1,720,965 research outputs found
Pharmacokinetics of efavirenz (EFV) alone and in combination therapy with nelfinavir (NFV) in HIV-1 infected patients.
No full textComparison of the plasma pharmacokinetics of lamivudine during twice and once daily administration in patients with HIV
No full textObjective: To compare the plasma pharmacokinetics of lamivudine 150mg twice daily and 300mg once daily in patients with HIV-1 infection. Design: Nonblind, sequential, pharmacokinetic study. Participants: 13 patients with HIV-1 infection (median age 36 years). Methods: Patients were tested during twice daily and then once daily regimens of lamivudine. In both regimens, the total daily dose of lamivudine was identical (300 mg/day). Blood samples for pharmacokinetic analysis were taken over a 12-hour period after ≥7 days of twice daily administration, and again over a 24-hour period after 7 days of once daily administration. Results: 12 patients completed the study. Lamivudine pharmacokinetic parameters (mean±SD) after administration of 150mg twice daily were: peak plasma concentration (Cmax) 2077±816 μg/L; trough plasma concentration (Cmin) 332±219 μg/L; elimination half-life (t1/2β) 6.1±1.9h; time to Cmax(tmax) 1.6±0.7h; average concentration over the dosage interval (Cav) 711±269 μg/L; and area under the concentration-time curve (AUC) over 2 dosage intervals (24h) 17 085±6464 μg · h/L. Corresponding values after administration of 300mg once daily were: Cmax 3461±854 μg/L; Cmin 146±87 μg/L; t1/2β 7.9±3.4h; tmax 2.2±1.3h; Cav 705±177 μg/L; and AUC over 1 dosage interval (24h) 16 644±4150 μg · h/L. Statistical analysis showed a significant difference (p<0.05) between the 2 schedules for Cmax and Cmin values, whereas no significant differences emerged for the other parameters. Conclusions: Once daily lamivudine leads to a similar exposure in plasma as twice daily administration of the same total daily dose. Since once daily administration may result in improved compliance, these results provide the pharmacokinetic basis for using lamivudine in a once daily regimen. Randomised clinical studies are needed to confirm this pharmacokinetic finding
Pharmacokinetic evaluation of oral levofloxacin in human immunodeficiency virus-infected subjects receiving concomitant antiretroviral therapy
No full textEvaluation of two buflomedil tablet formulations in patients with atherosclerotic disease.
No full textThe bioequivalence of a 600-mg methocel tablet containing buflomedil hydrochloride in sustained-release form was determined relative to a 300-mg CAP/carbovax-coated tablet of buflomedil hydrochloride in immediate-release form. The tablets were given to 20 patients in a double-blind placebo- controlled clinical study with cross-over between the administration plans. The 300-mg tablets were given b.i.d., at 8 a.m. and 8 p.m. while the 600-mg tablets were taken once a day at 8 a.m. (+placebo at 8 p.m.). Plasma samples were collected at appropriate times up to 24 h after administration and were analysed for buflomedil with a validated high-performance liquid chromatographic procedure. Results showed an overall significant mean difference in absorption rate between the two formulations. The mean t(max) (5.5 ± 3.5 h) for the 600-mg tablet was longer (P<0.001) than the t(max) value (1.8 ± 0.8 h) seen after administration of the first 300-mg tablet. Analysis of AUC((O-∞)) values indicated that the sustained-release preparation (32.1 ± 20.7 μg/ml h) was not significantly different from the 300-mg tablet b.i.d. (28.7 ± 16.0 μg/ml h). Furthermore, it was seen that single administration of a 600-mg sustained-release tablet of buflomedil hydrochloride delivered the same amount of total drug as a 300-mg tablet given twice a day
Pharmacokinetic behavior of Rituximab: a study of different schedules of administration for heterogeneous clinical settings.
No full textThis study was designed to report the pharmacokinetic
behavior of Rituximab in patients affected with different diseases
and treated with different schedules of administration. A low tumor
burden was a common feature of all patients (N = 48) included in our
study, whereas the timing of Rituximab administration varied from
weekly (groups 1, 2, 3) to monthly (group 4). Group 1 included patients
with follicular lymphoma treated with 4 weekly doses of
Rituximab after first-line chemotherapy with CHOP. At the start of
Rituximab, patients were in partial or complete clinical response but
showed persistence of disease at molecular level (bcl-2–positive) in
bone marrow and/or peripheral blood. Patients in group 2 had autoimmune
disorders and Rituximab was given to act on B-cells, interfering
with their production of autoantibodies. In patients with amyloidosis
(group 3), Rituximab was given to kill progenitor B-cells of the small
clone terminating in amyloid-producing plasma cells. In groups 2 and
3, the target of monoclonal antibody was a population of small B
cells, which make an intrinsic feature of the diseases. Group 4 included
patients with relapsed or refractory follicular and mantle cell
lymphoma who underwent a salvage program of immunochemotherapy,
purging in vivo and autotransplant: the first of the six planned
doses of Rituximab was administered after a debulking phase with a
third-generation regimen, such as VACOP-B. An enzyme-linked immunoassay
(ELISA) developed and validated in our laboratory was
used for the pharmacokinetic study. Rituximab disposition was characterized
by a 2-exponential decay, with a long elimination half-life
of approximately 3 weeks (range, 248–859 hours). The total systemic
clearance ranged between 3.1 and 11.9 mL/hr/m2. After 4 weekly infusions,
Rituximab concentration was ;2.5 mg/mL, which is approximately
85% of the steady-state level. Steady-state plasma concentrations
of Rituximab were reached after 6 to 8 weekly infusions. The adopted
pharmacokinetic model (2-compartment open model) seems to provide
the best fit of Rituximab disposition both during and after treatment,
even when different schedules of drug administration are used. Because
several studies reported an association between response and
serum Rituximab concentrations, a treatment based on a pharmacokinetic
model may be useful for predicting the desired drug
concentration
Pharmacokinetic Behavior of Rituximab: A Study of Different Schedules of Administration for Heterogeneous Clinical Settings
No full textThis study was designed to report the pharmacokinetic behavior of Rituximab in patients affected with different diseases and treated with different schedules of administration. A low tumor burden was a common feature of all patients (N=48) included in our study, whereas the timing of Rituximab administration varied from weekly (groups 1, 2, 3) to monthly (group 4). Group 1 included patients with follicular lymphoma treated with 4 weekly doses of Rituximab after first-line chemotherapy with CHOP. At the start of Rituximab, patients were in partial or complete clinical response but showed persistence of disease at molecular level (bcl-2-positive) in bone marrow and/or peripheral blood. Patients in group 2 had autoimmune disorders and Rituximab was given to act on B-cells, interfering with their production of autoantibodies. In patients with amyloidosis (group 3), Rituximab was given to kill progenitor B-cells of the small clone terminating in amyloid-producing plasma cells. In groups 2 and 3, the target of monoclonal antibody was a population of small B cells, which make an intrinsic feature of the diseases. Group 4 included patients with relapsed or refractory follicular and mantle cell lymphoma who underwent a salvage program of immunochemotherapy, purging in vivo and autotransplant: the first of the six planned doses of Rituximab was administered after a debulking phase with a third-generation regimen, such as VACOP-B. An enzyme-linked immunoassay (ELISA) developed and validated in our laboratory was used for the pharmacokinetic study. Rituximab disposition was characterized by a 2-exponential decay, with a long elimination half-life of approximately 3 weeks (range, 248-859 hours). The total systemic clearance ranged between 3.1 and 11.9 mL/hr/m. After 4 weekly infusions, Rituximab concentration was approximately 2.5 microg/mL, which is approximately 85% of the steady-state level. Steady-state plasma concentrations of Rituximab were reached after 6 to 8 weekly infusions. The adopted pharmacokinetic model (2-compartment open model) seems to provide the best fit of Rituximab disposition both during and after treatment, even when different schedules of drug administration are used. Because several studies reported an association between response and serum Rituximab concentrations, a treatment based on a pharmacokinetic model may be useful for predicting the desired drug concentration
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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