Influence of analyzed lubricant volumes on the amount and characteristics of generated wear particles from three different types of polyethylene liner materials.

The articulating components of artificial joints consist mainly of metals, ceramics, or polymers. Resulting abrasive wear particles can promote osteolysis and aseptic loosening of the endo-prosthetic implants. Ultra-high-molecular-weight-polyethylene is the material used most for bearing couples in total hip replacement. In the present study, three types of polyethylene (PE) liners varying in material composition, i.e., (1) conventional PE (C-PE), (2) sequentially cross-linked PE (SX-PE), (3) cross-linked PE blended with vitamin E (EX-PE) articulating with two types of femoral heads were used. After ultrasound treatment of each simulator lubricant, different concentrations (0.1/0.25/0.5/1.0 mL) were taken and dissolved in hydrochloric acid (37%) in a similar manner. The aim was to analyze the characteristics of wear particles generated in a hip simulator, with respect to different volumes of the lubricant. Within the scope of particle analysis, distinct alterations for particle characteristics were determined in the lubricant volumes and types of PE material used. A significant decrease in particle number for SX-PE liners, compared to the C-PE inserts and even more for EX-PE inserts, was detected at each lubricant volume. Particle morphologies varied depending on PE material. Alterations in particle size and other morphologic parameters between the four tested volumes, could be proven for each PE type. In general, particle sizes and parameters (e.g., length and width) increased with increasing serum volumes. In conclusion, the chosen volume of the simulator lubricant used for particle analysis has a crucial influence on detected particle number, size distribution, and morphologic parameters. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1299-1306, 2018.

Rapid and reliable detection of bacterial endospores in environmental samples by diagnostic electron microscopy combined with X-ray microanalysis.

Diagnostic negative staining electron microscopy is a front-line method for the rapid investigation of environmental and clinical samples in emergency situations caused by bioterrorism or outbreaks of an infectious disease. Spores of anthrax are one of the diagnostic targets in case of bioterrorism, because they have been used as a bio-weapon in the past and their production and transmission are rather simple. With negative staining electron microscopy bacterial spores can be identified based on their morphology at the single cell level. However, because of their particular density, no internal structures are visible which sometimes makes it difficult to distinguish spores from particles with a similar size and shape that are frequently present in environmental samples. Spores contain a high concentration of calcium ions besides other elements, which may allow a proper discrimination of spores from other suspicious particles. To investigate this hypothesis, negative staining electron microscopy, using either transmission or scanning electron microscopes, was combined with energy dispersive X-ray microanalysis, which reveals the element content of individual nanoparticles. A peak pattern consisting of calcium, sulphur and phosphorus was found as a typical signature within the X-ray spectrum of spores in various Clostridium and Bacillus species, including all strains of anthrax (Bacillus anthracis) tested. Moreover, spores could be reliably identified by this combined approach in environmental samples, like household products, soil or various presumed bioterrorist samples. In summary, the use of X-ray spectroscopy, either directly in the transmission electron microscope, or in a correlative approach by using scanning electron microscopy, improves the emergency diagnostics of suspicious environmental samples.

Wear testing and particle characterisation of sequentially crosslinked polyethylene acetabular liners using different femoral head sizes.

Larger femoral heads lead to a decreased risk of total hip dislocation and an improved range of motion. However, the larger diameter is associated with increased wear rates. The low wear rates of crosslinked polyethylene opens up the possibility of using larger heads. The aim of this experimental study was to evaluate the wear of conventional non-crosslinked versus sequentially crosslinked polyethylene liners in combination with different ceramic head sizes (28, 36, 44 mm). Wear testing was performed in a hip simulator according to ISO 14242. Wear particles from the polyethylene liners were characterized after wear testing. The wear measurements revealed a significant increase in the wear of crosslinked polyethylene liners with larger heads. By sequential crosslinking, however, the gravimetric wear using larger heads was reduced to a fractional amount of the wear using conventional polyethylene. Significant differences were observed for particle morphology but not for the number of particles when comparing non-crosslinked and crosslinked polyethylene.

Ossification of the frontal sinus in juvenile minipigs following water jet application.

BACKGROUND: Obliteration of the frontal sinus is a generally accepted management for patients with severe craniofacial trauma in whom the sinus cannot be repaired or adequately drained. Effective obliteration requires complete removal of mucosa, sufficient filling of the sinus cavity as well as effective occlusion of the nasofrontal duct. The use of various filling materials for sinus obliteration has been described and include autologous fat, bone, muscle and lyophilized cartilage. MATERIAL AND METHODS: In order to appreciate the advantages of the water-jet scalpel an animal study in 10 juvenile (4 months old) and 10 adult (18 months) minipigs was performed. In 5 juvenile and 5 adult animals the frontal sinus mucosa was removed using the water jet, while in the others bone curettes were used. No occlusion of the frontonasal duct was carried out and no filling material was implanted. All animals were followed-up for 40 days. After sacrifice, radiological, histological and computerized histomorphometrical examinations were carried out. RESULTS: Removal of the mucosa from the sinus was simplified when using the water jet. Previous studies have shown that the selected tissue structures were less traumatized when compared with conventional surgical techniques. In young animals (only) and exclusively following the use of a water-jet scalpel osseous occlusion of the frontal sinus was found at follow-up. Histomorphometric findings revealed a significant increase of bone formation in the frontal sinus area of these animals. CONCLUSION: Based on these experimental results in a small series of juvenile minipigs the water-jet technique is a faster and less traumatic technique (less blood loss) for osteoplastic surgery of the frontal sinus. Further long-term studies are needed to evaluate the possibilities for applying this technique in post-traumatic craniofacial surgery in man.

Detection of gold particles in the neck skin after lightning stroke with evaporation of an ornamental chain.

A German couple was struck by lightning. Both patients survived this event. Whereas the husband was unconscious for only a few minutes, his wife fell into coma for 24 h. The lightning stroke entered the body of the woman behind the left ear and left it at the left shoe. The stroke caused a partial evaporation of a gold ornamental chain on the neck, resulting in a tattoo of the neck skin. A biopsy of the skin 6 months after the event showed the accumulation of gold particles of different size in the dermis down to the subcutaneous fatty tissue. In semithin sections, histiocytes, multinucleated foreign giant cells, and fibroblasts were visible with uptaken metallic particles. In transmission electron microscopy, gold globules of up to 30 microm in diameter were visible outside the cells in the collageneous matrix of the connective tissue besides smaller metallic particles up to 5 nm inside lysosomes and residual bodies of phagocytic cells. Four different kinds of gold particles could be differentiated: globules, granular irregular particles, tubules, and tanglelike tracks. In scanning electron microscopy, gold particles were demonstrated by backscatter detection in the connective tissue of subcutis, where the EDX elemental analysis showed strong signals of aurum (Au), copper (Cu), and argentum (Ag). The detected metals were quantified by AAS as 70% gold, 21% silver, and 9% copper, which demonstrates the composition of gold alloy of the neck chain of the patient. Tanglelike tracks and elongated gold deposits represent crystals of gold salts, as detected by electron diffraction and polarization microscopy. Attempts to remove the gold particles from the skin to remove the tattoo should not be undertaken because the gold is deep and widespread.

Hereditary hemochromatosis of a young girl: detection of early iron deposition in liver cell lysosomes using transmission electron microscopy and electron energy loss spectroscopy.

A 14-year-old girl demonstrated increased iron concentration and transferrin saturation, suggesting iron overload of unknown origin. Liver biopsy showed no fibrosis or hepatocytic atrophia. Nevertheless, Prussian blue reaction for histochemical detection of iron demonstrated very weak positive granules in a few hepatocytes on the periphery of hepatic lobules in close connection to bile capillaries. This very early stage of hemochromatosis was confirmed by TEM and EELS for iron accumulation inside hepatocytic lysosomes and residual bodies. Such siderosomes were scarce in number and iron content, compared to a case of manifested hemochromatosis and liver cirrhosis (Jonas L, Fulda G, Salemeh T, et al. Ultrastruct Pathol. 2001; 25: 111-118.). Liver iron concentration as measured by inductively coupled plasma-mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS) yielded 2.005 mg/g tissue dry weight, which was considered not significantly increased. In the absence of known causes for secondary iron overload, the early diagnosis was evidenced by genotyping, revealed homozygosity for the HFE gene C282Y mutation, demonstrating the presence of hereditary hemochromatosis.

Electron microscopic detection of tin accumulation in biliopancreatic concrements after induction of chronic pancreatitis in rats by di-n-butyltin dichloride.

The organotin compound di-n-butyltin dichloride (DBTC) is able to induce an acute and later a chronic pancreatitis in rats. In previous papers the authors demonstrated this DBTC pancreatitis as a rat model for an interstitial pancreatitis with tendency to transduction to the chronic form. DBTC is excreted according to its lipophilic nature by liver and bile. Therefore, the bilio-pancreatic main duct is necrotized by the tin-loaded bile. The duct system is blocked by cell debris and later by epithelial proliferations. In the chronic phase, numerous rats develop concrements in the main duct. In the present paper, the authors report about bacterial growth in some bilio-pancreatic concrements. Whereas the electron microscopic detection of tin by energy-dispersive X-ray analysis (EDX) in SEM or electron energy loss spectroscopy (EELS) in TEM was negative in the parenchyma of pancreas and liver, some concrements with bacterial cells were positive for this element. Tin mapping with energy spectroscopic imaging (ESI) in TEM demonstrated the congruency of tin signals and electron-dense particles inside these bacteria and of electron-dense accumulations in the matrix of these concrements. The low content of tin in pancreatic and liver tissue and the higher quantity of tin inside the bacterial contaminated concrements were supported by atomic absorption spectrophotometry (AAS). The paper discusses the long time preservation of tin in the concrements as an action of heavy-metal- accumulating bacteria, which should be classified in the future by bacteriological methods.