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- Acosta Ruiz, Vanessa, 1987-, et al.
(författare)
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Microwave ablation of 105 T1 renal tumors : technique efficacy with a mean follow-up of two years
- 2024
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Ingår i: Acta Radiologica. - : Sage Publications. - 0284-1851 .- 1600-0455. ; 65:3, s. 294-301
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThermal ablation (TA) with radiofrequency (RFA) or cryoablation (CA) are established treatments for small renal masses (≤4 cm). Microwave ablation (MWA) has several potential benefits (decreased ablation time, less susceptibility to heat-sink, higher lesion temperatures than RFA) but is still considered experimental considering the available small-sample studies with short follow-up.PurposeTo evaluate technique efficacy and complications of our initial experience of renal tumors treated using percutaneous MWA with a curative intent.Material and MethodsA total of 105 renal tumors (in 93 patients) were treated between April 2014 and August 2017. MWA was performed percutaneously with computed tomography (CT) guidance under conscious sedation (n=82) or full anesthesia. Patients were followed with contrast-enhanced CT scans at six months and yearly thereafter for a minimum of five years. The mean follow-up time was 2.1 years. The percentage of tumors completely ablated in a single session (primary efficacy rate) and those successfully treated after repeat ablation (secondary efficacy rate) were recorded. Patient and tumor characteristics as well as complications were collected retrospectively.ResultsThe median patient age was 70 years and median tumor size was 25 mm. Primary efficacy rate was 96.2% (101/105 tumors). After including two residual tumors for a second ablation session, secondary efficacy was 97.1% (102/105). Periprocedural complications were found in 5.2% (5/95) sessions: four Clavien-Dindo I and one Clavien-Dindo IIIa. One postprocedural Clavien-Dindo II complication was found.ConclusionMWA has high efficacy rates and few complications compared to other TA methods at a mean follow-up of two years.
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| 2. |
- Acosta Ruiz, Vanessa, et al.
(författare)
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Periprocedural outcome after laparoscopic partial nephrectomy versus radiofrequency ablation for T1 renal tumors : A modified R.E.N.A.L nephrometry score adjusted comparison
- 2019
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Ingår i: Acta Radiologica. - : Sage Publications. - 0284-1851 .- 1600-0455. ; 60:2, s. 260-268
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Tidskriftsartikel (refereegranskat)abstract
- Background: Comparable oncological outcomes have been seen after surgical nephrectomy and thermal ablation of renal tumors recently. However, periprocedural outcome needs to be assessed for aiding treatment decision.Purpose: To compare efficacy rates and periprocedural outcome (technical success, session time, hospitalization time, and complications) after renal tumor treatment with laparoscopic partial nephrectomy (LPN) or radiofrequency ablation (RFA).Material and Methods: The initial experience with 49 (treated with LPN) and 84 (treated with RFA) consecutive patients for a single renal tumor (diameter ≤ 5 cm, limited to the kidney) during 2007-2014 was evaluated. Patient and tumor characteristics, efficacy rates, and periprocedural outcome were collected retrospectively. The stratified Mantel Haenzel and Van Elteren tests, adjusted for tumor complexity (with the modified R.E.N.A.L nephrometry score [m-RNS]), were used to assess differences in treatment outcomes.Results: Primary efficacy rate was 98% for LPN and 85.7% for RFA; secondary efficacy rate was 93.9% for LPN and 95.2% for RFA; and technical success rate was 87.8% for LPN and 100% for RFA. Median session (m-RNS adjusted P < 0.001; LPN 215 min, RFA 137 min) and median hospitalization time were longer after LPN (m-RNS adjusted P < 0.001; LPN 5 days, RFA 2 days). Side effects were uncommon (LPN 2%, RFA 4.8%). Complications were more frequent after LPN (m-RNS adjusted P < 0.001; LPN 42.9%, RFA 10.7%).Conclusion: Both methods achieved equivalent secondary efficacy rates. RFA included several treatment sessions, but session and hospitalization times were shorter, and complications were less frequent than for LPN. The differences remained after adjustment for renal tumor complexity.
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| 3. |
- Acosta Ruiz, Vanessa, et al.
(författare)
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Predictive factors for complete renal tumor ablation using RFA
- 2016
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Ingår i: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 57:7, s. 886-893
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Radiofrequency ablation (RFA) can be used to treat renal masses in patients where surgery is preferably avoided. As tumor size and location can affect ablation results, procedural planning needs to identify these factors to limit treatment to a single session and increase ablation success.PURPOSE: To identify factors that may affect the primary efficacy of complete renal tumor ablation with radiofrequency after a single session.MATERIAL AND METHODS: Percutaneous RFA (using an impedance based system) was performed using computed tomography (CT) guidance. Fifty-two renal tumors (in 44 patients) were retrospectively studied (median follow-up, 7 months). Data collection included patient demographics, tumor data (modified Renal Nephrometry Score, histopathological diagnosis), RFA treatment data (electrode placement), and follow-up results (tumor relapse). Data were analyzed through generalized estimating equations.RESULTS: Primary efficacy rate was 83%. Predictors for complete ablation were optimal electrode placement (P = 0.002, OR = 16.67) and increasing distance to the collecting system (P = 0.02, OR = 1.18). Tumor size was not a predictor for complete ablation (median size, 24 mm; P = 0.069, OR = 0.47), but all tumors ≤2 cm were completely ablated. All papillary tumors and oncocytomas were completely ablated in a single session; the most common incompletely ablated tumor type was clear cell carcinoma (6 of 9).CONCLUSION: Optimal electrode placement and a long distance from the collecting system are associated with an increased primary efficacy of renal tumor RFA. These variables need to be considered to increase primary ablation success. Further studies are needed to evaluate the effect of RFA on histopathologically different renal tumors.
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| 5. |
- Beigi, Farideh, et al.
(författare)
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Immobilized liposome and biomembrane partitioning chromatography of drugs for prediction of drug transport
- 1998
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Ingår i: International Journal of Pharmaceutics. - 0378-5173 .- 1873-3476. ; 164:1-2, s. 129-137
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Tidskriftsartikel (refereegranskat)abstract
- Drug partitioning into lipid bilayers was studied by chromatography on liposomes and biomembranes immobilized in gel beads by freeze–thawing. The drug retention volume was expressed as a capacity factor, Ks, normalized with respect to the amount of immobilized phospholipid. Log Ks values for positively charged drugs on brain phosphatidylserine (PS)/egg phosphatidylcholine (PC) liposomes decreased as the ionic strength was increased, increased as the PS:PC ratio or the pH was increased and varied linearly with the temperature. Log Ks values for beta-blockers, phenothiazines and benzodiazepines on egg phospholipid (EPL) liposomes correlated well with corresponding values on red cell membrane lipid liposomes (r2=0.96), and on human red cell membrane vesicles containing transmembrane proteins (r2=0.96). A fair correlation was observed between the values on EPL liposomes and those on native membranes of adsorbed red cells (r2=0.86). Compared to the data obtained with liposomes, the retentions of hydrophilic drugs became larger and the range of log Ks values more narrow on the vesicles and the membranes, which expose hydrophilic protein surfaces and oligosaccharides. Lower correlations were observed between drug retention on EPL liposomes and egg PC liposomes; and between retention on liposomes (or vesicles) and immobilized artificial membrane (IAM) monolayers of PC analogues. Absorption of orally administered drugs in humans (literature data) was nearly complete for drugs of log Ks values in the interval 1.2–2.5 on vesicles. Both vesicles and liposomes can thus be used for chromatographic analysis of drug–membrane interaction and prediction of drug absorption.
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| 8. |
- Brekkan, Ari, et al.
(författare)
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A Population Pharmacokinetic-Pharmacodynamic Model of Pegfilgrastim
- 2018
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Ingår i: AAPS Journal. - : SPRINGER. - 1550-7416. ; 20:5
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Tidskriftsartikel (refereegranskat)abstract
- Neutropenia and febrile neutropenia (FN) are serious side effects of cytotoxic chemotherapy which may be alleviated with the administration of recombinant granulocyte colony-stimulating factor (GCSF) derivatives, such as pegfilgrastim (PG) which increases absolute neutrophil count (ANC). In this work, a population pharmacokinetic-pharmacodynamic (PKPD) model was developed based on data obtained from healthy volunteers receiving multiple administrations of PG. The developed model was a bidirectional PKPD model, where PG stimulated the proliferation, maturation, and margination of neutrophils and where circulating neutrophils in turn increased the elimination of PG. Simulations from the developed model show disproportionate changes in response with changes in dose. A dose increase of 10% from the 6 mg therapeutic dose taken as a reference leads to area under the curve (AUC) increases of similar to 50 and similar to 5% for PK and PD, respectively. A full random effects covariate model showed that little of the parameter variability could be explained by sex, age, body size, and race. As a consequence, little of the secondary parameter variability (C-max and AUC of PG and ANC) could be explained by these covariates.
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| 10. |
- Brekkan, Ari, et al.
(författare)
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Characterization of anti-drug antibody dynamics using a bivariate mixed hidden-markov model by nonlinear-mixed effects approach
- 2024
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Ingår i: Journal of Pharmacokinetics and Pharmacodynamics. - : Springer. - 1567-567X .- 1573-8744. ; 51:1, s. 65-75
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Tidskriftsartikel (refereegranskat)abstract
- Biological therapies may act as immunogenic triggers leading to the formation of anti-drug antibodies (ADAs). Population pharmacokinetic (PK) models can be used to characterize the relationship between ADA and drug disposition but often rely on the ADA bioassay results, which may not be sufficiently sensitive to inform on this characterization.In this work, a methodology that could help to further elucidate the underlying ADA production and impact on the drug disposition was explored. A mixed hidden-Markov model (MHMM) was developed to characterize the underlying (hidden) formation of ADA against the biologic, using certolizumab pegol (CZP), as a test drug. CZP is a PEGylated Fc free TNF-inhibitor used in the treatment of rheumatoid arthritis and other chronic inflammatory diseases.The bivariate MHMM used information from plasma drug concentrations and ADA measurements, from six clinical studies (n = 845), that were correlated through a bivariate Gaussian function to infer about two hidden states; production and no-production of ADA influencing PK. Estimation of inter-individual variability was not supported in this case. Parameters associated with the observed part of the model were reasonably well estimated while parameters associated with the hidden part were less precise. Individual state sequences obtained using a Viterbi algorithm suggested that the model was able to determine the start of ADA production for each individual, being a more assay-independent methodology than traditional population PK. The model serves as a basis for identification of covariates influencing the ADA formation, and thus has the potential to identify aspects that minimize its impact on PK and/or efficacy.
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