Variations of microstructure, mineral density and tissue elasticity in B6/C3H mice

200-MHz scanning acoustic microscopy (SAM) and synchrotron radiation μCT (SR-μCT) were used to assess microstructural parameters, acoustic impedance Z and tissue degree of mineralization of bone (DMB) in site-matched regions of interest in femoral bone of two inbred strains. Transverse femoral sections taken from 5 C57BL/6J@Ico (B6) and 5 C3H/HeJ@Ico (C3H) mice (5.5 months old) were explored. Mass density ρ, elastic coefficient c₁₁ and Young's modulus E₁ were locally derived in the distal epiphysis, distal metaphysis for trabecular bone and mid-diaphysis for cortical bone using a rule-of-mixture model. Structural parameter estimations obtained from X-ray tomographic and acoustic images were almost identical. Both strains had the same bone diameter, but the C3H mice had greater cortical thickness and smaller cancellous diameter than did B6 mice. The average DMB and impedance values were in the range between 1.13 and 1.33 g cm^− 3 and 5.8 and 7.8 Mrayl, respectively. All tissue parameters were lower in B6 mice than in C3H mice. However, interstrain differences of DMB were much less (up to 3.8%) than differences of Z (up to 13.2%). SAM and SR-μCT fulfill the requirement for a simultaneous evaluation of cortical bone microstructure and material properties at the tissue level. However, SAM provides a quantitative estimate of elastic properties at the tissue level that cannot be captured by SR-μCT. The strong differences in the measured acoustic impedances among the two inbred strains indicate that the impedance is a good parameter to detect genetic variations of the skeletal phenotype in small animal models.     

Targeted MYCN expression affects cytotoxic potential of chemotherapeutic drugs in neuroblastoma cells

Neuroblastoma (NB) is a solid childhood tumour that exhibits heterogeneous biological and clinical phenotypes. Multiple drug resistance marks a major complication especially in high-risk patients with advanced tumour stages and specific genetic aberrations, such as MYCN amplification and lp deletion. As an approach to further address the mechanisms of chemotherapeutic responsiveness of NB, we used a MYCN-inducible in vitro system and tested the susceptibility of NB cells to anti-tumour drugs currently included in NB treatment protocols dependent on MYCN expression. We observed cytotoxic effects using drug concentrations corresponding to blood plasma levels achieved in NB patients. The most potent drugs were microtubule inhibitors vindesin, paclitaxel and vincristin. Less effective were doxorubicine, arsenic trioxide, cisplatin, etoposide and carboplatin. Exposed to anti-tumour agents, NB cells with induced MYCN expression exhibited higher specific apoptosis than NB cells lacking MYCN expression. Anti-tumour drugs in MYCN-on cells accelerated G1-S phase transition, led to enhanced accumulation of cell populations in G2/M phase, and increased levels of apoptosis. In contrast, MYCN-off cell populations arrested in G1 and, to a smaller extent, in G2/M and exhibited delayed onset of apoptosis. In summary, apoptosis profiles and anti-proliferative potential of chemotherapeutic drugs, used at in vivo tolerable doses, are affected by MYCN overexpression and deregulated cell cycle in SH-EP(MYCN) cells.     

Feedback modeling of non-esterified fatty acids in obese Zucker rats after nicotinic acid infusions

This study investigates the impact of disease on nicotinic acid (NiAc)-induced changes in plasma concentrations of non-esterified fatty acids (NEFA). NiAc was given by constant intravenous infusion to normal Sprague–Dawley and obese Zucker rats, and arterial blood samples were taken for analysis of NiAc, NEFA, insulin and glucose plasma concentrations. The intravenous route was intentionally selected to avoid confounding processes, such as absorption, following extravascular administration. Data were analyzed using nonlinear mixed effects modeling (NONMEM, version VI). The disposition of NiAc in the normal rats was described by a two-compartment model with endogenous synthesis of NiAc and two parallel capacity-limited elimination processes. In the obese rats disposition was described by a one-compartment model with endogenous synthesis of NiAc and one capacity-limited elimination process. The plasma concentration of NiAc drove NEFA (R) turnover via an inhibitory drug-mechanism function acting on the formation of NEFA. NEFA turnover was described by a feedback model with a moderator distributed over a series of transit compartments, where the first compartment (M ₁ ) inhibited the formation of R and the last compartment (M _N ) stimulated the loss of R. All processes regulating plasma NEFA concentrations were assumed to be captured by the moderator function. Differences in the pharmacodynamic response of the two strains included, in the obese animals, an increased NEFA baseline, diminished rebound and post-rebound oscillation, and a more pronounced slowly developing tolerance during the period of constant drug exposure. The feedback model captured the NiAc-induced changes in NEFA response in both the normal and obese rats. Differences in the parameter estimates between the obese and normal rats included, in the former group, increases in R ₀ , k _in and p by 44, 41 and 78 %, respectively, and decreases in k _out and γ by 64 and 84 %, respectively. The estimates of k _tol and IC ₅₀ were similar in both groups. The NiAc–NEFA concentration–response relationship at equilibrium was substantially different in the two groups, being shifted upwards and to the right, and being shallower in the obese rats. The extent of such shifts is important, as they demonstrate the impact of disease at equilibrium and, if ignored, will lead to erroneous dose predictions and, in consequence, poorly designed studies. The proposed models are primarily aimed at screening and selecting candidates with the highest potential of becoming a viable drug in man.     

Impact of cardiovascular risk factors on vessel wall inflammation and calcified plaque burden differs across vascular beds: a PET-CT study

To evaluate the effect of age, gender and cardiovascular risk factors on vessel wall inflammation and the calcified plaque burden in different vascular beds as assessed by PET/CT. 315 patients (mean age: 57.8 years, 123 male and 192 female) who underwent whole body 18F-FDG PET/CT examinations were included in the study. Blood pool-corrected standardised uptake value (TBR) and the calcified plaque score (CPS, grade 0–4) were determined in the thoracic and abdominal aorta, both common carotid and both iliac arteries. The following cardiovascular risk factors were documented: Age ≥65 years (n = 114), male gender (n = 123), diabetes (n = 15), hyperlipidemia (n = 62), hypertension (n = 76), body mass index (BMI) ≥ 30 (n = 38), current smoker (n = 32). Effects of risk factors on TBR and CPS in different arterial beds were assessed using multivariate regression analysis. In the thoracic aorta TBR was independently associated with age ≥65 years and male gender, CPS was independently associated with age ≥65 years, male gender, hypertension and diabetes. In the abdominal aorta, TBR was independently associated with age ≥65 years and male gender, CPS with age ≥65 years, diabetes and smoking. Independent associations in the carotid arteries were found for age ≥65 years, male gender and BMI ≥ 30 in TBR and for age ≥65 and diabetes in CPS. In the iliac arteries, TBR was independently associated with age ≥65 and CPS with age ≥65, male gender, hypertension, diabetes and smoking. Findings of this PET/CT study demonstrate that the impact of cardiovascular risk factors on vessel wall inflammation and calcified plaque burden differs across vascular territories. Overall, CPS was more closely associated with cardiovascular risk factors compared to TBR.     

Acute Migraine Treatment With Rizatriptan in Real World Settings – Focusing on Treatment Strategy, Effectiveness, and Behavior

Although randomized controlled trials (RCTs) are the gold standard for assessing efficacy of a drug intervention, because they are conducted in a highly selected group of patients, they do not necessarily reflect normal customary or optimized patient care. Accordingly, information from RCTs must be supplemented by outcomes research and by nonexperimental or quasi-experimental study designs. Herein, we discuss information that supplements the rigorous but sometimes rigid nature of RCTs in an effort to better understand the clinical utility of drug treatment for migraine with patient-centered outcomes in mind. We start by discussing several lessons we learned from RCTs on comparative triptan studies, followed by presenting data on outcomes studies for rizatriptan. We then briefly discuss migraine treatment behavior issues, including early treatment and adherence to treatment.     

Intradermal Vaccinations With RNA Coding for TAA Generate CD8+ and CD4+ Immune Responses and Induce Clinical Benefit in Vaccinated Patients

The aim of this phase I/II nonrandomized trial was to assess feasibility, safety as well as immunological and clinical responses of a mRNA-based vaccination in patients with stage IV renal cell cancer using granulocyte-macrophage colony stimulating factor (GM-CSF) as adjuvant. Intradermal injections of in vitro transcribed naked mRNA, which was generated using plasmids coding for the tumor-associated antigens mucin 1(MUC1), carcinoembryonic (CEA), human epidermal growth factor receptor 2 (Her-2/neu), telomerase, survivin, and melanoma-associated antigen 1 (MAGE-A1) were performed in 30 enrolled patients. In the first 14 patients (cohort A) vaccinations were administered on days 0, 14, 28, and 42 (20 µg/antigen) while in the consecutive 16 patients (cohort B) an intensified protocol consisting of injections at days 0–3, 7–10, 28, and 42 (50 µg/antigen) was used. In both cohorts, after this induction period, vaccinations were repeated monthly until tumor progression analyzed by Response Evaluation Criteria In Solid Tumors criteria (RECIST). Vaccinations were well tolerated with no severe side effects and induced clinical responses [six stable diseases (SD) and one partial response in cohort A and nine SD in cohort B]. In cohort A, 35.7% survived 4 years (median survival 24 months) compared to 31.25% in cohort B (median survival 29 months). Induction of CD4⁺ and CD8⁺ T cell responses was shown for several tumor-associated antigens (TAA) using interferon-γ (IFN-γ) enzyme-linked immunosorbent spot (ELISpot) and Cr-release assays.