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.     

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.      

Isolation and characterization of Mycoplasma sphenisci sp. nov. from the choana of an aquarium-reared jackass penguin (Spheniscus demersus)

Strain UCMJ was isolated from the choana of a jackass penguin (Spheniscus demersus) with recurrent mucocaseous choanal discharge. Isolation of this mycoplasma expands the known range of species hosting mycoplasmas. The name Mycoplasma sphenisci sp. nov. is proposed for this new species, for which strain UCMJ is the type strain.     

Percepciones estudiantiles sobre las propiedades del examen clínico objetivo estructurado en Uruguay. Disponiendo un cuestionario válido para analizar la factibilidad del nuevo formato durante la transición curricular

Introduction

Although an objective structured clinical examination (OSCE) format has been applied in Uruguay since 2004, and providing reliable performance measures, perceptions of it properties and level of student satisfaction have not been determined.

Role of risperidone in bipolar II: an open 6-month study

BACKGROUND: Since treatment approaches thought to be useful for mania are presumably suitable for hypomania as well, little systematic research has been done on the treatment of hypomanic episodes and their long-term outcome. As systematic trials have shown that the atypical antipsychotic risperidone may be effective and safe in the treatment of acute mania, we decided to conduct an open-label study of its effectiveness and tolerability in hypomania associated with bipolar II. METHODS: Forty-four DSM-IV bipolar II patients with Young Mania Rating Scale (YMRS) scores above 7 were included and followed-up for 6 months. Efficacy was measured by means of the YMRS and the Clinical Global Impression for Bipolar Disorder (CGI-BD). Treatment-emergent depression was measured by the Hamilton Depression Rating Scale (HDRS-17), and the Udvalg for Kliniske Unders?gelser (UKU) subscale was used for neurological/extrapyramidal side-effects. RESULTS: Thirty-four patients completed the trial. The mean dose of risperidone at endpoint was 2.8 mg/day. Last observation-carried-forward analysis showed significant reduction of YMRS scores from the first week of treatment, which continued until the endpoint (P<0.0001). At 6-month follow-up, 60% of patients were assymptomatic according to the CGI. The 32% who received risperidone in monotherapy seemed to respond equally well. Risperidone, as used in this study, appeared to be most protective against hypomanic than depressive recurrences. Nine patients (12%) had a depressive relapse during 6-month follow-up, one patient (2%) had an hypomanic relapse and another (2%) had both. No patients developed tardive dyskinesia during the duration of the study. Although most patients received risperidone in combination with standard mood-stabilizers, only three patients discontinued risperidone because of other side-effects. LIMITATIONS: In the absence of a placebo arm, it is uncertain to what extent the foregoing results could be ascribed to spontaneous remission of bipolar II disorder. CONCLUSIONS: Risperidone, either in combination with mood-stabilizers or alone was well-tolerated in bipolar II patients, who presented in a hypomanic state, and appeared efficacious. Further controlled research on the role of atypical antipsychotics in the treatment of less-than-manic forms of bipolar illness is warranted.