LONG‐TERM FOLLOW UP OF PATIENTS WITH SMALL GASTROINTESTINAL STROMAL TUMORS IN THE STOMACH USING ENDOSCOPIC ULTRASONOGRAPHY‐GUIDED FINE‐NEEDLE ASPIRATION BIOPSY

Background: Gastrointestinal stromal tumors (GIST) are one of the most common mesenchymal tumors of the gastrointestinal tract. GIST are defined by positive immunohistochemical staining for KIT or CD34 and thus are generally diagnosed after surgery. Because small GIST are rarely diagnosed before surgery, the clinical course of these small tumors is not clear. The aim of the present study was to follow changes in size and configuration of small GIST that were pathologically confirmed using endoscopic ultrasonography‐guided fine‐needle aspiration biopsy (EUS‐FNAB). Methods: Between July 1997 and December 2003, 16 tumors in 16 patients (10 men and 6 women) with an immunohistochemical diagnosis of GIST were regularly followed in our hospital. The median patient age when EUS‐FNAB was performed was 62 years (range 26–82 years) and the median follow‐up period was 4.9 years (range 0.5–9.6 years). Results: Fourteen tumors showed no remarkable changes in size and shape during follow up compared with the initial diagnosis. Two tumors enlarged: one tumor approximately doubled its diameter in 8 years and the other tumor increased from 1.8 cm at diagnosis to up to 10 cm after only 2 years. Doubling time of the latter tumor was calculated as 3.1 months. Conclusions: We conclude that EUS‐FNAB might be a good modality for final diagnosis of GIST without surgery, and that GIST without rapid growth on follow up can be endoscopically followed.     

Altered interleukin-2 production in schizophrenia: association between clinical state and autoantibody production.

Mitogen-stimulated interleukin-2 (IL-2) production was measured in 122 patients who met Research Diagnostic Criteria for schizophrenia and 98 normal control subjects. The presence of autoantibodies against seven common antigens was also determined. There was no relationship between the presence of circulating autoantibodies and IL-2 production in control subjects. In patients, however, autoantibody-positive, acutely ill patients had significantly lower IL-2 production as compared with other patients and control subjects. Never-medicated patients showed the same trends for decreased IL-2 production in association with autoantibodies. These data suggest that decreased IL-2 production is associated with acute illness in schizophrenic patients who produce autoantibodies, a trait known to be associated with increased vulnerability to autoimmune disease.     

Evaluation of a new enzyme-linked immunosorbent assay test for rotavirus antigen in faeces

A new commercial test for the diagnosis of rotavirus gastroenteritis was assessed. With some modifications it compared favourably with electron microscopy and immunofluorescence.     

Competitive control of the self-renewing T cell repertoire

We develop a mathematical model for the self-renewing part of the T cell repertoire. Assuming that self-renewing T cells have to be stimulated by immunogenic MHC-peptide complexes presented on the surfaces of antigen-presenting cells, we derive a model of T cell growth in which competition for MHC-peptide complexes limits T cell clone sizes and regulates the total number of self-renewing T cells in the animal. We show that for a sufficient diversity and/or degree of cross-reactivity, the total T cell number hardly depends upon the diversity of the T cell repertoire or the diversity of the set of presented peptides. Conversely, for repertoires of lower diversity and/or cross-reactivity, steady-state total T cell numbers may be limited by the diversity of the T cells. This provides a possible explanation for the limited repertoire expansion in some, but not all, mouse T cell re-constitution experiments. We suggest that the competitive interactions described by our model underlie the normal T cells numbers observed in transgenic mice, germ-free mice and various knockout mice.      

A mathematical model of optimized radioiodine-131 therapy of Graves' hyperthyroidism

Background

The current status of radioiodine-131 (RaI) dosimetry for Graves' hyperthyroidism is not clear. Recurrent hyperthyroidism and iatrogenic hypothyroidism are two problems which interact such that trying to solve one leads to exacerbation of the other. Optimized RaI therapy has therefore begun to be defined just in terms of early hypothyroidism (ablative therapy) as physicians have given up on reducing hypothyroidism.

Methods

Optimized therapy is evaluated both in terms of the greatest separation of cure rate from hypothyroidism rate (non-ablative therapy) or in terms of early hypothyroidism (ablative therapy) by mathematical modeling of outcome after radioiodine and critically discussing the three common methods of RaI dosing for Graves' disease.

Results

Cure follows a logarithmic relationship to activity administered or absorbed dose, while hypothyroidism follows a linear relationship. The effect of including or omitting factors in the calculation of the administered I–131 activity such as the measured thyroid uptake and effective half-life of RaI or giving extra compensation for gland size is discussed.

Conclusions

Very little benefit can be gained by employing complicated methods of RaI dose selection for non-ablative therapy since the standard activity model shows the best potential for cure and prolonged euthyroidism. For ablative therapy, a standard MBq/g dosing provides the best outcome in terms of cure and early hypothyroidism.