Complications of intraocular foreign bodies

Intraocular foreign bodies are grave ophthalmic emergencies. In this issue we present the complications that have been reported to the patients with intraocular foreign bodies admitted in the Ophthalmological Hospital from Cluj-Napoca between 1998-2002.     

Effect of sumatriptan in different models of pain in rats

The effect of sumatriptan in two standard algesimetric tests and in a model of cephalalgia was evaluated in rats. The pain threshold was measured by the hot-plate and the writhing tests; cephalalgia was produced by injecting bradykinin (10 μg in a volume of 10 μl) into a common carotid artery. Sumatriptan was subcutaneously (s.c.) injected at the doses of 4, 8, 24 or 42 mg/kg; morphine (5 or 10 mg/kg s.c.) and indomethacin (5 or 10 mg/kg s.c) were used as standard analgesic drugs. Sumatriptan had no analgesic activity either in the hot-plate test or in the writhing test. On the other hand, at 24 and 42 mg/kg it dose-dependently reduced the response to the intracarotid injection of bradykinin (vocalization and tachypnea), this effect being prevented by the 5-HT_1B receptor antagonist, isamoltane. The 5-HT_1D receptor antagonist BRL15572 prevented the effect of sumatriptan on bradykinin-induced tachypnea, but not the effect of sumatriptan on bradykinin-induced vocalization. These data demonstrate that sumatriptan is significantly effective in a reliable animal model of cephalalgia, while having no systemic analgesic activity.     

1-Thioangelicin: crystal structure, computer-aided studies and photobiological activity

1-Thioangelicin is a furocoumarin analog synthesized to investigate the role of the substitution of sulfur for oxygen in the parent compound angelicin. The compound was examined by X-ray diffraction, and its interaction with DNA, both in the dark and by UVA irradiation, studied by means of linear flow dichroism, chromatography and (1)H NMR. Further insight into the steric and electronic features of 1-thioangelicin has been reached through theoretical calculations, including molecular mechanics optimization, docking studies and frontier molecular orbital investigations. The experimental data indicate that thioangelicin is able to intercalate in the DNA helix and subsequent irradiation yields a cis-syn adduct, in agreement with theoretical calculations within the lower/higher singly occupied molecular orbital formalism. Antiproliferative activity has been assessed on Balb/c 3T3 cultured cells.     

Synthesis and biological evaluation of analogues of 7-chloro-4,5-dihydro-4- oxo-8-(1,2,4-triazol-4-yl)-1,2,4-triazolo[1,5-a]quinoxaline-2-carboxylic acid (TQX-173) as novel selective AMPA receptor antagonists

In recent papers (Catarzi, D.; et al. J. Med. Chem. 2000, 43, 3824-3826; 2001, 44, 3157-3165) we reported chemical and biological studies on 4,5-dihydro-4-oxo-1,2,4-triazolo[1,5-a]quinoxaline-2-carboxylates (TQXs) bearing different nitrogen-containing heterocycles at position-8. In particular, from these studies it emerged that both the 7-chloro-4,5-dihydro-4-oxo-8-(1,2,4-triazol-4-yl)-1,2,4-triazolo[1,5-a] quinoxaline-2-carboxylic acid TQX-173 (compound B) and its corresponding ethyl ester (compound A) were the most active and selective compounds of this series. In pursuing our investigation on the structure-activity relationships of these TQX derivatives, different electron-withdrawing groups (CF(3), NO(2)) were introduced at position 7 on the TQX ring system, replacing the 7-chloro substituent of B and of other selected 8-heteroaryltriazoloquinoxaline-2-carboxylates previously described. All the newly synthesized compounds were biologically evaluated for their binding at the Gly/NMDA, AMPA, and KA high-affinity receptors. Gly/NMDA binding assays were performed to assess the selectivity of the reported compounds toward the AMPA receptor. Compounds endowed with micromolar binding affinity for the KA high-affinity binding site were also evaluated for their binding at the KA low-affinity receptor. Some selected compounds were also tested for their functional antagonist activity at the AMPA and NMDA receptor-ion channel complex. The results obtained in this study have pointed out that 4,5-dihydro-7-nitro-4-oxo-8-(3-carboxypyrrol-1-yl)-1,2,4-triazolo[1,5-a]quinoxaline-2-carboxylic acid (9b) and its corresponding ethyl ester (9a) are the most potent and selective AMPA receptor antagonists reported to date among the TQX series.     

Benzoxepin-derived estrogen receptor modulators: a novel molecular scaffold for the estrogen receptor

We present and examine the efficacy of a novel benzoxepin-based scaffold for modulation of the human estrogen receptor. Receptor tolerance of this new molecular scaffold is examined through presentation of experimentally determined antiproliferative effects on human MCF-7 breast tumor cells and measured binding affinities. The effect of functional group substitution on the benzoxepin scaffold is explored through a brief computational structure-activity relationship investigation with molecular simulation.     

1,2,4-triazolo[4,3-a]quinoxalin-1-one moiety as an attractive scaffold to develop new potent and selective human A3 adenosine receptor antagonists: synthesis, pharmacological, and ligand-receptor modeling studies

In the past few years much effort in our laboratory has been directed toward the study of adenosine receptor antagonists, and recently we focused our attention on 2-aryl-1,2,4-triazolo[4,3-a]quinoxaline-1,4-diones and 2-aryl-1,2,4-triazolo[4,3-a]quinoxalin-4-amino-1-ones, some of which were potent and/or selective A(3) receptor antagonists. In the present paper, a new series of triazoloquinoxaline derivatives is described. Most of the new compounds, biologically evaluated in radioligand binding assays at bovine (b) A(1) and A(2A) and at human (h) A(1) and A(3) adenosine receptors, showed high hA(3) adenosine receptor affinity and selectivity. In particular, 2-(4-nitrophenyl)-1,2,4,5-tetrahydro-1,2,4-triazolo[4,3-a]quinoxaline-1,4-dione (1), also tested at the hA(2A) ARs, shows the best binding profile with a high hA(3) affinity (K(i) = 0.60 nM) and strong selectivity vs hA(1) and vs hA(2A) receptors (both selectivity ratios greater than 16 600). To interpret our experimental results, we decided to theoretically depict the putative transmembrane binding motif of our triazoloquinoxaline analogues on hA(3) receptor. Structure-activity relationships have been explained analyzing the three-dimensional structure of the antagonist-receptor models obtained by molecular docking simulation.     

Small molecule antagonists of the tachykinin NK 2 receptor

The NK(2) receptor (member of the tachykinin receptor family) is mainly located in the smooth muscle of the urinary, respiratory and gastrointestinal tracts, with limited presence in the CNS. This has raised interest in tachykinin NK(2) receptor antagonists for the treatment of urological disorders, asthma. This review outlines progress done after 1998 in the field of NK(2) small molecule antagonists, both acting on the NK(1)/NK(2), NK(2)/NK(3), NK(1)/NK(2)/NK(3) receptors and selective for the NK(2) one.     

Oxygen activation by photoexcited protoberberinium alkaloids from Mahonia aquifolium

Protoberberinium salts, i.e. berberine (I), palmatine (II) and jatrorrhizine (III) prepared from Mahonia aquifolium (Pursh) Nutt. belong to isoquinoline alkaloids possessing interesting biological activity (e.g. antibacterial, antimalarial, antitumor). The characteristic UV/Vis absorption band maxima of I-III iodide salts were found in regions 350 and 425 nm in dimethylsulfoxide (DMSO) and ethanol solvents, and were only negligibly influenced by substitution changes on the C-2 and C-3 positions. The fluorescence intensity of protoberberinium salts monitored in ethanol solutions was significantly lowered by iodide counter-ions, and decreased in the order berberine > palmatine > jatrorrhizine. EPR spectroscopy supplied evidence of the formation of super-oxide anion radicals and singlet oxygen upon irradiation of berberine in oxygenated DMSO solvent. The photochemical generation of O(2) (.-) and (1)O(2) in DMSO solutions of palmatine and jatrorrhizine was substantially lower, and probably reflected the replacement of a photolabile methylenedioxy group at C-2 and C-3 positions in the berberine molecule by two methoxy groups in palmatine, and methoxyl (C-2) and hydroxyl (C-3) substitution in jatrorrhizine. Additionally, the powder EPR spectra of protoberberinium iodides I-III measured at 290 K revealed the presence of single-line EPR signals (g(eff) = 2.0044), which were attributed to hydroperoxidic structures produced by the autoxidation process. The photochemical reactions of protoberbenium salts producing reactive oxygen species after UVA excitation should be integrated in biological activity investigations, as well as in their applications in skin disorder treatment.     

Efficacy and feasibility of standard procarbazine, lomustine, and vincristine chemotherapy in anaplastic oligodendroglioma and oligoastrocytoma recurrent after radiotherapy. A Phase II study

BACKGROUND: To the authors' knowledge, there is a scarcity of accurate data regarding the feasibility of standard chemotherapy with procarbazine, lomustine, and vincristine (PCV) in a homogeneous series of patients with primary anaplastic oligodendroglioma (AO) and oligoastrocytoma (AOA) that was recurrent after surgery and standard radiotherapy. The aim of the current study was to evaluate the overall response rate, toxicity, and time to progression (TTP) with the use of standard PCV in this setting. METHODS: Between November 1994 and September 2000, 37 patients were enrolled in the current study. Of these, 23 had AO (62%) and 14 had AOA (38%). All patients received standard PCV comprised of lomustine (110 mg/m2) on Day 1, procarbazine (60 mg/m2) on Days 8-21, and vincristine (1.4 mg/m2, maximum total 2 mg) on Days 8 and 29. Cycles were repeated every 6 weeks. RESULTS: There were 11 complete responses (CR; 29.7%) and 11 partial responses (PR; 29.7%) reported and 8 patients had stable disease (SD; 21.6%). The response rate was higher in patients with AO compared with patients with AOA (77.2% vs. 22.7%; P = 0. 02). The median TTP, which was 12.3 months overall, was 30.3 months in patients who achieved a CR, 19.1 months in patients who achieved a PR, and 6.1 months in patients with SD. The median TTP was 18.6 months in AO patients and 6.14 in AOA patients. There were no cases of severe toxicity reported although in 16 patients (43%) who were free of disease progression, PCV was discontinued because of toxicity or inadequate recovery after 2 weeks of delay. CONCLUSIONS: PCV chemotherapy was reported to achieved a high response rate and TTP but incurred a high risk of persistent toxicity.