1 Theophylline metabolism was studied using seven human cytochrome P-450 isoforms (CYPs), namely CYPlAl, 1A2, 2A6, 2B6, 2D6, 2E1 and 3A4, and microsomal epoxide hydroxylase (EH), expressed in human B-lymphoblastoid cell lines. 2 At a high theophylline concentration of 10 mm four CYPs (lAl, 1A2, 2D6, 2E1) catalyzed the metabolism of theophylline. 3 Theophylline had the highest affinity (apparent Km range 0.2-1.0 mM) for the CYPIA subfamily and the kinetics of metabolic formation mediated by CYP1A2indicated substrate-inhibition (K1 range 9-16 mM). 4 CYP1A2 catalyzed the demethylation of theophylline as well as its hydroxylation, and was associated with the highest intrinsic clearance (1995 1 h-' per mol CYP) to 1,3-dimethyluric acid (DMU). Therefore, this isoform can be considered to be the most important enzyme involved in theophylline metabolism in vitro. 5 CYP2El was responsible for a relatively high intrinsic clearance by 8-hydroxylation (289 1 h-' per mol CYP). The apparent Km value of this reaction was about 15 mm, suggesting that CYP2E1 may be the low-affinity high-capacity isoform involved in theophylline metabolism. 6 The affinity of theophylline for CYPlAl was comparable with that of its homologue 1A2. When induced, the participation of CYPlAl in theophylline metabolism may be important. 7 CYP2D6 played only a minor role and CYP3A4 was not active in the in vitro metabolism of theophylline. 8 Our findings confirm the major role of CYP1A2 in theophylline metabolism and explain why in vivo the elimination kinetics of theophylline are non-linear and in vitro theophylline metabolism by human liver microsomes does not obey monophasic kinetics. 9 The data suggest also that not only tobacco smoking but also chronic alcohol intake may influence theophylline elimination in man as ethanol induces CYP2E1.Keywords theophylline metabolism CYP1A2 CYP2E1 in vitro cDNA expressed microsomes

We present an optical coding technique that enhances the anticounterfeiting power of security holograms. The principle of the technique is based on the moiré phenomenon. The code in the hologram has a phase pattern that is invisible and cannot be detected by optical equipment, so that imitation is extremely difficult. Holographic, photographic, and embossing techniques are used in fabricating coded holograms and decoders.

Abstract. Gastrointestinal stromal tumors (GISTs) are mesenchymal neoplasms that arise in the gastrointestinal tract, accounting for ~1% of gastric malignancies. The present study reports the case of a GIST of the stomach in a 75-year-old man who presented with abdominal distension and anorexia for 1 month. Gastroscopy was unremarkable. Ultrasound and computed tomography (CT) scans showed a giant intraabdominal cystic lesion of unknown origin. The lesion was initially believed to be a duplication cyst, a pancreatic pseudocyst or a liver cyst in the pre-operative diagnosis. Exploratory laparotomy revealed a cystic lesion of the lesser sac originating from the lesser curvature of the stomach. A distal gastrectomy with en bloc resection of the lesion was performed. The intraoperative frozen section showed a spindle-cell GIST and microscopically negative margins. The patient was treated with imatinib for 1 year. The latest CT scan at 14 months post-surgery did not show any recurrence. Although GISTs presenting as predominantly cystic lesions are very rare, they should be considered in the differential diagnosis of cystic lesions of the upper abdomen. IntroductionGastrointestinal stromal tumors (GISTs) are the most frequently occurring mesenchymal neoplasms of the gastrointestinal tract (1). The crude annual incidence of GISTs varies across the globe, although the incidence is ~130 cases per 1 million individuals in a population (2). In total, 50-70% of the tumors originate in the stomach, while 20-30% arise in the small bowel, with the duodenum being the rarest site (1,3). Contrast-enhanced computed tomography (CT) is the imaging method of choice to characterize an abdominal mass, to evaluate its extent, and to determine the presence or absence of metastatic disease (4). The vast majority of GISTs are solid tumors, and cystic change is uncommon (5,6). There is no significant difference between cystic and solid GISTs in terms of the treatment and prognosis. For peritoneal cystic lesions, the diagnosis of GIST is not initially considered. The 5-year survival rate of patients with GIST is ~70% (7).The most common intraabdominal cystic lesion originates from the mesentery or retroperitoneal space (8). Other cystic lesion include duplication cysts, pancreas pseudocysts or liver cysts. The present study reports the case of a large cystic lesion arising from the stomach, which was ultimately diagnosed as a GIST. Case reportA 75-year-old man presented to Kunshan First People's Hospital Affiliated to Jiangsu University (Kunshan, Jiangsu, China) on February 25, 2015 with abdominal distension and anorexia that had persisted for 1 month. There was no history suggestive of gastric outlet obstruction, and no vomiting, melena or constitutional symptoms. The patient had undergone no past surgeries and had no history of pancreatitis. Upon examination, no abdominal mass was palpable. A CT scan of the abdomen was performed, which showed a well-defined exophytic cystic lesion located between the liver and the stomach (Fig. 1). No metas...