Transorbital embolization of cavernous sinus dural arterio-venous malformations with surgical exposure and catheterization of the superior ophthalmic vein.

PURPOSE: Cavernous sinus dural arterio-venous malformations (dAVF) represent a pathologic connection between branches of the internal and/or external carotid artery and the cavernous sinus. Standard endovascular approaches for dAVF treatment are transvenous embolization through the inferior petrosal sinus or the facial vein and transarterial embolization. These approaches are not always successful or feasible, and alternative techniques are required. Here, we present a case series of a minimally invasive transorbital approach with surgical exposure and catheterization of the superior ophthalmic vein for transvenous fistula coiling. METHODS: 14 patients with dAVFs (Barrow Type B to D) that were treated at a tertiary care medical center over a period of 13 years were included in the study. Patients with persisting dAVF associated symptoms were selected for this approach when conventional endovascular interventions were not successful or not feasible. The surgical procedure was performed under general anaesthesia. RESULTS: A successful transorbital approach was performed in all 14 cases. In 12 of 14 patients a catheter assisted successful embolization of the fistula was performed using platinum coils with no relevant residual fistula flow. In two cases, a spontaneous thrombosis of the fistula during the surgical procedure required no further embolization. No postoperative therapy-associated complications were observed. CONCLUSION: The described approach is an effective method to embolize dAVFs in selected cases when catheter assisted transvenous and/or transarterial embolization is not successful or not feasible. In this case series we demonstrate an excellent success rate with no therapy-associated major complications.

Auricular reconstruction with polyethylene implants or silicone prosthesis: A single institution experience.

Auricular reconstruction is usually necessary in patients with congenital malformations, after traumatic ear amputations or in cases of neoplastic ear disease. Thirty-nine patients who underwent an auricular reconstruction with either silicon prosthesis (21 patients) or porous polyethylene (18 patients) between 2002 and 2013 were retrospectively analyzed at a tertiary academic institution. A total of 25 male und 14 female patients were included in the study. In all, 43 implants were installed in 39 patients. An implant failure was not observed in any of the examined groups. An operative revision was necessary in 5 patients in the silicon prosthesis group (N = 21) and in 4 patients in the porous polyethylene group (N = 18). The most common side effect in the porous polyethylene group was the formation of retroauricular adhesions in 11.1 % by postoperative scaring, while in the silicone prosthesis group 71.4 % of the patients presented with skin reactions around the titanium implants. Our study shows that both techniques are valuable and should be offered to patients in cases of auricular reconstruction due to the low rate of severe complications and the good functional results of both techniques.

Specific enrichment of prokaryotic DNA using a recombinant DNA-binding protein.

Targeted enrichment of DNA is often necessary for its detection and characterization in complex samples. We describe the development and application of the novel molecular tool for the specific enrichment of prokaryotic DNA. A fused protein comprising the DNA-binding subunit of the bacterial topoisomerase II, gyrase, was expressed, purified, and immobilized on magnetic particles. We demonstrated the specific affinity of the immobilized protein towards bacterial DNA and investigated its efficiency in the samples with high background of eukaryotic DNA. The reported approach allowed for the selective isolation and further detection of as few as 5 pg Staphylococcus aureus DNA from the sample with 4 × 10(6)-fold surplus of human DNA. This method is a promising approach for the preparation of such type of samples, for example in molecular diagnostics of sepsis.

Gene silencing of chordin improves BMP-2 effects on osteogenic differentiation of human adipose tissue-derived stromal cells.

Although bone morphogenic protein (BMP)-2 is known to potently induce osteogenic differentiation of human mesenchymal stem cells, strong individual differences have been reported. In part, this is due to internal antagonists of BMP-2 for example, noggin and chordin, secreted by differentiating cells. This enabling study was performed to prove the hypothesis that osteogenic effects of BMP-2 can be improved by transient nonviral gene silencing of chordin. We investigated the effect of siRNA against chordin on osteogenic differentiation in human adipose tissue-derived stromal cells (hASC). Cells of two different donors were isolated after liposuction and proliferated for passage 4 or 5. On seeding, hASCs were transfected with siRNA using a commercial liposomal transfection reagent. Subsequently, cells were differentiated in the presence or absence of BMP-2 (100 ng/mL). Noncoding siRNA as well as siRNA against noggin served as a control. Osteogenic differentiation of hASC was determined by alkaline phosphase (ALP) activity and matrix mineralization. ALP activity of hASC treated with siRNA against chordin was increased for cells of both donors. In contrast, silencing of noggin had no effect in any of the donors. In combination with BMP-2, silencing of either chordin or noggin showed strongly improved ALP activity compared with the control group that was also supplemented with BMP-2. Mineralization was observed to start earlier in groups that received siRNA against chordin or noggin and showed increased amounts of incorporated calcium on day 15 compared with the control groups. Silencing chordin in hASCs was successful to increase BMP-2 effects on osteogenic differentiation in both donors, while effects of noggin silencing were reliably observed only in one of the two investigated donors. In contrast to noggin silencing, chordin silencing also increased osteogenic differentiation without supplemented BMP-2.

Vitalization of porous polyethylene (Medpor®) with chondrocytes promotes early implant vascularization and incorporation into the host tissue.

Porous polyethylene (Medpor(®)) is frequently used in craniofacial reconstructive surgery. The successful incorporation of this alloplastic biomaterial depends on adequate vascularization. Here, we analyzed whether the early vascularization of porous polyethylene can be accelerated by vitalization with human chondrocytes. For this purpose, small polyethylene samples were coated with platelet-rich plasma (PRP) or a suspension of PRP and human chondrocytes. Uncoated polyethylene samples served as controls. Subsequently, the samples were implanted into the dorsal skinfold chamber of CD-1 nude mice to repetitively analyze their vascularization and biocompatibility by means of intravital fluorescence microscopy. PRP-chondrocyte-coated polyethylene exhibited an accelerated and improved vascularization when compared with the other two groups. This was indicated by a significantly higher functional capillary density of the microvascular network developing around the implants. Moreover, a leukocyte-endothelial cell interaction was found in a physiological range at the implantation site of all three groups, demonstrating that the vitalization with PRP and chondrocytes did not affect the good biocompatibility of the alloplastic material. Additional histological, immunohistochemical, and in situ hybridization analyses revealed that the chondrocytes formed a bioprotective tissue layer, which prevented the accumulation of macrophages and foreign body giant cells on the polyethylene surface. These findings clearly indicate that vitalization of polyethylene with chondrocytes promotes early implant vascularization and incorporation into the host tissue and, thus, may be a promising approach that prevents postoperative complications such as implant extrusion, migration, and infection.

SiGe epitaxy on a 300 mm batch furnace.

This work reports the feasibility of silicon and silicon germanium epitaxy using an ASM A412(TMa) LPCVD all quartz, hot wall, vertical batch furnace reactor using 100 wafer product loads. The very same furnace can be used for 25 wafer and 200 wafer load size, without any hardware changes, dependant on production needs. Following this approach a significant cost reduction for epitaxy in 300 mm high volume manufacturing is possible and enables new applications. The native oxide of the substrate was removed by wet chemical cleaning with time coupling of less than 1 h and subsequent in-situ low pressure hydrogen anneal prior to Si or SiGe deposition. The epitaxial layers were grown using silane and germane. The Si and SiGe layers have been characterized with ToFSIMS, XRD, Raman, AFM and TEM confirming excellent crystalline quality, layer thickness and within wafer SiGe stoichiometry uniformity.

Ear reconstruction with porous polyethylene implants.

This article describes a surgical technique using porous polyethylene as the framework material for ear reconstruction. In comparison to the use of rib cartilage, porous polyethylene - first described by Berghaus in 1982 - provides better definition and projection as well as congruency with the opposite side. Hospitalization time is significantly shorter. There are less surgical interventions than with traditional microtia operations that use rib cartilage, and the patient is spared the additional procedure needed to remove the rib cartilage, with all the associated complications as well as the resulting thorax scar. Also, reconstruction can take place at an earlier age, which is advantageous for those concerned. Using porous polyethylene as the frame material, a temporoparietal flap and full-thickness skin cover, we have been able to achieve very convincing results over recent years.

Alpha2-macroglobulin inhibits the malignant properties of astrocytoma cells by impeding beta-catenin signaling.

Targets that could improve the treatment of brain tumors remain important to define. This study of a transformation-associated isoform of alpha2-macroglobulin (A2M*) and its interaction with the low-density lipoprotein receptor-related protein-1 (LRP1) suggests a new mechanism for abrogating the malignant potential of astrocytoma cells. LRP1 bound A2M* found to be associated with an inhibition of tumor cell proliferation, migration, invasion, spheroid formation, and anchorage-independent growth. Transcriptional studies implicated effects on the Wnt/beta-catenin signaling pathway. Notably, LRP1 antibodies could phenocopy the effects of A2M*. Our findings suggest a pathway of tumor suppression in astrocytoma that might be tractable to therapeutic exploitation.

Tumor risk assessment by means of immunocytochemical detection of early pre-malignant changes in buccal smears.

Increasing incidence of carcinomas in the upper aero-digestive tract, both in Germany and in other European countries requires development of new preventive strategies. The cure rate at advanced tumor stages remains poor in spite of a variety of available therapeutic methods. In the present study the quantitative assessment of a pre-malignant mucosa lesion within a field cancerization was performed by means of immunocytochemical methods. This may allow individuals with an increased risk of developing malignant disease to be identified. Cytosmears taken from healthy buccal mucosa of tumor patients (n=50) and from healthy probands (n=100) with different tobacco and alcohol consumption levels were examined with regard to identifying increased expression of the proliferation markers (PCNA, MIB1), of the tumor suppressor gene product p53 as well as the oncogene product cyclin D1. There was a significant difference in expression of investigated proliferation markers between tumor patients and healthy probands (p<0.0001). When comparing the rate of positively marked cell nuclei to cigarette pack years the marker cyclin D1 and MIB1 show an increased rate in the groups with high tobacco consumption as compared to the group with a low exposure (p>0.05). It could be possible to use the marker MIB1 and cyclin D1 to screen risk groups, since the relative morbidity risk (odds ratio) increases (by 45-62 times) if the threshold value of 4 positively marked cell nuclei is exceeded.

VCAM-1 increases levels of HGF in eosinophilic chronic rhinosinusitis cell culture.

BACKGROUND: Eosinophilic chronic rhinosinusitis (ECRS) is one of the most common diseases worldwide. To date the underlying cause remains unclear and no drug has been accredited for first-line therapy. VCAM-1 has been reported to play a pivotal role in establishing ECRS. Other authors have reported that inflammatory cytokines may mediate changes in the underlying epithelium in the sinuses through hepatocyte growth factor HGF. In our study, the effect of VCAM-1 on HGF levels was investigated. MATERIALS AND METHODS: ECRS cell cultures were incubated with VCAM-1 and HGF levels were determined after 16, 24, 48 and 72 hours. RT-PCR was enrolled to depict the HGF-RNA levels. RESULTS: Sixteen hours of incubation showed 28.5 pg/ml HGF, whereas in the control 16.3 pg/ml was detectable. After 24 and 36 hours, 37 pg/ml and 43.5 pg/ml HGF were measured in the incubated cell cultures, respectively; 72 hours of incubation with VCAM-1 resulted in 50.6 pg/ml HGF, whereas 23.5 pg/ml was determined in the controls. The RT-PCR for HGF also showed increased concentration in the incubated cells after 72 hours. CONCLUSION: VCAM-1 induced an increase in levels of HGF in the ECRS cell cultures. The rising transcriptional activity was demonstrated by means of RT-PCR. The levels of HGF were within physiological ranges, suggesting that a misbalance between HGF and VCAM-1 resulted in the establishment of ECRS. Further experiments are necessary to reveal the role of HGF in the development of ECRS. This is the first report about the effect of VCAM-1 on growth factors in ECRS cell culture.

Otoplasty - techniques, characteristics and risks.

The protruding ear as a minor ear abnormality is found in approx. 5% of the German population and may give rise to serious emotional problems in children and also in adults. In general, the procedure used for the surgical correction of protruding ears (otoplasty) is a combination of incision, scoring and suture techniques. The choice of the surgical procedure is based on the severity of the ear abnormality and the individual characteristics of the auricular cartilage. In children up to the age of ten years, a soft, elastic or easily pliable auricular cartilage is often still present. In this situation, gentle suture techniques, such as a suturing technique described by Mustardé, are frequently enough to achieve a cosmetically good and lasting result. In adults, the auricular cartilage has already become stiff. Therefore, a combination of incision, scoring and suture techniques is usually required. Apart from reducing the cephaloauricular angle to 15-20°, emphasis on the antihelical fold and a smooth rim of the helix without interruption of the contour are desirable outcomes of this operation. Occasionally, surgical fixation (lobulopexy) may be required to treat protruding lobules or, in rare cases, an additional conchal reduction may become necessary in cases of conchal hyperplasia. Since postoperative complications can often result in severe auricular deformities, as a matter of principle, each ear should be analysed individually regarding its problem areas, and the surgical approach that causes the least injury to the cartilage should be used.

Tissue engineering of autologous cartilage grafts in three-dimensional in vitro macroaggregate culture system.

In the field of tissue engineering, techniques have been described to generate cartilage tissue with isolated chondrocytes and bioresorbable or nonbioresorbable biomaterials serving as three-dimensional cell carriers. In spite of successful cartilage engineering, problems of uneven degradation of biomaterial, and unforeseeable cell-biomaterial interactions remain. This study represents a novel technique to engineer cartilage by an in vitro macroaggregate culture system without the use of biomaterials. Human nasoseptal or auricular chondrocytes were enzymatically isolated and amplified in conventional monolayer culture before the cells were seeded into a cell culture insert with a track-etched membrane and cultured in vitro for 3 weeks. The new cartilage formed within the in vitro macroaggregates was analyzed by histology (toluidine blue, von Kossa-safranin O staining), and immunohistochemistry (collagen types I, II, V, VI, and X and elastin). The total glycosaminoglycan (GAG) content of native and engineered auricular as well as nasal cartilage was assayed colorimetrically in a safranin O assay. The biomechanical properties of engineered cartilage were determined by biphasic indentation assay. After 3 weeks of in vitro culture, nasoseptal and auricular chondrocytes synthesized new cartilage with the typical appearance of hyaline nasal cartilage and elastic auricular cartilage. Immunohistochemical staining of cartilage samples showed a characteristic pattern of staining for collagen antibodies that varied in location and intensity. In all samples, intense staining for cartilage-specific collagen types I, II, and X was observed. By the use of von Kossa-safranin O staining a few positive patches-a possible sign of beginning mineralization within the engineered cartilages-were detected. The unique pattern for nasoseptal cartilage is intense staining for type V collagen, whereas auricular cartilage is only weakly positive for collagen types V and VI. Engineered nasal and auricular macroaggregates were negative for anti-elastin antibody (interterritorially). The measurement of total GAG content demonstrated higher GAG content for reformed nasoseptal cartilage compared with elastic auricular cartilage. However, the total GAG content of engineered macroaggregates was lower than that of native cartilage. In spite of the mechanical stability of the auricular macroaggregates, there was no equilibrium of indentation. The histomorphological and immunohistochemical results demonstrate successful cartilage engineering without the use of biomaterials, and identify characteristics unique to hyaline as well as elastic cartilage. The GAG content of engineered cartilage was lower than in native cartilage and the biomechanical properties were not determinable by indentation assay. This study illustrates a novel in vitro macroaggregate culture system as a promising technique for tissue engineering of cartilage grafts. Further long-term in vitro and in vivo studies must be done before this method can be applied to reconstructive surgery of the nose or auricle.

Immunochemical and mechanical characterization of cartilage subtypes in rabbit.

Cartilage is categorized into three general subgroups, hyaline, elastic, and fibrocartilage, based primarily on morphologic criteria and secondarily on collagen (Types I and II) and elastin content. To more precisely define the different cartilage subtypes, rabbit cartilage isolated from joint, nose, auricle, epiglottis, and meniscus was characterized by immunohistochemical (IHC) localization of elastin and of collagen Types I, II, V, VI, and X, by biochemical analysis of total glycosaminoglycan (GAG) content, and by biomechanical indentation assay. Toluidine blue staining and safranin-O staining were used for morphological assessment of the cartilage subtypes. IHC staining of the cartilage samples showed a characteristic pattern of staining for the collagen antibodies that varied in both location and intensity. Auricular cartilage is discriminated from other subtypes by interterritorial elastin staining and no staining for Type VI collagen. Epiglottal cartilage is characterized by positive elastin staining and intense staining for Type VI collagen. The unique pattern for nasal cartilage is intense staining for Type V collagen and collagen X, whereas articular cartilage is negative for elastin (interterritorially) and only weakly positive for collagen Types V and VI. Meniscal cartilage shows the greatest intensity of staining for Type I collagen, weak staining for collagens V and VI, and no staining with antibody to collagen Type X. Matching cartilage samples were categorized by total GAG content, which showed increasing total GAG content from elastic cartilage (auricle, epiglottis) to fibrocartilage (meniscus) to hyaline cartilage (nose, knee joint). Analysis of aggregate modulus showed nasal and auricular cartilage to have the greatest stiffness, epiglottal and meniscal tissue the lowest, and articular cartilage intermediate. This study illustrates the differences and identifies unique characteristics of the different cartilage subtypes in rabbits. The results provide a baseline of data for generating and evaluating engineered repair cartilage tissue synthesized in vitro or for post-implantation analysis.

The characterisation of human respiratory epithelial cells cultured on resorbable scaffolds: first steps towards a tissue engineered tracheal replacement.

In this study we have used lectin histochemistry and scanning electron microscopy (SEM) to assess the growth and characterise the differentiation of human respiratory epithelial cells (REC) cultured on two biomaterial scaffolds. The first scaffold, based on a hyaluronic acid derivative, was observed to be non-adhesive for REC. This lack of adhesion was found to be unrelated to the presence of the hyaluronic acid binding domain on the surface of isolated REC. The other scaffold, consisting of equine collagen. was observed to encourage REC spreading and adhesion. Positive Ulex Europaeus agglutinin (UEA) lectin staining of this preparation indicated the presence of ciliated REC on the scaffold surface. However, the marked decrease in peanut agglutinin (PNA) positive staining, relative to that of control cultures and native tissue, indicates a dedifferentiation of the secretory cells of the REC monolayer. SEM analysis of REC cultured on the collagen scaffold confirmed the presence of ciliated cells thereby validating the UEA positive staining. The presence of both established and developing cilia was also verified. This study indicates that collagen biomaterials are appropriate for the tissue engineering of REC. Furthermore, that UEA and PNA staining is a useful tool in the characterisation of cells cultured on biomaterials, therefore helpful in identifying biomaterials that are suitable for specific tissue engineering purposes.