ABSTRACT
BACKGROUND: Hyperbaric oxygen (HBO) therapy is sometimes used to assist in wound healing after major head and neck cancer surgery. However, there is concern that HBO treatments might enhance the growth of any residual microscopic disease. This was studied in a mouse model of squamous cell carcinoma (SCC). METHODS: SCC-VII/SF tumor cells were cultured, and then injected (3 × 10(3) cells) into C3H/HeJ mice in 5 groups: subcutaneous (SQ) control (n = 13), SQ-immediate (n = 12), SQ-delayed (n = 13), tail vein control (n = 8), and tail vein immediate (n = 9). The 3 experimental groups were subjected to HBO therapy, 2.4 atm for 90 minutes, 5 days per week for 4 weeks, starting on postinjection day 3 ("immediate") or 10 ("delayed"). Tumors in the SQ mice were measured 3 times per week. Lung metastases in the tail vein mice were counted at necropsy. RESULTS: At postimplantation day 28, when the immediate group completed its HBO therapy, the tumor volume in the SQ-immediate group was 49.1% higher than the control group, and the SQ-delayed group was 105.1% higher than controls (p < .05). Two weeks later, the SQ-immediate group and SQ-delayed group tumor volumes were still significantly higher than controls, but the difference was smaller (18.4% and 43.8%, respectively; p < .05 only for the delayed group). The tail vein groups had similar numbers of lung metastases, with a mean of 8.7 metastases in the control group and 9.0 metastases in the HBO group (not significant [NS]). CONCLUSION: This study suggests that HBO therapy does accelerate the growth of microscopic foci of SCCs. This finding differs from some earlier studies and warrants further study.
Subject(s)
Carcinoma, Squamous Cell/pathology , Carcinoma, Squamous Cell/therapy , Head and Neck Neoplasms/pathology , Head and Neck Neoplasms/therapy , Hyperbaric Oxygenation/adverse effects , Animals , Disease Models, Animal , Mice , Mice, Inbred C3H , Squamous Cell Carcinoma of Head and Neck , Tumor BurdenABSTRACT
The major surface glycoprotein (Msg) of Pneumocystis jiroveci (P. jiroveci) is important in the immunopathogenesis of Pneumocystis pneumonia (PcP), but is difficult to study in humans. We generated 3 overlapping recombinant Msg fragments (MsgA, MsgB and MsgC), and analyzed their reactivity with serum samples from 95 healthy blood donors and 94 human immunodeficiency virus (HIV)-infected persons. Reactivity to the Msg fragments varied with HIV infection and prior episodes of PcP but not with geographic origin. Recognition of MsgA was lower-and recognition of MsgB was significantly lower-in HIV(+) serum compared with donor serum. Serum samples from HIV-positive patients with prior PcP recognized MsgC more frequently than did serum samples from those without PcP. None of the serum samples drawn from 9 patients before they had developed PcP recognized MsgC. These data suggest that these novel recombinant proteins are useful for the analysis of antibody responses to Msg.
