Effect of selected fluorinated drugs in a "ringing" gel on rheological behaviour and skin permeation.

The purpose of the present study was to investigate the influence of different drugs exhibiting different solubility on the viscoelastic properties and on the skin diffusion profile of a ringing gel. In a preliminary rheology study with the placebo gel predominating elastic properties were confirmed and a temperature influence was indicated. Fluconazole, fludrocortisone-acetate, flumethasone-pivalate, flutamide and flufenamic-acid each 1% (w/w) were incorporated into the preparation and oscillatory measurements were performed at temperatures of 25, 28, 32 and 37 degrees C. In all drug containing formulations a high elastic G' value predominated the viscous G' value. The highest G' value could be obtained with the incorporated flumethasone-pivalate. Additionally in almost all cases the G' values decreased with increasing temperature compared to the placebo gel. Additionally in vitro standard diffusion experiments using Franz-type cells and porcine skin were performed. Following rank order of the cumulative drug release after 48 h was obtained: fluconazole>flufenamic-acid>flumethasone-pivalate>flutamide>fludrocortisone-acetate. Furthermore an excellent chemical stability of all incorporated drugs was confirmed over 10 weeks.     

Triterpenoid saponins, new metalloprotease snake venom inhibitors isolated from Pentaclethra macroloba.

We report here the antiproteolytic and antihemorrhagic properties of triterpenoid saponin inhibitors, named macrolobin-A and B, from Pentaclethra macroloba, against Bothrops snake venoms. The inhibitors were able to neutralize the hemorrhagic, fibrin(ogen)olytic, and proteolytic activities of class P-I and P-III metalloproteases isolated from B. neuwiedi and B. jararacussu venoms. Clotting and fibrinogenolytic activities induced by snake venoms and isolated thrombin-like enzymes were partially inhibited. Furthermore, the potential use of these inhibitors to complement antivenom therapy as an alternative treatment and/or used as molecular models for development of new therapeutical agents in the treatment of snake bite envenomations needs to be evaluated in future studies.     

Gating modifier toxins of voltage-gated calcium channels.

Some of the most potent and specific inhibitors of voltage-gated calcium channels are peptide toxins that inhibit channel function not by occlusion of the channel pore, but rather by interfering with the voltage dependence and kinetics of channel opening and closing. Many such gating modifier toxins conform to the inhibitor cystine knot structural family and have primary sequence or functional mechanism similar to toxins that target voltage-gated sodium or potassium channels. This review introduces known gating modifiers of calcium channels, discusses the selectivity, binding sites, and mechanism of the toxin-channel interaction, and reviews the usefulness of these toxins as research tools and as the basis for novel calcium channel pharmacology and therapeutics.     

Platelet function in patients with acute coronary syndrome (ACS) predicts recurrent ACS

BACKGROUND: Platelet hyperfunction contributes to acute coronary syndromes (ACS). Thus, we hypothesized that platelet function under high shear stress predicts recurrent ACS during long-term follow-up of ACS patients. PATIENTS AND METHODS: Consecutive ACS patients (n = 208) were prospectively followed-up for an average of 28 months. Platelet function was measured with the platelet function analyzer (PFA-100; Dade Behring, Marburg, Germany) at baseline for collagen/adenosine diphosphate closure times (CADP-CT) and for collagen/epinephrine closure times (CEPI-CT) after infusion of a uniform dose of 250 mg aspirin. RESULTS: Of the conventional risk factors, only the prevalence of diabetes was higher in ACS patients with re-events. However, use of clopidogrel and use of beta blockers were also slightly lower in patients with re-events (P < 0.05). The unadjusted risk hazard ratio (HR) for re-events was 3.3 [95% confidence interval (95% CI): 1.4-7.4; P = 0.005] in those patients with the shortest CADP-CT values (lowest quartile). Similarly, the risk was 2.0-fold higher (95% CI: 1.1-3.6; P = 0.02) in ACS patients with CEPI-CT < 300 s as compared with CEPI-CT >or = 300 s. Inclusion of diabetes, clopidogrel and beta blockers in a multivariate Cox regression model enhanced the predictive value of CEPI-CT (HR: 2.7). Inclusion of von Willebrand factor levels did not alter the HR for recurrent ACS (HR: 2.1; 95% CI: 1.1-5.2; P = 0.03) for CEPI-CT < 300 s, but reduced the HR for CADP-CT (HR: 2.8, 95% CI: 0.8-9.8; P = 0.11). CONCLUSION: Shortened CT values reflect biologically relevant platelet hyperfunction in patients with ACS because they predict recurrent ACS.     

Electron inelastic mean free path formula and CSDA-range calculation in biological compounds for low and intermediate energies.

In this study, for low atomic number targets and biological compounds, an inelastic mean free path (IMFP) formula and energy straggling parameter formula are presented, being valid for low and high electron energies. In addition, calculation of the continuous slowing down approximation-range (CSDA-range) from the stopping power is also made. The IMFP and the energy straggling parameter formulae are evaluated using the generalized oscillator strength (GOS) model and the exchange correction to the inelastic differential cross section (IDCS) given by Inokuti, M., [1978. Inelastic collisions of fast charged particles with atoms and molecules--the Bethe theory revisited. Rev. Mod. Phys. 50, 23-35]. The IMFP and CSDA-range for the biological compounds C5H5N5 (adenine), C5H5N5O (guanine), C4H5N3O (cytosine), C5H6N2O2 (thymine), C20H27N7O13P2 (cytosine-guanine) and C19H26N8O13P2 (thymine-adenine) have been introduced for incident electrons in the energy range 20 eV-1 MeV. The calculated results are compared with semi-empirical results and other theoretical results, good agreement being found with experimental data and Monte Carlo (PENELOPE code) predictions. All the IMFP versus energy curves exhibit minima around 80 eV.     

Causes of B chromosome variant substitution in the grasshopper Eyprepocnemis plorans

We have analysed B chromosome frequency for three consecutive years, B transmission rate at population and individual levels, clutch size, egg fertility and embryo–adult viability in a natural population of the grasshopper Eyprepocnemis plorans containing two different B chromosome variants, i.e. B₂ and B₂₄, the second being derived from the first and having replaced it in nearby populations. From 2002 to 2003 the relative frequency of both variants changed, although the differences did not reach significance. A mother–offspring analysis showed no significant effect of any of the two B variants on clutch size, egg fertility or embryo–adult viability, but B₂₄ was more efficiently transmitted than B₂ through males from the 2002 season, which explains the observed frequency change. Controlled crosses, at individual level, showed significant drive through some females for B₂₄ but not for B₂, suggesting that this difference in transmission rate might also be important for the substitution process. The analysis of relative fitness for B₂ and B₂₄ carriers for all fitness components, as a whole, showed a significantly better performance of B₂₄-carrying individuals, suggesting that the cumulative effect of these slight differences might contribute to the replacement of B₂ by B₂₄. Electronic Supplementary Material Supplementary material is available for this article at .     

The advisory process for anticancer drug regulation: a global perspective.

PURPOSE: This paper summarizes the role of external advisors in oncology drug development and regulation from a global perspective. DESIGN: Recently, representatives from the United States Food and Drug Administration, European Medicines Agency, the Japanese Pharmaceuticals and Medical Devices Agency, the Australian Therapeutic Goods Administration and Health Canada held a meeting in conjunction with the American Society of Clinical Oncology meeting. The role of external advisors in oncology drug development and regulation in each of these jurisdictions was presented and discussed. RESULTS: All regulatory bodies described have experience with two forms of outside expertise: advice from individual experts and advice from a group of experts assembled as an advisory group. Regulatory jurisdictions use individual experts variably. In some regions, individual experts provide advice based on knowledge and experience during the drug development phase or in the planning phase for the submission of a drug registration package. In other regions, these individuals serve as external evaluators with the primary responsibility for the review of a clinical trials package submitted for drug registration. Advisory boards have been formalized in all jurisdictions discussed. Advisory boards have a role in discussing specific applications as well as broad policy issues. A common theme is a composition of a core panel of experts with augmentation by additional expertise as needed for consideration of specific scientific questions. In all jurisdictions, advisory board recommendations are not binding on the regulatory body. CONCLUSIONS: Global oncology drug development and registration involves the use of experts by regulatory authorities. The types of experts needed, the expert's role and the transparency of the advisory process reflect the individual needs in different regions.