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.     

Distinct Pharmacologic Properties of Neuromuscular Blocking Agents on Human Neuronal Nicotinic Acetylcholine Receptors: A Possible Explanation for the Train-of-four Fade

Background: Nondepolarizing neuromuscular blocking agents (NMBAs) are extensively used in the practice of anesthesia and intensive care medicine. Their primary site of action is at the postsynaptic nicotinic acetylcholine receptor (nAChR) in the neuromuscular junction, but their action on neuronal nAChRs have not been fully evaluated. Furthermore, observed adverse effects of nondepolarizing NMBAs might originate from an interaction with neuronal nAChRs. The aim of this study was to examine the effect of clinically used nondepolarizing NMBAs on muscle and neuronal nAChR subtypes.

Methods: Xenopus laevis oocytes were injected with messenger RNA encoding for the subunits included in the human [alpha]1[beta]1[varepsilon][delta], [alpha]3[beta]2, [alpha]3[beta]4, [alpha]4[beta]2, and [alpha]7 nAChR subtypes. The interactions between each of these nAChR subtypes and atracurium, cisatracurium, d-tubocurarine, mivacurium, pancuronium, rocuronium, and vecuronium were studied using an eight-channel two-electrode voltage clamp setup. Responses were measured as peak current and net charge.

Results: All nondepolarizing NMBAs inhibited both muscle and neuronal nAChRs. The neuronal nAChRs were reversibly and concentration-dependently inhibited in the low micromolar range. The mechanism (i.e., competitive vs. noncompetitive) of the block at the neuronal nAChRs was dependent both on subtype and the NMBA tested. The authors did not observe activation of the nAChR subtypes by any of the NMBAs tested.     

Mother's education and perinatal problems in Finland.

This study using nationwide data expands a previous study from one area in Finland. The purpose was to study how perinatal problems (mortality, short gestation, low birthweight and low Apgar scores) vary by mother's social class, which is measured by level of education. Outcomes of all births in the 1987 Medical Birth Register were linked to the 1988 National Education Register with gives the estimated number of years of completed education. In unadjusted analyses, the lowest educational groups (less than 9 years) had the worst results for outcomes other than neonatal mortality. Results in the two highest educational groups (greater than or equal to 13 and 12 years of education) were similar and if anything, better in the second highest group. Excluding twins and adjusting for confounding variables (age, parity, county, urbanization of residence) by logistic regression analysis did not alter the results much. Adjustment for possible mechanisms correlated with social class (marital status, smoking, time of first antenatal visit) decreased the higher occurrence of low birthweight infants in the low educational groups. Reported previous miscarriages were more common in the higher educational groups. Based on the available background characteristics one would expect to have found the usual social gradient in perinatal problems to have persisted between the two highest educational groups. Further studies on factors causing the plateau in the gradient between these groups might be useful.     

Ropivacaine for dental anesthesia: a dose-finding study.

PURPOSE: The purpose of this study was to determine the optimal concentration and volumes of ropivacaine for dental anesthesia as regards onset and duration of action. SUBJECTS AND METHODS: Thirty healthy individuals with a mean age of 32 years participated in the study on a voluntary basis. All subjects received a ropivacaine injection in 1 of 3 randomized concentrations (2.0, 5.0, or 7.5 mg/mL) for infiltration anesthesia and mandibular nerve block in a double-blind manner. The onset time and duration of anesthesia were assessed by electric pulp test, pinprick test of the gingiva, and presence of feeling of numbness of the lip. RESULTS: Regardless of dose, only 5 patients received pulpal anesthesia after infiltration, but all 3 concentrations anesthetized the gingiva and upper lip. The onset of pulpal anesthesia occurred less than 5 minutes after injection and lasted for 4 to 58 minutes. Pinprick anesthesia lasted for 8 to 48 minutes, and numbness of the upper lip lasted 1 to 4 hours. The effectiveness of the mandibular nerve block with regard to pulpal anesthesia was dose dependent. Only ropivacaine at 7.5 mg/mL produced sufficient anesthesia. The onset of pulpal anesthesia occurred less than 10 minutes after injection and lasted for 2 to 6 hours. Pinprick anesthesia lasted for 3 to 6 hours and numbness of the lower lip lasted for 5 to 9 hours. CONCLUSION: This study shows that ropivacaine could be useful as a local anesthetic for mandibular nerve block in dentistry and that the very long duration of both pulpal and soft tissue anesthesia may be favorable in reducing postoperative pain.