those in the free TNF-alpha plus radiation group. In phase 2, where a similar tumor growth reduction pattern was observed, the addition of TNF-alpha to radiation, either as free protein or within SL, increased lymphocyte activation and natural killer (NK) cell numbers in both blood and spleen. The effect was generally more pronounced with SL-TNF-alpha. Systemic toxicity, based on hematologic analyses and body weight, was absent or minimal. Collectively, the data show that pretreatment with SL-TNF-alpha can enhance more effectively, and possibly more safely, the effects of radiation against human colon tumor xenografts than can free TNF-alpha and that the increased antitumor action may involve upregulation of lymphocytes.

No abstract

The major goal of this study was to evaluate the effects of tumor necrosis factor-α (TNF-α), delivered as pGL1-TNF-α, on hematological variables, as well as C6 tumor growth in athymic mice treated with and without radiation. pGL1-TNF-α was administered intratumorally at low to high doses (15, 150 and 450 µg) in all three phases of this study. In phase A, pGL1-TNF-α expression within tumors was dose dependent and transient, with highest levels seen at 18 h after injection, whereas no TNF-α protein was detected in plasma. Low erythrocyte counts, hemoglobin, and hematocrit were associated with tumor presence, but the reduction in these variables was most striking in the group receiving 450 µg of pGL1-TNF-α, the group that also exhibited thrombocytopenia at 72 h. In phase B, treatment with pGL1-TNF-α at 15 or 150 µg resulted in the greatest degree of splenomegaly, increased spontaneous blastogenesis by splenocytes, and high leukocyte and lymphocyte numbers in the spleen. In these same two groups, flow cytometry analyses of spleen cells showed that high levels of natural killer (panNK+) cells, B (CD19+) lymphocytes, and cells expressing the CD71 and CD25 activation markers were present (p < 0.05). An enhancing effect was also noted in some of the measurements with parental plasmid p WS4 and tumor presence. In phase C, the slowest tumor progression was observed in the groups receiving 15 and 150 µg pGL1-TNF-α together with radiation; tumor volumes were 51 and 43% smaller, respectively, than for PBS-injected controls by the end of the study. Collectively, these results show that localized treatment with pGL1-TNF-α is hematologically nontoxic at low doses and support the premise that activation of lymphocytes may contribute to the antitumor effects of radiation against a highly aggressive brain tumor.