Evaluation of surface characteristics of titanium and cobalt chromium implant abutment materials.

INTRODUCTION: Micro-organism adhesion and plaque formation is affected by surface free energy (SFE), surface roughness, hydrophilicity, surface chemistry, surface charge and the presence of proteins. AIMS: The aim of this study was to assess and compare surface characteristics of surgical grade cobalt chromium alloy (CCM) and of commercially pure titanium (cpTi). METHOD: Nine metallic cylinders were machined to precise standards from each material. Surface roughness was measured at four different points on each sample and the average Ra value was calculated for each material. Contact angles were obtained using the sessile-drop method and applied in calculating the SFE. Surface hardness was evaluated by means of a Vickers hardness micro-indentation. RESULTS: Surface roughness was similar for both metals, but total SFE values and Vickers surface hardness scores showed significant differences (p < 0.0001). CONCLUSION: SFE analysis showed CCM to be more hydrophobic and that oral bacteria might therefore be less adherent than to cpTi. The mean Vickers Hardness scores of the cpTi were significantly lower (p < 0.0001), suggesting that CCM may be more resistant to surface modifications and surface roughening, thus remaining smoother with less plaque accumulation than cpTi. This study demonstrated that CCM might be a suitable alternative implant abutment material.

In vitro effects of 2-methoxyestradiol on morphology, cell cycle progression, cell death and gene expression changes in the tumorigenic MCF-7 breast epithelial cell line.

In the present study, the antiproliferative mechanism of action of 1 microM 2-methoxyestradiol (2ME) was investigated in the MCF-7 cell line. Measurement of intracellular cyclin B and cytochrome c protein levels, reactive oxygen species formation, cell cycle progression and apoptosis induction were conducted by means of flow cytometry. Morphological changes were evaluated using transmission electron microscopy and fluorescent microscopy by employing Hoechst 33342 and acridine orange. Gene expression changes were conducted by means of microarrays. 2ME-treated cells demonstrated an increase in cyclin B protein levels, hydrogen peroxide formation, intracellular levels of cytochrome c, as well as an increase in early and late stages of apoptosis. In addition, morphological data revealed the presence of autophagic processes. Fluorescent microscopy showed an increase in acridine orange staining and electron microscopy revealed an increase in vacuolar formation in 2ME-treated cells. The gene expression of several genes associated with mRNA translation, autophagy-related processes and genes involved in microtubule dynamics were affected. The study contributes to the mechanistic understanding of 2ME's growth inhibition in MCF-7 cells and highlights the possibility of both apoptotic and autophagic processes being activated in response to 2ME treatment in this cell line.

Ion exchange separation of strontium and rubidium on Dowex 50W-X8, using the complexation properties of EDTA and DCTA.

A chromatographic method for separation of strontium from rubidium, using the unique alkaline-earth metal complexation ability of the carboxylic acids EDTA and DCTA is proposed. The method was developed in order to improve the effectiveness of (87)Sr/(86)Sr isotope studies with ICP-QMS. Due to the isobaric overlap of (87)Rb with (87)Sr, strontium needs to be separated from rubidium prior to sample analysis with ICP-QMS. The method involves the retention of strontium, calcium, magnesium, and rubidium on Dowex 50W-X8 resin in its NH(4)(+) form, followed by elution of the divalent cations as metal EDTA or DCTA complexes. Because divalent cations have different EDTA and DCTA complex formation constants, it is possible to separate them under the correct conditions. Neither EDTA nor DCTA form complexes with alkali metals, thus rubidium remains retained by the column and is later eluted using HNO(3). Both EDTA and DCTA elution methods were tested with different concentrations of the elements to determine the effect of increased concentration on separation efficiency. The EDTA elution procedure was proved to be effective in separating strontium from both calcium and rubidium, while the DCTA method was found to be even more effective, because strontium is separated from all the elements involved in this study.

[Medical expert assessment and civil and criminal law from the viewpoint of arbitration services and the expert committee]. / Arztliche Begutachtung in Zivil- und Strafrecht aus der Sicht der Schlichtungsstellen und der Gutachterkommissionen.

The procedures of the arbitration committee of north Germany for medical liability claims are discussed. This procedure is set into relation to that at court. Due to the continuously maintained communication between lawyers and physicians, which does not occur in a comparable manner in court, the choice to proceed at a arbitration committee and an expert board is seen as more useful and pertinent than at court. This is specifically explained.

[Expert testimony in malpractice from the physician's viewpoint]. / Begutachtung bei Haftungsfragen aus ärztlicher Sicht.

The believe on the civilizatory progress serving mankind goes along with the realization that it cannot keep up with humanity. Anxieties grow from this realization which extend to the relationship between physicians and patients and, therefore, also apply to disputes about liability.

The prognostic value of serum human placental lactogen determinations in early pregnancy.

Serial serum human placental lactogen (S-HPL) determinations were done in early pregnancy on 85 high-risk cases. Normal S-HPL values with a normal ultrasonogram had a 94.8 per cent successful outcome of pregnancy. Low S-HPL values were often accompanied by an abnormal or equivocal ultrasonogram (29.6 per cent). The fetal loss in patients with low S-HPL values and a normal ultrasonogram was 36.8 per cent.

Treatment of threatened and habitual abortion with human chorionic gonadotrophin. The role of serum human placental lactogen determination.

Treatment of habitual and threatened abortion with human chorionic gonadotrophin (HCG) is discussed. Two problems are encountered: the selection of patients for treatment; and the correct dosage of HCG. Determination of human placental lactogen (HPL) in the serum was used to select patients for treatment. The dosage of HCG was varied according to the response of the patient and as indicated by the levels of HPL in her serum.