Comparative interaction of 2-hydroxypropyl-β-cyclodextrin and sulfobutylether-β-cyclodextrin with itraconazole: Phase-solubility behavior and stabilization of supersaturated drug solutions

Cyclodextrins can increase the apparent solubility and dissolution rate of poorly water-soluble drug candidates improving their biopharmaceutical performance. The current data assess the ability of hydrophilic cyclodextrins to solubilize compounds via stabilization of supersaturated drug solutions presumably by inhibition of nucleation and arresting crystal growth. To these points, the effects of 2-hydroxypropyl-beta-cyclodextrin (HPbetaCD) and sulfobutylether-beta-cyclodextrin (SBEbetaCD) on equilibrium solubility was assessed via phase-solubility analysis as were the interactions of these excipients on drug solubility under conditions favoring supersaturation. Phase-solubility analysis indicated that different profiles were generated as a function of the cyclodextrin examined and the pH of the complexing medium. When kinetic solubility measurements were completed, the cyclodextrins were found to stabilize concentrations of itraconazole significantly in excess of their equilibrium solubility when supersaturated solutions were formed using the co-solvent/solvent quench approach. These solutions were stable over 240 min falling in concentration at the 24 h time point of the experiment unlike those formed using surfactants and other polymers which demonstrated a rapid decrease in concentration over time. These data suggest that hydrophilic cyclodextrins might be useful formulation adjuncts in supersaturating drug delivery systems.     

The effects of the fibrin-derived peptide Bbeta(15-42) in acute and chronic rodent models of myocardial ischemia-reperfusion

Many compounds have been shown to prevent reperfusion injury in various animal models, although to date, translation into clinic has revealed several obstacles. Therefore, the National Heart, Lung, and Blood Institute convened a working group to discuss reasons for such failure. As a result, the concept of adequately powered, blinded, randomized studies for preclinical development of a compound has been urged. We investigated the effects of a fibrin-derived peptide Bbeta(15-42) in acute and chronic rodent models of ischemia-reperfusion at three different study centers (Universities of Dusseldorf and Vienna, TNO Biomedical Research). A total of 187 animals were used, and the peptide was compared with the free radical scavenger Tempol, CD18 antibody, alpha-C5 antibody, and the golden standard, ischemic preconditioning. We show that Bbeta(15-42) robustly and reproducibly reduced infarct size in all models of ischemia-reperfusion. Moreover, the peptide significantly reduced plasma levels of the cytokines interleukin 1beta, tumor necrosis factor alpha, and interleukin 6. In rodents, Bbeta(15-42) inhibits proinflammatory cytokine release and is cardioprotective during ischemia-reperfusion injury.     

The External Obturator Footprint Is a Usable,Accurate, and Reliable Landmark for Stem Depth in Direct Anterior THA

BackgroundPrevious CT and cadaver studies have suggested that the external obturator footprint might be used as a landmark for stem depth in direct anterior THA. Instructions on where to template this structure with small variability in height have been developed but have not been tested in daily clinical practice.Questions/purposesIn this study we sought to investigate the (1) usability, (2) accuracy, and (3) reliability of the external obturator footprint as a landmark for stem depth in direct anterior THA.MethodsThe distance between the superior border of the external obturator tendon and the shoulder of the stem was measured intraoperatively in all patients (n = 135) who underwent primary THA via a direct anterior approach performed by the senior author between November 2019 and October 2020. The landmark was considered useful when two of thre`e evaluators agreed that the intersection of the vertical line comprised of the lateral wall of the trochanteric fossa and the oblique line formed by the intertrochanteric crest was clearly visible on the preoperative planning radiograph, and when the landmark was furthermore identified with certainty during surgery. Accuracy was defined as the degree of agreement (categorical for thresholds of 2 and 5 mm, the latter representing the threshold for developing unphysiological gait parameters) between the intraoperative distance and radiographic distance as measured on intraoperative fluoroscopy images or postoperative radiographs, which were calibrated based on femoral head sizes in a software program commonly used for templating. Intrarater reliability was defined as the degree of agreement (categorical for thresholds of 1 mm, which we considered an acceptable measurement error) between the ratings of one observer, who measured the radiographic distance on two different occasions separated by a washout period of at least 2 weeks. Interrater reliability was defined as the degree of agreement (categorical for thresholds of 1 mm, which we considered an acceptable measurement error) between the ratings of three observers with varying levels of experience (a fellowship-trained hip surgeon, a hip surgery fellow, and a medical student).ResultsThe landmark was considered useful in 77% (104 of 135) of patients who underwent direct anterior THA based on the observations that the trochanteric fossa was clearly visible on the planning radiograph in 117 patients and that the tendon was identified with certainty during surgery in 118 patients. There was good-to-excellent accuracy (intraclass correlation coefficient 0.75-087), and intrarater reliability (ICC 0.99) and interrater reliability (ICC 0.99) were both excellent.ConclusionThis clinical study showed that the external obturator footprint is a useful, accurate, and reliable landmark for stem depth in direct anterior THA.Clinical RelevanceThe external obturator landmark allows the surgeon to position the stem within a range of the templated depth that is beneath the threshold for the development of unphysiological gait parameters. Although strictly speaking it was found useful in 77% of patients in this study, we found that this percentage of usability can easily be improved to around 90% by providing the radiology lab technician with instructions to correct external rotation of the foot during the taking of the planning radiograph. Future studies could compare the established (in)equality in leg length in patients using the external obturator landmark with computer-assisted surgery.     

Pretargeting of necrotic tumors with biotinylated hypericin using (123)I-labeled avidin: evaluation of a two-step strategy

As an alternative to directly targeting of necrotic tissue using hypericin, we synthesized a conjugate of hypericin to biotin for use in a pretargeting approach. With this conjugate, we explored the possibility of a two-step pretargeting strategy using (123)I-labeled avidin as effector molecule directed against necrotic RIF-1 tumors. Hypericin was conjugated to biotin-ethylenediamine in a straightforward coupling method using n-hydroxysuccinimide and dicyclohexylcarbodiimide. The necrosis avidity of the conjugate was first confirmed in necrotic liver tissue by means of fluorescence microscopy. Using autoradiography imaging and whole body-biodistribution, the accumulation of (123)I-avidin in necrotic tumor tissue was evaluated 24?h after administration and 48?h after pretargeting with hypericin-biotin. Analysis of autoradiography images show a higher accumulation of (123)I-avidin in pretargeted compared to nontargeted tissue. However, absolute accumulation of (123)I-avidin in necrotic tumors was low as shown by biodistribution experiments. Direct injection of hypericin-biotin or biotin-fluorescein did not substantially improve (123)I-avidin accumulation after pretargeting, pointing towards a poor penetration of avidin in necrotic tissue. Our results show the feasibility of a pretargeting technique using a small molecule as targeting agent. However, for a more efficient accumulation of the effector molecule in necrotic tissue, other pretargeting strategies need to be investigated.     

Protein acetylation and aging

Our results suggest the possible benefit of manipulating an intrinsic aging pathway that is independent of nutrition availability, a potential therapeutic route that might be able to bypass shortcomings of calorie restriction.     

Breast cancer cell populations and its changes relation to therapy

This review summarizes the data from published studies that dealt with observation of various bioparameters changes in cancer population dependant on used therapy. Critically evaluating these studies and looking for relations among separate results we are trying to estimate prognostic value of these parameters (likelihood of recurrence, overall survival, ...) and also their value for prediction of tumor response to cytostatic, hormonal or other treatment. The aim is selection of such tumor population characteristics the testing of them would enable better patient stratification in postoperative adjuvant systemic therapy.     

Effect of the unstirred water layer on permeability enhancement by hydrophilic cyclodextrins

Saturated solutions of three test compounds, carbamazepine, griseofulvin and hydrocortisone, were prepared in aqueous buffer (pH 7.4) containing 0, 1, 5 and 10% HPbetaCD. The permeability and flux of the drugs though a PAMPA membrane at different unstirred water layer (UWL) thicknesses was determined. In absence of HPbetaCD, permeability coefficients increased two- to three-fold with decreasing UWL thickness to a certain minimum values of about 40 microm. Addition of HPbetaCD to systems exhibiting larger UWL thicknesses significantly increased compound flux. The effect of HPbetaCD was linked to its association constant (K(1:1)) with the model drugs and decreased with decreasing UWL thickness to a certain minimum value. This suggests that hydrophilic cyclodextrins enhance flux when the UWL resistance significantly contributes to the overall barrier resistance.     

Functional genomics of genes with small open reading frames (sORFs) in S. cerevisiae

Genes with small open reading frames (sORFs; <100 amino acids) represent an untapped source of important biology. sORFs largely escaped analysis because they were difficult to predict computationally and less likely to be targeted by genetic screens. Thus, the substantial number of sORFs and their potential importance have only recently become clear. To investigate sORF function, we undertook the first functional studies of sORFs in any system, using the model eukaryote Saccharomyces cerevisiae. Based on independent experimental approaches and computational analyses, evidence exists for 299 sORFs in the S. cerevisiae genome, representing approximately 5% of the annotated ORFs. We determined that a similar percentage of sORFs are annotated in other eukaryotes, including humans, and 184 of the S. cerevisiae sORFs exhibit similarity with ORFs in other organisms. To investigate sORF function, we constructed a collection of gene-deletion mutants of 140 newly identified sORFs, each of which contains a strain-specific "molecular barcode," bringing the total number of sORF deletion strains to 247. Phenotypic analyses of the new gene-deletion strains identified 22 sORFs required for haploid growth, growth at high temperature, growth in the presence of a nonfermentable carbon source, or growth in the presence of DNA damage and replication-arrest agents. We provide a collection of sORF deletion strains that can be integrated into the existing deletion collection as a resource for the yeast community for elucidating gene function. Moreover, our analyses of the S. cerevisiae sORFs establish that sORFs are conserved across eukaryotes and have important biological functions.     

Safe implementation of robotic-assisted minimally invasive direct coronary artery bypass: application of learning curves and cumulative sum analysis

BackgroundLearning curves are inevitably encountered when first implementing an innovative and complex surgical technique. Nevertheless, a cluster of failures or complications should be detected early, but not deter learning, to ensure safe implementation. Here, we aimed to examine the presence and impact of learning curves on outcome after robotic-assisted minimally invasive direct coronary artery bypass (RA-MIDCAB).MethodsA retrospective analysis of the first 300 RA-MIDCAB surgeries between July 2015 and December 2020 was performed. Learning curves were obtained via logarithmic regression for surgical time. Cumulative sum (CUSUM) analysis was performed for (I) major complications including MI, stroke, repeat revascularization, and mortality, and (II) other complications, including prolonged ventilation, pneumonia, pleura puncture, lung herniation, pericarditis, pleuritis, arrhythmia, wound complications, and delirium. Expected and unacceptable rates were set at 12% and 20%, respectively, for major complications, and at 40% and 60% for other complications, based on historical data in conventional coronary artery bypass grafting (CABG).ResultsDemographic characteristics did not differ between terciles, except for more smokers in the first tercile, and less hypercholesterolemia and more complex procedures in the third tercile. The mean surgical time for all operations was 258±81 minutes, ranging from 127 to 821 minutes. A learning curve was only observed in the first tercile. Subgroup analysis revealed that this learning curve was only observed for procedures consisting of single internal mammary artery (SIMA) with 1 or 2 distal anastomoses but not with bilateral internal mammary arteries (BIMA) or more than 2 distal anastomoses. CUSUM analysis showed that the cumulative rate of major and other complications never crossed the lines for unacceptable rates. Rather, the lower 95% confidence boundary was crossed after 50 cases, indicating improvement in safety.ConclusionsThese results suggest that integration of RA-MIDCAB in the surgical landscape can be safely achieved and complication rates can quickly be reduced below those expected in traditional CABG. Collective experience plays a key role in overcoming the learning curve when more complex procedures and cases are introduced.