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At least 235 records · Page 13Linked to original sources
PubMed2000

Perfluoroperhydrophenanthrene versus perfluoro-n-octane in vitreoretinal surgery.

PURPOSE: To compare two perfluorocarbon liquids, perfluoroperhydrophenanthrene (Vitreon) and perfluoro-n-octane (PFO), regarding (1) ease of removal at the time of surgery and (2) efficacy and safety. DESIGN: Retrospective, nonrandomized, comparative trial. PARTICIPANTS: Two hundred sixty-four patients. METHODS: All medical records of patients who participated in either the Vitreon (n = 142) or the PFO (n = 122) multicenter trials at the Wilmer Eye Institute were reviewed. Patients in the two groups were compared with respect to presence and amount of postoperative perfluorocarbon. Safety and efficacy of the two perfluorocarbon liquids were evaluated in the subset of patients undergoing surgery for retinal detachment with PVR grade C or more, who had at least 6 months of postoperative follow-up (n = 46 in the Vitreon group and n = 55 in the PFO group). Best-corrected visual acuity, intraocular pressure, and status of the cornea, lens, and retina after 3, 6, and 12 months of follow-up were compared in the two groups. MAIN OUTCOME MEASURES: Percentage of eyes with retained perfluorocarbon, final visual acuity, final retinal attachment rate. RESULTS: At the 6-month postoperative visit, retained Vitreon or PFO was detected in 8.4% and 4% of the eyes, respectively (P < 0.05). No statistically significant difference was found between the two perfluorocarbons in attachment rate or visual acuity after 6 and 12 months. After 6 months, the retina was attached in 71.7% of the eyes in which Vitreon was used and in 78.3% of the eyes in which PFO was used (P = 0.81). Visual acuity improved or remained stable in 80% of the Vitreon group eyes and in 74.5% of the PFO group eyes (P = 0.75). No statistically significant difference was found in final visual acuity or intraocular pressure between the two groups after 6 or 12 months. There was a tendency at the 12-month follow-up examination for the cornea to remain clearer in the Vitreon group (P = 0.01). CONCLUSIONS: Although PFO was easier to visualize and remove completely from within the eye at the time of surgery, the efficacy in terms of retinal attachment and final visual outcome was similar between the Vitreon and PFO groups.

Adolescent↗
PubMed2001

Clinicopathologic findings in eyes with retained perfluoro-n-octane liquid.

OBJECTIVE: To describe the clinical and histopathologic findings in five eyes with retained perfluoro-n-octane (PFO) liquid after retinal reattachment surgery. DESIGN: Retrospective, noncomparative, clinicopathologic case series. PARTICIPANTS: Surgical specimens from five eyes were studied. METHODS: Surgical specimens from eyes with prior intraoperative PFO use submitted to the W. Richard Green Eye Pathology Laboratory at the Wilmer Ophthalmological Institute were identified and reviewed. MAIN OUTCOME MEASURES: Histopathologic analysis and energy dispersive spectroscopy identified intracellular vacuoles containing PFO. RESULTS: Five cases were identified. Three specimens were obtained at the time of further surgery for recurrent retinal detachment; one at repeat penetrating keratoplasty, and one at removal of retained PFO. Each eye had macroscopic white flake-like material on intraocular structures noted before or during surgery. Histopathologic analysis disclosed an inflammatory response featuring macrophages with intracellular vacuoles containing PFO. Removal of the PFO in all five eyes combined with repeat retinal reattachment surgery in three eyes resulted in resolution of the inflammatory response. CONCLUSIONS: Retention of PFO after surgery elicits an inflammatory response. We suspect that young patients, those with considerable residual vitreous gel, and eyes with larger amounts of retained PFO may be at higher risk for this complication.

Adolescent↗
PubMed1991

Perfluoro-octane in the treatment of giant retinal tears with proliferative vitreoretinopathy.

Giant retinal tears complicated by proliferative vitreoretinopathy (PVR) pose one of the more complex problems in vitreoretinal surgery. The authors developed a technique using perfluoro-octane, a temporary vitreous substitute that is heavier than water, combined with vitrectomy, scleral buckling, fluid-gas exchange, and direct manipulation of the retina to treat these cases. Ten eyes with giant retinal tears and grade D-1 PVR or worse were treated. In all eyes, the retina was successfully reattached at the end of surgery. Nine of the ten retinas remained attached after 6 months of follow-up. Five eyes required a total of six reoperations for epiretinal membrane formation without retinal detachment. The one eye in which the retina did not remain reattached developed severe recurrent PVR and iris neovascularization. Visual acuity improved in 8 of 10 eyes. Final visual acuity was 20/400 or better in 8 of 10 eyes, and 20/80 or better in 4 eyes.

Adult↗
PubMed1992

Management of giant retinal tears without scleral buckling. Use of radical dissection of the vitreous base and perfluoro-octane and intraocular tamponade.

The introduction of intraoperative perfluorocarbon liquids in the management of giant retinal tears has allowed exact anatomic reapposition of the retina and the giant retinal tear. Therefore, the authors managed 11 eyes with giant retinal tears and no proliferative vitreoretinopathy without scleral buckling. Maximum removal of the basal vitreous gel was performed in all cases, and perfluoro-octane was used intraoperatively to unfold the inverted posterior flap and reattach the retina completely. Endophotocoagulation was applied to the edges of the tear and perfluoropropane or silicone oil was used as an intraocular tamponade. Although 1 eye required reoperation for a redetachment from posterior proliferative vitreoretinopathy, all retinas were reattached with final visual acuity of 5/200 or better in 9 eyes. Eight additional major procedures were necessary in seven eyes: removal of silicone oil in four (with removal of perisilicone proliferation in three), repeat vitrectomy and membrane removal with photocoagulation twice in one eye, cataract extraction in one eye, and removal of a macular pucker in one eye. Four eyes required postoperative fluid-gas exchange and three eyes had tissue plasminogen activator injections into the anterior chamber for postoperative fibrin reactions.

Adolescent↗
PubMed2001

3,8-diazabicyclo--[3.2.1]-octane derivatives as analogues of ambasilide, a Class III antiarrhythmic agent.

Ambasilide, a representative of Class III antiarrhythmics, was reported to prolong the cardiac action potential duration in the dog, with little or no effect on Ca and Na currents. We synthesised a series of ambasilide analogues, having the 3,8-diazabicyclo-[3.2.1]-octane moiety instead of the 3,7-diazabicyclo-[3.3.1]-nonane present in ambasilide. The compounds were tested both in vitro extracellular electrophysiological assays and by the conventional microelectrode technique. Most of them lengthened the effective refractory period (ERP) with no change or slight increase on the impulse conduction time (ICT). Similarly some of the tested compounds lengthened the action potential duration (APD), a typical Class III feature, without exerting any significant effect on the maximal rate of depolarization, therefore apparently lacking Class I antiarrhythmic activity.

Aminobenzoates↗
PubMed1999

2,7-diazabicyclo[3.3.0]octanes as novel h5-HT receptor agonists.

The conformational restriction of a (benzylamino)methyl substituted pyrrolidine to form 2,7-diazabicyclo[3.3.0]octanes has led to a series of compounds with high affinity at the h5-HT1D receptor as well as dramatically increased concentrations in the hepatic portal vein following oral administration.

Administration, Oral↗
PubMed2000

Chiral gas chromatographic separation of 2-oxabicyclo[3.3.0]octane derivatives and their synthetic precursors.

Chiral GC separation of (+/-)-2-allyl-2-carboethoxycyclopentanone (9) and the alcohols (+/-)-3-(hydroxymethyl)-5-carboethoxy-2-oxabicyclo[3.3.0]octane (7), (+/-)-2-allyl-2-carboethoxycyclopentanol (8), and their acetylated and trifluoroacetylated derivatives were investigated on three derivatized beta-cyclodextrins (CDs) diluted in SE-54 or 1701-OH: 2,3,6-tri-O-methyl-beta-CD (PMCD); 2,3-di-O-methyl-6-O-(tert-butyldimethylsilyl)-beta-CD (DIMETBCD); 2,3-di-O-acetyl-6-O-(tert-butyldimethylsilyl)-beta-CD (DIACTBCD). The understanding of these chiral separations is extremely relevant, since cyclopentanic and bicyclic cyclopentanic rings are common structural features of many important natural products and new pharmaceutical drugs. In general DIMETBCD diluted in SE-54 showed the best chiral resolution to alcohols 7 and 8 and only DIACTBCD showed enantioselectivity to 9. Hydrogen bonds prediction and dipole moments data were obtained by molecular modeling calculations for 7ab and 8ab and Ac and TFA derivatives. Comparison of these data with the chromatographic parameters for the related compounds were used to explain the differences of their elution orders and diastereo- and enantiomeric separations on the above chiral stationary phases (CSPs). The results suggest that the CSPs enantioselectivities are not affected by the carboethoxy-functionalized cyclopentanic and bicyclic cyclopentanic rings themselves but mainly by the functional group on the other stereogenic center.

Bridged Bicyclo Compounds, Heterocyclic↗
PubMed2004

Recent highlights in electrophilic fluorination with 1-chloromethyl-4-fluoro- 1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate).

Synthetic and structural aspects of organofluorine compounds continue to be the focal points of vigorous research activities, as evidenced by the appearance of a large number of publications. Among the various useful methodologies for the introduction of fluorine into organic molecules, electrophilic fluorination is a promising and exciting area of research. While a variety of electrophilic fluorinating reagents are available, currently 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (Selectfluor) provides a remarkably straightforward and effective route. The breadth of applications realizable from this reagent in its role as a key electrophilic fluorinating reagent is highlighted here. This Account covers the literature for electrophilic fluorination reactions that employ Selectfluor during the period January 1999-January 2003.

Diazonium Compounds↗
PubMed1981

Interaction of 2-aminobicyclo[3.2.1]octane-2-carboxylic acid with the amino acid transport systems of the sarcoma 37 murine ascites tumor cell.

The relatively broad and overlapping specificities of amino acid transport systems have made the synthesis of analogues specific to single transport systems desirable. The analogue in general use as a specific substrate for transport system L has been 2-aminobicyclo[2.2.1]heptane-2-carboxylic acid (BCH). The affinity of BCH for the binding site of system L has been shown to be less than that of the natural substrate, leucine. Earlier studies from this laboratory suggested that higher homologues in a series could have greater affinity for system L. A higher homologue of BCH, 2-aminobicyclo[3.2.1]octane-2-carboxylic acid (ABOCA), has been synthesized and studied as a substrate and competitor for amino acid transport systems of the sarcoma 37 (S37) ascites cell. ABOCA inhibited the transport system dominant in the low concentration region for histidine uptake (system L) but had no effect on the uptake of labeled N-methyl-alpha-aminoisobutyric acid (MeAIB). MeAIB had no effect on labeled ABOCA uptake in S37 cells. ABOCA inhibited the uptakes of labeled leucine and labeled BCH competitively. Leucine, histidine, and BCH inhibited the uptake of labeled ABOCA competitively. Typical L system substrates demonstrated exchange effects with labeled ABOCA. The b isomer of ABOCA demonstrated slightly greater affinity for system L than did the a isomer. We conclude that ABOCA is an analogue restricted to interaction with amino acid transport system L, that it has greater affinity for system L than does BCH, and that its selection for system l is determined principally by an apolar interaction with steric considerations secondary.

Amino Acids↗
PubMed2005

Multicomponent domino reaction from beta-ketoamides: highly efficient access to original polyfunctionalized 2,6-diazabicyclo[2.2.2]octane cores.

We describe a new multicomponent domino reaction from beta-ketoamides, involved as substrates and as nucleophilic partners. We obtain highly functionalized and original 2,6-diazabicyclo[2.2.2]octane cores (2,6-DABCO) in a five-step one-pot sequence, which is fast, environmentally friendly, operationally simple to manage, and combines step- and atom-economic aspects.

Journal Article↗
PubMed2006

Photoinduced electron transfer in 2-tert-butyl-3-(anthracen-9-yl)-2,3-diazabicyclo[2.2.2]octane.

Intramolecular photoinduced electron transfer from a hydrazine unit to an aromatic group is studied by resonance Raman spectroscopy and electronic absorption spectroscopy. Substituted hydrazine functional groups have played an important role in studies of electron-transfer reactions, photoinduced intramolecular electron transfer, and of mixed valence. A prototypical compound, 2-tert-butyl-3-(anthracen-9-yl)-2,3-diazabicyclo[2.2.2]octane, that has the hydrazine-to-anthracene charge-transfer band in a region of the visible spectrum suitable for detailed resonance Raman spectroscopy is studied in detail. Excitation profiles are obtained, calculated quantitatively by using time-dependent theoretical methods, and interpreted with the assistance of molecular orbital calculations. Excited-state distortions are calculated. The largest distortions occur on the hydrazine unit; the normal mode showing the largest distortion (659 cm(-1), calculated at 665 cm(-1)) involves an out-of-plane C-N-N-C bend consistent with removing an electron from the N-N pi antibonding orbital. Anthracene ring-centered C-C stretches also are enhanced, consistent with populating an antibonding pi orbital centered on the ring. Excellent fits to all of the excitation profiles and to the absorption band are obtained using one set of excited-state potential surfaces.

Journal Article↗
PubMed2000

(-)-Spiro[1-azabicyclo[2.2.2]octane-3,5'-oxazolidin-2'-one], a conformationally restricted analogue of acetylcholine, is a highly selective full agonist at the alpha 7 nicotinic acetylcholine receptor.

Neuronal nicotinic acetylcholine receptors are members of the ligand-gated ion channel receptor superfamily and may play important roles in modulating neurotransmission, cognition, sensory gating, and anxiety. Because of its distribution and abundance in the CNS, the alpha 7 nicotinic receptor is a strong candidate to be involved in some of these functions. In this paper we describe the synthesis and in vitro profile of AR-R17779, (-)-spiro[1-azabicyclo[2.2. 2]octane-3,5'-oxazolidin-2'-one] (4a), a potent full agonist at the rat alpha 7 nicotinic receptor, which is highly selective for the rat alpha 7 nicotinic receptor over the alpha 4 beta 2 subtype. Preliminary SAR of AR-R17779 presented here indicate that there is little scope for modification of this rigid molecule as even minor changes result in significant loss of the alpha 7 nicotinic receptor affinity.

Acetylcholine↗
PubMed1995

Identification of a series of 3-(benzyloxy)-1-azabicyclo[2.2.2]octane human NK1 antagonists.

The synthesis and in vitro and in vivo evaluation of a series of 3-(benzyloxy)-1-azabicyclo-[2.2.2]octane NK1 antagonists are described. While a number of 3,5-disubstituted benzyl ethers afford high affinity, the 3,5-bis(trifluoromethyl)benzyl was found to combine high in vitro affinity with good oral activity. Detailed structure-activity relationship studies in conjunction with data from molecular modeling and mutagenesis work have allowed the construction of a model of the pharmacophore. Specific interactions that have been identified include an interaction between His-197 and one of the rings of the benzhydryl, a lipophilic pocket containing His-265 that the benzyl ether occupies, and a possible hydrogen bond between Gln-165 and the oxygen of the benzyl ether.

Animals↗
PubMed1992

Analogues of the muscarinic agent 2'-methylspiro[1-azabicyclo[2.2.2]octane-3,4'-[1,3]dioxolane]: synthesis and pharmacology.

A number of tetrahydrofuran analogues of 2'-methylspiro[1-azabicyclo[2.2.2]octane-3,4'-[1,3]dioxolane] (1) have been prepared with the aim to obtain information about the relative importance of each of the oxygens in 1 for efficacy and for selectivity. In addition, the dimethyl and desmethyl analogues of 1 were prepared. The new compounds were compared to cis- and trans-1 with regard to their ability to displace (-)-[3H]-3-quinuclidinyl benzilate ((-)-[3H]QNB) from muscarinic receptors in cerebral cortex, heart, parotid gland, and urinary bladder from guinea pigs. Functional studies were made on isolated guinea pig bladder and ileum. The new compounds exhibited both lower affinity and efficacy than cis-1. A conformational study was performed, and the effects of steric and electronic factors on the biological activity of the compounds are discussed.

Animals↗
PubMed1992

The discovery of (2S,3S)-cis-2-(diphenylmethyl)-N-[(2-methoxyphenyl)methyl]-1- azabicyclo[2.2.2]-octan-3-amine as a novel, nonpeptide substance P antagonisst.

We describe the structure-activity relationship development of a series of quinuclidines which culminated in the first potent, selective, nonpeptide substance P (SP) antagonist, (2S,3S)-cis-2-(diphenylmethyl)-N-[(2-methoxy-phenyl)methyl]-1- azabicyclo[2.2.2]octan-3-amine, 3 (CP-96,345). Compound 3 is a potent displacer of [3H]SP binding in human IM-9 cells and blocks SP-induced and capsaicin-induced plasma extravasation, as well as SP-induced salivation in the rat in vivo. This compound may both help to further our understanding of the interactions of small molecules with peptide receptors and serve to evaluate the therapeutic potential of a SP antagonist.

Amino Acid Sequence↗
PubMed1980

Synthesis and analgesic activity of some 5-(4-hydroxyphenyl)-2-azabicyclo[3.2.1]octanes.

A representative series of 5-(4-hydroxyphenyl)-2-azabicyclo[3.2.1]octanes was synthesized and evaluated in vitro, as well as in vivo, as potential analgetic agents. In general, moderate to good activity (19 twice as active as morphine) was observed in the phenylquinone writhing assay (PQW), while only marginal activity was detected by the tail-flick method. Compounds 19 and 18, being the most active in the PQW model, also demonstrated weak binding affinity for the opiate receptors labeled by [3H]naloxone in rat brain homogenates.

Analgesics↗
PubMed1978

Synthesis and analgetic activity of some 5-aryl-2azabicyclo[3.2.1]octanes.

A series of 5-aryl-2-azabicyclo[3.2.1]octanes II has been synthesized and evaluated for analgetic agonist-antagonist activity. These compounds can be regarded as five-membered, conformationally more rigid analogues of the potent agonist-antagonist (-)-5-(3-hydroxyphenyl)-2-methylmorphan (I). Several of these compounds have demonstrated marked analgesic potency comparable to morphine in the mouse writhing assay. Structure-activity correlations, generated by varying N-substitution and O-acetylation of the phenolic function, seem to indicate that optimum activity is associated with an arylethyl side chain attached to the basic nitrogen. Among the most interesting compounds in this series are the phenethyl analogue 31 and its O-acetate 39; the former shows the profile of a well-balanced analgetic-antagonist virtually devoid of physical dependence liability as demonstrated in the rat infusion test.

Analgesics↗