Malignant nerve sheath tumors of the head and neck: a combined experience from two university hospitals.

Malignant schwannoma is an aggressive neoplasm whose cell of origin and histologic characteristics remain controversial. Despite advances in diagnostic techniques, the natural history of this tumor remains uncertain. The charts of all patients with malignant schwannoma who were treated at the UCLA Center for the Health Sciences and the University of Iowa Hospital and Clinics were retrospectively reviewed. Sixteen patients received surgery and radiotherapy in combination or as sole therapy. Irrespective of treatment modality, prognosis was poor with an overall survival of 15%. Recent advances in imaging and histologic techniques that assist in establishing the diagnosis and delineating tumor location are discussed. In addition, the literature pertaining to malignant schwannoma of the head and neck is reviewed.

Tumor necrosis factor and chemotherapeutic agents. Potentiation of cytotoxicity with interferon gamma.

This study examined combinations of the recombinant human cytokines, tumor necrosis factor alpha and interferon gamma, with doxorubicin and dactinomycin as well as other drugs on six squamous cell carcinoma cell lines of head and neck origin using the 3(4,5-dimethylthiazol-2-yl)2,5-diphenyl-tetrazolium bromide proliferation assay. Interferon gamma significantly enhanced the cytotoxicity of tumor necrosis factor alpha with dactinomycin on all six cell lines investigated, while in four of six cell lines the cytotoxicity of tumor necrosis factor alpha with doxorubicin was significantly augmented by interferon gamma. Additional experiments showed no effect with either cytokine in combination with cisplatin, fluorouracil, methotrexate, or etoposide. These data demonstrate that human recombinant cytokines in concert with certain drugs improve in vitro cytotoxicity and may have a potential for improving in vivo therapy.

Tumor necrosis factor and cytotoxic agents. Effect on squamous carcinoma lines.

The cytotoxicity of dactinomycin (actinomycin D), doxorubicin hydrochloride (Adriamycin), cisplatin, fluorouracil, and methotrexate alone and in combination with recombinant human tumor necrosis factor (rHuTNF) on human squamous cell carcinoma lines was studied by an MTT proliferation assay. The rHuTNF alone caused no inhibition after 24 to 72 hours. All lines investigated showed a dose-dependent response to dactinomycin and doxorubicin. Potentiation of dactinomycin and doxorubicin cytotoxicity occurred with four of six cell lines following incubation of rHuTNF and the drug. No synergistic effect on cytotoxicity was seen with rHuTNF and any chemotherapeutic agent on two cell lines. The addition of rHuTNF did not augment the cytotoxic effect seen with cisplatin, methotrexate, or fluorouracil on any cell line. These results show that rHuTNF can enhance the cytotoxic effect of certain chemotherapeutic agents on squamous cell lines in vitro.

The effect of hyperbaric oxygen on growth of human squamous cell carcinoma xenografts.

Hyperbaric oxygen is an important adjunct to the treatment of patients with head and neck cancer with existing or recurrent wound healing problems. Anecdotal clinical observations and a recent study of chemically induced oral cancer in hamsters have raised concern that hyperbaric oxygen therapy may accelerate tumor growth in such patients. This study evaluated the effect of hyperbaric oxygen therapy on the growth of human squamous cell carcinoma xenografts in a proved animal model. Fresh tumor specimens from three patients with head and neck squamous cell carcinoma of varying degrees of differentiation were first subcutaneously transplanted into a nude mouse host. Growing xenografts were then transplanted into one of three mouse groups. Half of the mice in each group were given hyperbaric oxygen therapy. The transplant volume as an index of tumor growth was measured in controls and mice given hyperbaric oxygen therapy six times during the 3-week course. Xenograft growth was almost linear in all mice. No statistical difference in overall group mean growth rates was observed in mice given hyperbaric oxygen or control mice regardless of the degree of tumor differentiation. Xenograft tissue from all mice was microscopically examined for tumor mitotic indices and degree of differentiation. This study suggests that hyperbaric oxygen therapy has no effect on established tumor xenograft growth.

Seasonal variations in the transfer of 137Cs and 40K to pasture grass and its ingestion by grazing animals.

Samples of grass and sheep faeces were taken monthly over a 12-month period from three pasture sites. Biomass, 137Cs and 40K were measured. The activity concentration of these two radionuclides in grass was influenced by season and soil type. The seasonal patterns of 137Cs and 40K transfer to grass were inversely related, but evidence is presented which suggests that soil contamination of grass samples contributed to the 137Cs and 40K activity concentrations of the grass and augmented the difference between their patterns of transfer. This was influenced by season, climate and farm management. A parallel seasonality was identified in the 137Cs activity concentration of the faeces of sheep grazing these pastures. This was not observed for 40K in sheep faeces.

Assessment of the role of soil adhesion in the transfer of 137Cs and 40K to pasture grass.

137Cs and 40K were analyzed in pasture grass and soils throughout a 12-month period. The titanium content of the samples was determined as a marker of soil contamination of the grass samples. The 137Cs activity concentration in the grass was closely correlated with titanium and both increase in the winter months suggesting that increased soil contamination of grass is responsible for the increased 137Cs activity concentration observed at this time. The method greatly overestimates the contribution made by soil to the 137Cs activity concentrations of the grass samples and the results are highly variable. Some problems associated with the method are discussed and it is proposed that this method is unreliable.

Squamous cell carcinoma in an inverted papilloma of the buccal mucosa.

Inverted papillomas of the oral cavity are rare lesions. Although in the seven oral cases previously reported the lesions were benign, approximately 10% to 15% of inverted papillomas of the nasal cavity and paranasal sinuses develop or are associated with squamous cell carcinoma. This report presents a case of squamous cell carcinoma arising in an inverted papilloma of the buccal mucosa. Histologically, this lesion demonstrated the morphologic features of inverted papilloma in the superficial portion, and squamous carcinoma in deeper sections. This case suggests that although rare, inverted papillomas of the oral cavity should be considered potentially malignant or capable of harboring a malignancy.

Assessment of immunocompetent cells in patients with head and neck squamous cell carcinoma.

Patients with squamous cell carcinoma of the head and neck have impaired T cell function and poor tumor-specific responsiveness. Disproportionate levels of circulating immunocompetent cells could be one reason for this diminished immunity. In this study, a panel of monoclonal antibodies and flow cytofluorometry were used to define the relative proportions of selected immune cell populations. We detected a deficiency of the interleukin-2-producing subset of T helper-inducer cells (TH 5.2+) in these patients. Our data showed no significant differences in circulating levels of total T cells, T cell subsets, B cells, monocytes, or natural killer cells when compared to age, alcohol- and tobacco-use matched controls.

Long-term trends of radiocesium activity concentrations in vegetation in Irish semi-natural ecosystems.

137Cs activity concentrations were determined in vegetation from four Irish blanket bog ecosystems during the summer months of 1989-1997. The dominant and abundant vegetation species were sampled at each site and the data were used to estimate long-term trends of 137Cs activity concentrations. A general decline in the 137Cs activity concentrations in vegetation was observed from all sites sampled. The fastest and most consistent long-term rates of 137Cs decline were observed in the bryophyte and lichen vegetation group with 137Cs effective half-life (T ef) values of 2.2 to 10.7 y. The ericoid group with the exception of one case also showed a significant long-term decline in 137Cs activity concentrations with T ef values of 3.5 to 12.4 y as did the rush species Juncus squarrosus (T ef range 9.3 to 12.8 y). The sedge and grass groups showed the slowest and the least consistent rates of 137Cs decline, with T ef values of 2.9 to 59.8 y. Preliminary evaluation of 137Cs activity concentrations in sheep from some of the studied sites suggests that the decline found in vegetation is reflected in sheep.

Nuclear magnetic resonance spectroscopy of plasma for the detection of head and neck cancer.

The plasma of 15 normal volunteers, four patients with benign head and neck disease, and 12 patients with biopsy proven head and neck malignancies were evaluated using water-suppressed nuclear magnetic resonance (NMR) spectroscopy. While the mean full width at half height (HHLW) of the NMR spectra showed a significant difference between groups (P less than .05), the predictive value of a positive test was only 57% the sensitivity was only 33%, and individual values in all groups demonstrated considerable overlap. The mean HHLW of the control group was 38.5 Hz +/- 3.5 compared with 35.2 Hz +/- 4.7 for the cancer group and 35.0 Hz +/- 10 for the benign disease group. This method was not able to distinguish patients with malignancy from those with benign disease or controls. Its use as a specific screening method for head and neck malignancy cannot be recommended.

Effects of topography on caesium-137 in montane peat soils and vegetation.

This study investigated the relationship between altitude and 137Cs fallout in soils and plants. The soils and plants, Calluna vulgaris, Erica cinerea and Molinia caerulea, were sampled across a transect of two valleys in north-western Ireland. The results provided evidence that greater 137Cs deposition to soils occurred at higher altitudes, and the data supported the findings of a previous investigation in the same area. A valley effect, whereby greater concentrations of 137Cs accumulated in plants on the lower altitudes of the valley floors, was shown to be significant. Deposition values for total 137Cs in soils were not correlated with plant concentrations, although a relationship between concentrations in C. vulgaris and M. caerulea was found to be statistically significant. No relationship was observed between the 137Cs from weapons fallout with that of Chernobyl origin in the 0-10 cm depth soils, although a significant correlation emerged between the same two components measured in C. vulgaris. The results suggest that existing definitions of concentration ratios and transfer factors are, for many reasons, inappropriate for studies of soil to plant transfer of 137Cs in peatland ecosystems.