Effects of Formalin Fixation on Trace Element Concentrations in Bottlenose Dolphin (Tursiops truncatus) Tissues

Retrieval Analysis of the Essure® Micro Insert Female Sterilization Implant: Methods for Metal Ion and Microscopic Analysis

The Essure® Device is a female sterilization implant comprised of four alloys (Ni-Ti, 316L SS, Pt-Ir and Sn-Ag) and Dacron fibers. As part of the mandated 522 post-market surveillance study, implant retrieval and metal-ion analysis methods were developed separate from patient clinical data, to quantify trace metal ions found in tissue and to assess implant degradation present. Three segments of tissue (proximal implant, distal implant, and tissue distal from the implant) stored in neutral buffered formalin, were retrieved. Tissue was prepared for metal ion analysis using inductively coupled mass spectrometry (ICP-MS). Implant sections from four patients, were analyzed using digital optical microscopy (DOM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Image analysis showed Sn-Ag solder corroded and elevated Sn ion levels in tissue proximal to the solder compared to tissues more remote in all cases observed. The 316L SS exhibited signs of degradation with high surface concentrations of molybdenum and chromium and low iron compared to the parent alloy. Evidence of elevated iron, chromium and nickel within the tissues and storage solutions combined with precipitation of an iron-calcium-phosphorous material on some implants indicate evidence of SS corrosion. Ni-Ti, Pt-Ir and Dacron appear to have no major damage. This study includes preliminary results as part of the ongoing 522 study and therefore no final conclusions regarding the device or patient data can be drawn from this present study until the entire 522 study is complete. STATEMENT OF SIGNIFICANCE: The Essure Device is a female sterilization implant that was implanted into approximately 750,000 women. The device is composed of polyethylene terephthalate fibers and 4 metal alloys, 316L stainless steel, Nickel-Titanium, Tin-Silver and Platinum-Iridium. Following an increase in patient reported adverse events, the FDA required a 522-post market surveillance study. As part of this study, implants are retrieved from patients via salpingectomy or hysterectomy. This study focuses on the development of the implant retrieval methods following surgery, with focus on measuring local tissue metal ions, their distribution and assessing the degradation of the implant without correlation to patient clinical condition.

Pt(IV) Prodrugs with Non-Steroidal Anti-inflammatory Drugs in the Axial Position

We report herein the design, synthesis, and biological investigation of a series of novel Pt(IV) prodrugs with non-steroidal anti-inflammatory drugs naproxen, diclofenac, and flurbiprofen, as well as these with stearic acid in the axial position. Six Pt(IV) prodrugs 5-10 were designed, which showed superior antiproliferative activity compared to cisplatin as well as an ability to overcome tumor cell line resistance to cisplatin. By tuning the drug lipophilicity via variation of the axial ligands, the most potent Pt(IV) prodrug 7 was obtained, with an enhanced cellular accumulation of up to 153-fold that of cisplatin and nanomolar cytotoxicity both in 2D and 3D cell cultures. Pt²⁺ species were detected at different depths of MCF-7 spheroids after incubation with Pt(IV) prodrugs using a Pt-coated carbon nanoelectrode. Cisplatin accumulation in vivo in the murine mammary EMT6 tumor tissue of BALB/c mice after Pt(IV) prodrug injection was proved electrochemically as well. The drug tolerance study on BALB/c mice showed good tolerance of 7 in doses up to 8 mg/kg.

Determination of trace elements in placenta by total reflection X-ray fluorescence spectrometry: effects of sampling and sample preparation

Placental elemental composition can serve as an indicator for neonatal health. Medical studies aiming at revealing such cause-and-effect relationships or studies monitoring potential environmental influences consist of large sample series to ensure statistically sufficient data. Several analytical techniques have been used to study trace metals in human placenta. However, most techniques require provision of clear liquid sample solutions and therefore time- and reagent-consuming total digestion of biological tissue is necessary. In total reflection X-ray fluorescence spectrometry (TXRF)-a straightforward multielement analytical technique-in contrast suspensions of minute sample amounts can be analyzed directly. Therefore, herein we report on a valid method to prepare homogenous sample suspensions for sustainable and fast TXRF analysis of large sample series. The optimized method requires only 10 mg of powdered placental tissue and 1 mL nitric acid. Suspensions are readily prepared within 30 min and the found mass fractions of major, minor, and trace elements are in good agreement in comparison to analysis of digests. In addition, possible effects on fixation time and the exact sampling location, i.e., maternal vs. fetal side of the placenta, were studied applying this method. Thereby, significant differences for fetal placenta tissue compared to maternal or intermediate tissue were observed revealing accumulation of trace elements in the fetal side of the placenta. Furthermore, considerable depletion of up to 60% mass fraction with longer fixation duration occurred in particular in fetal placenta tissue. These findings help to understand the large ranges of mass fraction of elements in placenta reported in the literature and at the same time indicate the necessity for more systematic investigation of non-homogenous elements distributed in placenta taking sampling and stabilization methods into account.

In Vitro/In Vivo Electrochemical Detection of Pt(II) Species

The biodistribution of chemotherapy compounds within tumor tissue is one of the main challenges in the development of antineoplastic drugs, and techniques for simple, inexpensive, sensitive, and selective detection of various analytes in tumors are of great importance. In this paper we propose the use of platinized carbon nanoelectrodes (PtNEs) for the electrochemical detection of platinum-based drugs in various biological models, including single cells and tumor spheroids in vitro and inside solid tumors in vivo. We have demonstrated the quantitative direct detection of Pt(II) in breast adenocarcinoma MCF-7 cells treated with cisplatin and a cisplatin-based DNP prodrug. To realize the potential of this technique in advanced tumor models, we measured Pt(II) in 3D tumor spheroids in vitro and in tumor-bearing mice in vivo. The concentration gradient of Pt(II) species correlated with the distance from the sample surface in MCF-7 tumor spheroids. We then performed the detection of Pt(II) species in tumor-bearing mice treated intravenously with cisplatin and DNP. We found that there was deeper penetration of DNP in comparison to cisplatin. This research demonstrates a minimally invasive, real-time electrochemical technique for the study of platinum-based drugs.