Investigations on the photochromic properties of 2,6-bis(5-bromo-2-hydroxybenzylidene)cyclohexanone

The network of chemical reactions of 2,6-bis(5-bromo-2-hydroxybenzylidene)cyclohexanone (BHBC) when subjected to light and different pH values has been investigated. The pH dependent species involved in the chemical network have been identified and characterized by NMR and UV-VIS spectroscopy. Direct pH jumps were carried out by adding a strong acid to equilibrated solutions of trans-chalcone (Ct) forming the flavylium cation which was stable only under extremely acidic conditions (pH < 0.5). The single crystal X-ray study and NMR analysis has confirmed the structure of the new flavylium cation. In the case of a reverse pH jump, the Ct species interconverted instantaneously into deprotonated trans-chalcone (Ct^2-) around pH 12. A new colorless compound 3,11-dibromo-7,8-dihydro-6H-chromeno[3,2-d]xanthene (B-B) isolated from the equilibrated solution of trans-chalcone species in methanol after long periods of time (100 h) under dark conditions has been isolated and fully characterized by NMR and X-ray diffraction. The rate of the reaction increased when the solution of trans-chalcone was exposed to light and the total conversion of Ct into the spiropyran-like compound (B-B) was achieved in about 30 minutes. The B-B form was stable under neutral and basic conditions, while at low pH values it converts into a cationic AH⁺ form.

[Hereditary pancreatitis]

We present the cases of three brothers (a woman and two men) with recurrent attacks of necrotic acute pancreatitis that were treated in our clinic. Two of them have diabetes mellitus controlled through insulin treatment. All patients have presented the first episode of acute pancreatitis around age of 35. We have observed a high level of serum triglyceride at admission, without evidence of lipid disorder. In addition we couldn't identify other causes of these episodes of acute pancreatitis (biliary stones, alcohol, trauma, drugs, lipid disorders). During the last year two members of this family presented recurrent attacks of abdominal pain without any biochemical or imaging signs of acute pancreatitis.

[Gastric stromal tumors--Clinical and histopathological analysis of four cases]

BACKGROUND

The aim of this study is to present our experience concerning a rare form of gastric tumor--gastrointestinal stromal tumor (GIST).

METHODOLOGY

We reviewed data of four patients with gastric stromal tumors, which have been admitted in our department from 1998-2002.

RESULTS

There were two females and two males with age of 75, 70, 65 and 63 years old. The average duration of symptoms until hospital admission was 7 days. During surgery we discovered proximal gastric tumors with 4, 5, 10 and 20 cm in largest diameter. We performed excision of the whole tumor with a security limit of 2 cm or gastric resection (one case), without limphadenectomy. One patient developed an anastomotic fistula with a good evolution under conservative treatment. All patients left the hospital in a good condition. Histopathological and immunohistochemical study diagnosed gastric stromal tumors by identifying the CD 117 maker. Postoperatively neither one of our patients received chemotherapy or radiotherapy. One female and one male patient died of peritoneal metastasis at nine months and respectively two years after operation. The other two patients are in a good condition up to date, without metastasis, one and respectively three years after surgical treatment. CONCLUSIOUS: Correct diagnosis, complete tumor resection and surveillance are essential steps in management of gastric stromal tumors.