Rate constants have been determined by steady-state EPR spectroscopy experiments for hydrogen-atom abstraction by Bu'O' from a variety of esters. The values, which range over two orders of magnitude (5 x 10(3)-5 x 10(5) dm(3) mol(-1) s(-1) at ca. 300 K) are significantly lower than those for related ketones and ethers and reflect, at least in part, the importance of the appropriate C-H bond dissociation energies and the stabilization of carbonyl-conjugated radicals, The relative lack of reactivity of C-H bonds in unsubstituted five-membered rings is believed to reflect ring-strain in the derived radicals;possible stereoelectronic effects are discussed.

Principles and practice of infectious diseases, handbook of antimicrobial therapy, 1992 , Principles and practice of infectious diseases, handbook of antimicrobial therapy, 1992 , کتابخانه دیجیتالی دانشگاه علوم پزشکی و خدمات درمانی شهید بهشتی

Continuous-flow EPR studies of the reaction between Ce(IV) and the peroxymonosulphate anion HOOSO3- at low pH enable the isotropic EPR spectrum of SO5.- to be characterized, and provide kinetic information on the formation and reaction of this radical. Alkylperoxyl radicals (RO2.) detected when the reaction is carried out in the presence of alkenes (e.g. methyl methacrylate) are shown to arise from reactions of SO4.- (derived from self-reaction of SO5.-) with the alkene, and subsequent addition of oxygen (also formed from SO5.-).

The kinetics of reactions of t-butylperoxyl radicals in aqueous solution have been measured using electron paramagnetic resonance, ultraviolet absorption spectroscopy and gas chromatography. The rate constants for the overall self-reaction, the separate terminating and non-terminating reactions are very similar to those observed in non-polar solvents and the gas phase. The t-butoxyl radicals, formed by the non-terminating reaction, can either undergo scission, which leads to methylperoxyl radicals, or react with further t-butyl hydroperoxide to regenerate t-butylperoxyl radicals. The cross-termination reaction between methylperoxyl and t-butylperoxyl radicals is an important route in the overall termination sequence. The propagation reaction occurs significantly only at high concentrations of t-butyl hydroperoxide, ([ButOOH] > 0.3 mol dm–3) and its rate constant is much lower than that in non-polar solutions.

ChemInformVolume 19, Issue 44 Preparative Organic Chemistry ChemInform Abstract: A Kinetic ESR Study of the Self-Reactions of Some Aromatic and Aliphatic Sulfonyl Radicals and Aromatic Sulfinyl Radicals J. E. BENNETT, J. E. BENNETT Dep. Chem., Univ. York, Heslington, York YO10 5DD, UKSearch for more papers by this authorG. BRUNTON, G. BRUNTON Dep. Chem., Univ. York, Heslington, York YO10 5DD, UKSearch for more papers by this authorB. C. GILBERT, B. C. GILBERT Dep. Chem., Univ. York, Heslington, York YO10 5DD, UKSearch for more papers by this authorP. E. WHITTALL, P. E. WHITTALL Dep. Chem., Univ. York, Heslington, York YO10 5DD, UKSearch for more papers by this author J. E. BENNETT, J. E. BENNETT Dep. Chem., Univ. York, Heslington, York YO10 5DD, UKSearch for more papers by this authorG. BRUNTON, G. BRUNTON Dep. Chem., Univ. York, Heslington, York YO10 5DD, UKSearch for more papers by this authorB. C. GILBERT, B. C. GILBERT Dep. Chem., Univ. York, Heslington, York YO10 5DD, UKSearch for more papers by this authorP. E. WHITTALL, P. E. WHITTALL Dep. Chem., Univ. York, Heslington, York YO10 5DD, UKSearch for more papers by this author First published: November 1, 1988 https://doi.org/10.1002/chin.198844084Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume19, Issue44November 1, 1988 RelatedInformation

A variety of aromatic and aliphatic sulphonyl radicals (RSO2˙) have been found to undergo diffusion-controlled self-reaction in solution (with 2kt typically ca. 109 dm3 mol–1 s–1); reaction proceeds somewhat slower for some sterically hindered arenesulphonyl radicals (ArSO2˙) and for some arenesulphinyl analogues (ArSO˙). The observation of curved Arrhenius plots for some ArSO2˙ radicals, as well as the detection of ArSO˙ from sulphonyl precursors under steady-state conditions, is attributed to the thermal decomposition of an unstable intermediate formed by dimerisation (sulphur-to-oxygen) of ArSO2˙. A thermodynamic and kinetic analysis is presented.

The clinical course and response to therapy of 27 patients with cryptococcosis and the acquired immunodeficiency syndrome were reviewed. Cryptococcosis was the initial manifestation of the syndrome in 7 patients, and the initial opportunistic infection in an additional 7. Meningitis was the commonest clinical feature (18 patients). Blood cultures and serum cryptococcal antigen were frequently positive. In patients with meningitis, leukocyte count, protein level, and glucose level in cerebrospinal fluid were frequently normal; cerebrospinal fluid India ink test (82%), culture (100%), and cryptococcal antigen (100%) were usually positive. Only 10 of 24 patients had no evidence of clinical activity of cryptococcal infection after completion of therapy; 6 of these 10 had relapses shown by clinical findings or at autopsy. Standard courses of amphotericin B alone or combined with flucytosine were ineffective. Cryptococcosis in patients with the syndrome is a debilitating disease that does not respond to conventional therapy; earlier diagnosis or long-term suppressive therapy may improve the prognosis.

Patients with the hyperimmunoglobulin E-recurrent infection (Job's) syndrome, which is characterized by an elevated immunoglobulin E level, recurrent staphylococcal infections, and an abnormality of neutrophil chemotaxis, have been reported to have visceral Candida infections in addition to their more frequent pyogenic infections. We report a patient with Job's syndrome who presented with massive hematemesis secondary to esophageal cryptococcosis. A thorough evaluation for an occult neoplasm or extraesophageal cryptococcosis was negative. The patient received a 6-wk course of amphotericin B (970 mg) and 5-fluorocytosine with complete radiographic and endoscopic resolution of the lesion. He is doing well 18 mo after therapy. The patient was not anergic, and his response to T-cell mitogens, helper-to-suppressor T-cell ratio, total number of T cells, and immunoglobulin-producing capability were all normal. This case is unusual in that it is the first documentation of a cryptococcoma of the esophagus and underscores the importance of culturing abnormal specimens for unsuspected pathogens in unusual clinical circumstances.

Chemischer InformationsdienstVolume 15, Issue 3 Physical Organic Chemistry ChemInform Abstract: REACTIVITY AND STRUCTURE OF N-PHENYL-1-NAPHTHYLAMINES AND RELATED COMPOUNDS. PART 2. UNPAIRED ELECTRON DISTRIBUTION IN 1-NAPHTHYL PHENYL NITROXIDES J. E. BENNETT, J. E. BENNETTSearch for more papers by this authorG. BRUNTON, G. BRUNTONSearch for more papers by this authorA. R. FORRESTER, A. R. FORRESTERSearch for more papers by this authorJ. D. FULLERTON, J. D. FULLERTONSearch for more papers by this author J. E. BENNETT, J. E. BENNETTSearch for more papers by this authorG. BRUNTON, G. BRUNTONSearch for more papers by this authorA. R. FORRESTER, A. R. FORRESTERSearch for more papers by this authorJ. D. FULLERTON, J. D. FULLERTONSearch for more papers by this author First published: January 17, 1984 https://doi.org/10.1002/chin.198403045Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume15, Issue3January 17, 1984 RelatedInformation

AbstractIm Gegensatz zum Verhalten von Diphenylamin ergibt die Titelreaktion der Antioxidantien (I) mit photochemisch oder thermisch erzeugten 1‐Methyl‐cyclohexylperoxylradikalen bei 253‐338 K nur geringen Nitroxidanteil am Produktgemisch.

Chemischer InformationsdienstVolume 15, Issue 3 Physical Organic Chemistry ChemInform Abstract: REACTIVITY AND STRUCTURE OF N-PHENYL-1-NAPHTHYLAMINES AND RELATED COMPOUNDS. PART 2. UNPAIRED ELECTRON DISTRIBUTION IN 1-NAPHTHYL PHENYL NITROXIDES J. E. BENNETT, J. E. BENNETTSearch for more papers by this authorG. BRUNTON, G. BRUNTONSearch for more papers by this authorA. R. FORRESTER, A. R. FORRESTERSearch for more papers by this authorJ. D. FULLERTON, J. D. FULLERTONSearch for more papers by this author J. E. BENNETT, J. E. BENNETTSearch for more papers by this authorG. BRUNTON, G. BRUNTONSearch for more papers by this authorA. R. FORRESTER, A. R. FORRESTERSearch for more papers by this authorJ. D. FULLERTON, J. D. FULLERTONSearch for more papers by this author First published: January 17, 1984 https://doi.org/10.1002/chin.198403045Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume15, Issue3January 17, 1984 RelatedInformation

Rate constants for the reaction of a series of N-phenylnaphth-1-ylamines and some related nitroxides and hydroxylamines with t-alkylperoxyl radicals have been measured using kinetic e.s.r. spectrometry and activation energies and A factors have been derived. The stoicheiometry of the reaction (peroxyl radical to N-phenylnaphth-1-ylamine) has been shown to be ca. 2 in all cases.

A gas chromatographic-mass spectrometric method for detecting 5-fluorouracil (5-FU) in serum at concentrations as low as 10 ng/ml was used to determine to what extent 5-FU was present in the serum of patients taking oral 5-fluorocytosine (5-FC). Preliminary studies in two patients and two healthy volunteers given an initial 2-g oral dose of 5-FC demonstrated sustained serum 5-FU levels (>100 ng/ml) during the 5 h after ingestion of drug. Pharmaceutical preparations of 5-FC used in these studies were shown to be insignificantly contaminated with 5-FU (<0.03%), suggesting in vivo conversion of 5-FC to 5-FU had occurred. Serum samples from seven patients with cryptococcal meningitis treated with amphotericin B and 5-FC were examined for 5-FU. Five of these patients had experienced hematological or other toxicity attributed to 5-FC at some time during the course of therapy. Of 41 serum samples, 20 were observed to have 5-FU levels greater than 1,000 ng/ml in the range observed with cancer chemotherapeutic doses of 5-FU known to be associated with hematological toxicity. It is concluded that conversion of 5-FC to 5-FU occurs in humans and furthermore that 5-FU may account for some of the toxicity observed with 5-FC.