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.     

Gunshot wounds to the spine associated with a perforated viscus

The cases of 42 patients with low-velocity gunshot wounds to the spine with an associated perforated viscus were reviewed. All viscus perforations occurred prior to the spinal injury. There were a total of 51 perforations, including 14 of the colon, 15 of the small bowel, 15 of the stomach, five of the esophagus, and two of the pharynx. All patients had significant neurologic deficits, with 23 patients suffering a complete neurologic injury. Average clinical follow-up was 18 months (range: 4-64 months). Only three patients developed documented spinal or paraspinal infections. One case of acute meningitis occurred after an isolated stomach perforation, while two other patients developed psoas abscesses after colon injuries. The roles of initial antibiotic therapy and of early bullet removal were evaluated in regard to infection. An extended course of broad spectrum antibiotics combined with bedrest appeared to significantly reduce the risk of spinal or paraspinal infection as compared with a previous study. Early bullet removal did not appear to be a significant factor in the prevention of infection. Prospective studies are needed to accurately delineate the role of initial antibiotic therapy for the prevention of spinal infection in these injuries.     

The effect of the halovest and body position on pulmonary function in quadriplegia

Pulmonary function (vital capacity) was measured in ten quadriplegics and ten normal subjects in the following situations: supine, sitting, supine with a halovest, and sitting with a halovest. When changing from the supine to sitting positions, vital capacity decreased in the quadriplegics and increased in normal subjects. The halovest significantly reduced the vital capacity in normal subjects, but had much less of a detrimental effect in quadriplegics. As a result of this prospective, controlled study, we conclude the following: (a) the compromised state of pulmonary function in quadriplegics is not a contraindication for the use of a halovest, (b) the halovest causes a significant (p less than 0.01) restriction in vital capacity in able bodied subjects, and (c) when tenuous pulmonary function exists in a quadriplegic, pulmonary mechanics are better in the supine position.     

Pigmentary changes in rat oral mucosa following antimalarial therapy

Pharmacogenic pigmentation of the oral mucosa has been reported following the use of a number of anti-malarial drugs. The nature and distribution of the pigment is inconclusive in the literature. The aim of the present study was to document pigment deposition within the oral mucosa of DA rats following prolonged chloroquine and pyrimethamine administration. The drugs were given as a combined dosage and separately to different groups via stomach gavage tube. After 12 weekly administrations the palatal mucosa was examined histochemically and ultrastructurally for changes in numbers and size of active melanocytes using the dopa-oxidase technique. The serum was analysed for changes in ACTH and testosterone levels. Morphometric analysis of cells incubated for dopa-oxidase showed a significant increase in the size of dopa positive cells with both drugs but an increase in the number of active melanocytes with chloroquine only. Serum levels of ACTH remained unchanged with both drugs but pyrimethamine caused an elevation in testosterone.     

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.