23 research outputs found

    Ototoxic reactions of quinine in healthy persons and patients with Plasmodium falciparum infection

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    Audiometric changes following quinine administration were studied in healthy Caucasian subjects and patients suffering from falciparum malaria disease. Quinine-dihydrochloride was administered intravenously as a single dose of 300 mg to 12 healthy subjects and as multiple doses of 600 mg in 4 h every 8 h in 10 Plasmodium falciparum malaria patients. The hearing function was monitored by conventional and high frequency audiometry. In nine healthy subjects hearing loss was documented at 2-4 h after infusion of Quinine-dihydrochloride at a mean maximal plasma quinine concentration of only 2 mg/l. In one healthy subject a persistent loss occurred of 20 dB at 14 kHz in one ear. In all malaria patients severe hearing losses and adverse effects related to ototoxicity were documented, but all the audiograms had returned to normal after 1 week and side effects disappeared. This study has shown that ototoxicity induced by quinine is almost completely reversible in healthy volunteers and in malaria patient

    Role of dipolar and exchange interactions in the positions and widths of EPR transitions for the single-molecule magnets Fe8 and Mn12

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    We examine quantitatively the temperature dependence of the linewidths and line shifts in electron paramagnetic resonance experiments on single crystals of the single-molecule magnets Fe8_8 and Mn12_{12}, at fixed frequency, with an applied magnetic field along the easy axis. We include inter-molecular spin-spin interactions (dipolar and exchange) and distributions in both the uniaxial anisotropy parameter DD and the Land\'{e} gg-factor. The temperature dependence of the linewidths and the line shifts are mainly caused by the spin-spin interactions. For Fe8_8 and Mn12_{12}, the temperature dependence of the calculated line shifts and linewidths agrees well with the trends of the experimental data. The linewidths for Fe8_8 reveal a stronger temperature dependence than those for Mn12_{12}, because for Mn12_{12} a much wider distribution in DD overshadows the temperature dependence of the spin-spin interactions. For Fe8_8, the line-shift analysis suggests two competing interactions: a weak ferromagnetic exchange coupling between neighboring molecules and a longer-ranged dipolar interaction. This result could have implications for ordering in Fe8_8 at low temperatures.Comment: published versio

    Semiconductive and Photoconductive Properties of the Single Molecule Magnets Mn12_{12}-Acetate and Fe8_8Br8_8

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    Resistivity measurements are reported for single crystals of Mn12_{12}-Acetate and Fe8_8Br8_8. Both materials exhibit a semiconductor-like, thermally activated behavior over the 200-300 K range. The activation energy, EaE_a, obtained for Mn12_{12}-Acetate was 0.37 ±\pm 0.05 eV, which is to be contrasted with the value of 0.55 eV deduced from the earlier reported absorption edge measurements and the range of 0.3-1 eV from intramolecular density of states calculations, assuming 2Ea2E_a= EgE_g, the optical band gap. For Fe8_8Br8_8, EaE_a was measured as 0.73 ±\pm 0.1 eV, and is discussed in light of the available approximate band structure calculations. Some plausible pathways are indicated based on the crystal structures of both lattices. For Mn12_{12}-Acetate, we also measured photoconductivity in the visible range; the conductivity increased by a factor of about eight on increasing the photon energy from 632.8 nm (red) to 488 nm (blue). X-ray irradiation increased the resistivity, but EaE_a was insensitive to exposure.Comment: 7 pages, 8 figure

    Non-AIDS defining cancers in the D:A:D Study-time trends and predictors of survival : a cohort study

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    BACKGROUND:Non-AIDS defining cancers (NADC) are an important cause of morbidity and mortality in HIV-positive individuals. Using data from a large international cohort of HIV-positive individuals, we described the incidence of NADC from 2004-2010, and described subsequent mortality and predictors of these.METHODS:Individuals were followed from 1st January 2004/enrolment in study, until the earliest of a new NADC, 1st February 2010, death or six months after the patient's last visit. Incidence rates were estimated for each year of follow-up, overall and stratified by gender, age and mode of HIV acquisition. Cumulative risk of mortality following NADC diagnosis was summarised using Kaplan-Meier methods, with follow-up for these analyses from the date of NADC diagnosis until the patient's death, 1st February 2010 or 6 months after the patient's last visit. Factors associated with mortality following NADC diagnosis were identified using multivariable Cox proportional hazards regression.RESULTS:Over 176,775 person-years (PY), 880 (2.1%) patients developed a new NADC (incidence: 4.98/1000PY [95% confidence interval 4.65, 5.31]). Over a third of these patients (327, 37.2%) had died by 1st February 2010. Time trends for lung cancer, anal cancer and Hodgkin's lymphoma were broadly consistent. Kaplan-Meier cumulative mortality estimates at 1, 3 and 5 years after NADC diagnosis were 28.2% [95% CI 25.1-31.2], 42.0% [38.2-45.8] and 47.3% [42.4-52.2], respectively. Significant predictors of poorer survival after diagnosis of NADC were lung cancer (compared to other cancer types), male gender, non-white ethnicity, and smoking status. Later year of diagnosis and higher CD4 count at NADC diagnosis were associated with improved survival. The incidence of NADC remained stable over the period 2004-2010 in this large observational cohort.CONCLUSIONS:The prognosis after diagnosis of NADC, in particular lung cancer and disseminated cancer, is poor but has improved somewhat over time. Modifiable risk factors, such as smoking and low CD4 counts, were associated with mortality following a diagnosis of NADC

    Cytokine responses in pneumocystis carinii pneumonia

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    Item does not contain fulltextK.U. Nijmegen, 2 december 1996Promotores : Pont, J.J.H.H.M. de, Grip, W.J. de Co-promotores : Meer, J.W.M. van der, Sauerwein, R.W., Beckers, P.J.A

    Cytokine responses in Pneumocystis carinii pneumonia

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    Contains fulltext : mmubn000001_234349603.pdf (publisher's version ) (Open Access)Promotores : J. van der Meer, R. Sauerwein en P. Beckers100 p
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