Non-equivalence of antibiotic generic drugs and risk for intensive care patients

Background: The underlying axiom in applying generic drugs is the equivalence of their active ingredient with the (usually more expensive) innovator product, an all-embracing statement with the insidious result that physicians assume that the generic products have been subjected to the same rigorous testing regimens as the brand-name products. The present paper presents novel experimental data on an investigator-blinded comparison between the innovator imipenem antibiotic, and a number of its generics. Methods: Particulate matter contamination of each group was visualized by means of a membrane filter method. Functional studies in an animal model–the dorsal skinfold chamber technique in mice-designed to simulate the state of microcirculatory dysfunction in intensive care patients was performed, in order to assess the influence of the particulate matter of each group on the functional capillary density of the striated skin muscle, after their intravenous injection. Results: The results showed massive particulate contamination of the generics, in a size range relevant for impacting the microcirculation. The particulate contamination contributed in some generic groups to a significant shutdown of tissue perfusion. Conclusion: The presented data underscore the need to raise the regulatory barriers for the entry of generics to the market, well beyond the simplistic proof of “bioequivalence”, which in no measure deals with the essential questions of quality and patient safety. If generics are used, they should be tested by a filter technique and optical microscopy, to ensure the absence especially of small particulate contaminants and their purity

Implantation of silicon dioxide-based nanocrystalline hydroxyapatite and pure phase beta-tricalciumphosphate bone substitute granules in caprine muscle tissue does not induce new bone formation

Background: Osteoinductive bone substitutes are defined by their ability to induce new bone formation even at heterotopic implantation sites. The present study was designed to analyze the potential osteoinductivity of two different bone substitute materials in caprine muscle tissue. Materials and methods: One gram each of either a porous beta-tricalcium phosphate (β-TCP) or an hydroxyapatite/silicon dioxide (HA/SiO2)-based nanocrystalline bone substitute material was implanted in several muscle pouches of goats. The biomaterials were explanted at 29, 91 and 181 days after implantation. Conventional histology and special histochemical stains were performed to detect osteoblast precursor cells as well as mineralized and unmineralized bone matrix. Results: Both materials underwent cellular degradation in which tartrate-resistant acid phosphatase (TRAP)-positive osteoclast-like cells and TRAP-negative multinucleated giant cells were involved. The ß-TCP was completely resorbed within the observation period, whereas some granules of the HA-groups were still detectable after 180 days. Neither osteoblasts, osteoblast precursor cells nor extracellular bone matrix were found within the implantation bed of any of the analyzed biomaterials at any of the observed time points. Conclusions: This study showed that ß-TCP underwent a faster degradation than the HA-based material. The lack of osteoinductivity for both materials might be due to their granular shape, as osteoinductivity in goat muscle has been mainly attributed to cylindrical or disc-shaped bone substitute materials. This hypothesis however requires further investigation to systematically analyze various materials with comparable characteristics in the same experimental setting

Multiwell three-dimensional systems enable in vivo screening of immune reactions to biomaterials:a new strategy toward translational biomaterial research

In vivo experiments are accompanied by ethical issues, including sacrificing a large number of animals as well as large costs. A new in vivo 3D screening system was developed to reduce the number of required animals without compromising the results. The present pilot study examined a multiwell array system in combination with three different collagen-based biomaterials (A, B and C) using subcutaneous implantation for 10 days and histological and histomorphometrical evaluations. The tissue reaction towards the device itself was dominated by mononuclear cells. However, three independent biomaterial-specific tissue reactions were observed in three chambers. The results showed a mononuclear cell-based tissue reaction in one chamber (A) and foreign body reaction by multinucleated giant cells in the other two chambers (B and C). Statistical analysis showed a significantly higher number of multinucleated giant cells in cases B and C than in case A (A vs. B; ***P[GRAPHICS].</p

Osteocalcin, Azan and Toluidine blue staining in fibrous dysplasia and ossifying fibroma of the jaws

Background: Fibrous dysplasia (FD) and ossifying fibroma (OF) are fibro-osseous lesions (FOLs) having several overlaps that may make final diagnosis difficult by hematoxylin and eosin (H/E) alone.Aim: This study seeks to detect any association between Azan and Toluidine blue staining as compared with osteocalcin in FD and OF diagnosis.Methods: Forty formalin fixed paraffin embedded (FFPE) blocks of FD and OF were prepared for Azan, Toluidine blue and osteocalcin staining. Brown staining of calcified structures was considered as positive for osteocalcin. Scoring for Azan and Toluidine blue was evaluated based on intensity and localization. Level of agreement of original and revised diagnosis was determined.Results: Six (40%) of 15 FD were corroborated by osteocalcin. Eight cases initially diagnosed as OF were revised to FD. There were 25 OF according to H/E, and 17 (68%) were validated by osteocalcin. Measure of agreement between histology and immunohistochemistry was 0.081; p = .608. Eleven (42.3%) OF expressed strong toluidine blue staining of the intervening fibrous connective tissue stroma while only 2 (14.2%) FD showed similar staining, this difference was statistically significant [p = .001].Conclusions: Histomorphometric analysis with Toluidine blue may reduce diagnostic errors of OF and FD.Keywords: Osteocalcin, Azan, Toluidine blue, Fibrous dysplasia, Ossifying fibrom

Contribution of outgrowth endothelial cells from human peripheral blood on in vivo vascularization of bone tissue engineered constructs based on starch polycaprolactone scaffolds

In the present study we assessed the potential of human outgrowth endothelial cells (OEC), a subpopulation within endothelial progenitor cell cultures, to support the vascularization of a complex tissue engineered construct for bone. OEC cultured on starch polycaprolactone fiber meshes (SPCL) in monoculture retained their endothelial functionality and responded to angiogenic stimulation by VEGF (vascular endothelial growth factor) in fibrin gel-assays in vitro. Co-culture of OEC with human primary osteoblasts (pOB) on SPCL, induced an angiogenic activation of OEC towards microvessel-like structures achieved without additional supplementation with angiogenic growth factors. Effects of co-cultures with pOB on the vascularization process by OEC in vivo were tested by subcutaneous implantation of Matrigel! plugs containing both, OEC and pOB, and resulted in OEC-derived blood vessels integrated into the host tissue and anastomosed to the vascular supply. In addition, morphometric analysis of the vascularization process by OEC indicated a better performance of OEC in the co-cultures with primary osteoblasts compared to monocultures of OEC. The contribution of OEC to vascular structures and the beneficial effect of the co-culture with primary human osteoblasts on the vascularization in vivo was additionally proven by subcutaneous implantation of pre-cellularized and pre-cultured SPCL constructs. OEC contributed to the vascular structures, by generating autogenic vessels or by incorporation into chimeric vessels consisting of both, human and mouse endothelial cells. The current data highlight the vasculogenic potential of OEC for bone tissue engineering applications and indicate a beneficial influence of constructs including both osteoblasts and endothelial cells for vascularization strategies.The authors would like to thank B. Malenica, C. Braun, L. Meyer, K. Molter, M. Muller. J. Alonso-Monje for their excellent technical assistance. This work was financially supported by grants from the European commission (HIPPOCRATES N degrees NMP3-CT-2003-505758; EXPERTISSUES Contract nr.: 500283-2) and BMBF-Grant for German-Chinese Cooperation in Regenerative Medicine (grant number 0315033)

Variant Purification of an Allogeneic Bone Block

Svrha: Ovaj kratak tekst izvještava o histološkoj analizi sastava komercijalno raspoloživih alogenih koštanih blokova Maxgraft®. Materijali i metode: Na temelju objavljenih histoloških metoda prazni uzorci alogenih koštanih blokova Maxgraft® dekalcificirani su, dehidrirani i uloženi u parafin prije histološkog i histokemijskog bojenja. Nakon toga na prerezima su se procjenjivala obilježja materijala, poput strukture koštanoga matriksa i druge komponente, uključujući kolagen ili stanice/stanične ostatke. Rezultati: Uočeno je da ovi koštani blokovi imaju trabekularnu strukturu s lamelarnom podorganizacijom. Dodatno su nađeni i stanični ostatci unutar lakuna osteocita i na vanjskim površinama trabekula zajedno s ostatcima intertrabekularnog masnog i vezivnog tkiva, te kolagene strukture, vezivno-tkivne stanice i stanični ostatci. Zaključak: U skladu s dosadašnjim istraživanjima, podatci iz ovoga teksta pokazuju da neke od certificiranih tehnika pročišćavanja ne omogućuju proizvodnju alogenog materijala bez organskih stanica i tkivnih komponenata.Objective: This short communication reports on a histological analysis of the composition of the commercially available Maxgraft® allogeneic bone block. Materials and Methods: Based on previously published, easily applicable histological methods, blanc samples of the Maxgraft® allogeneic bone block have been decalcified, dehydrated and embedded in paraffin before histological and histochemical staining. Afterwards, the slides were evaluated for their material characteristics, such as the bone matrix structure and other components, including collagen or cells/cell remnants. Results: The results show that this bone block exhibits a trabecular structure with lamellar sub-organization. Additionally, cellular remnants within the osteocyte lacunae and at the outer trabecular surfaces reside together with remnants of the former inter-trabecular fatty and connective tissue, i.e., collagenous structures and connective tissue cells or cell remnants. Conclusion: Consistent with a previous study on this topic, the data presented here demonstrate that some of the certified purification techniques might not allow for the production of allogeneic materials free of organic cell and tissue components

KARAPANDZIC FLAP FOR RECONSTRUCTION OF LOWER LIP IN A 18-MONTH OLD BOY WITH CONGENITAL AGAMMAGLOBULINEMIA AND ECTHYMA GANGRENOSUM. CASE REPORT

The reconstruction of lower lip in children is extremely rare and challenging procedure. The etiology in literature reveals trauma and infection. An 18-month boy was admitted with sepsis and pneumonia. Laboratory tests revealed congenital agammaglobulinemia. Necrosis of lower lip developed and was diagnosed as ecthyma gangrenosum. Blood culture was positive for Pseudomonas aeruginosa. Multiple abscess formations were found in abdominal wall and gluteal region and were treated by incisions. After spontaneous demarcation of necrotic tissue in lower lip the Karapandzic flap technique was used for reconstruction. Karapandzic flap can be used as optimal method for reconstruction of lower lip in children with satisfactory functional and aesthetic results.Key words: Karapandzic flap, ecthyma gangrenosum, reconstructio

In vivo Implantation of a Bovine-Derived Collagen Membrane Leads to Changes in the Physiological Cellular Pattern of Wound Healing by the Induction of Multinucleated Giant Cells: An Adverse Reaction?

The present study evaluated the tissue response toward a resorbable collagen membrane derived from bovine achilles tendon (test group) in comparison to physiological wound healing (control group). After subcutaneous implantation in Wistar rats over 30 days, histochemical and immunohistochemical methods elucidated the cellular inflammatory response, vascularization pattern, membrane protein and cell absorbance capacity. After 30 days, the test-group induced two different inflammatory patterns. On the membrane surface, multinucleated giant cells (MNGCs) were formed after the accumulation of CD-68-positive cells (macrophages), whereas only mononuclear cells (MNCs) were found within the membrane central region. Peri-implant vascularization was significantly enhanced after the formation of MNGCs. No vessels were found within the central region of the membrane. Physiological wound healing revealed no MNGCs at any time point. These dynamic changes in the cellular reaction and vascularization within the test-group are related typical indications of a foreign body reaction. Due to the membrane-specific porosity, mononuclear cells migrated into the central region, and the membrane maintained its integrity over 30 days by showing no breakdown or disintegration. The ex vivo investigation analyzed the interaction between the membrane and a blood concentrate system, liquid platelet-rich fibrin (liquid PRF), derived from human peripheral blood and consisting of platelets, leukocytes and fibrin. PRF penetrated the membrane after just 15 min. The data question the role of biomaterial-induced MNGCs as a pathological reaction and whether this is acceptable to trigger vascularization or should be considered as an adverse reaction. Therefore, further pre-clinical and clinical studies are needed to identify the types of MNGCs that are induced by clinically approved biomaterials

Spontaneous In Vivo Chondrogenesis of Bone Marrow-Derived Mesenchymal Progenitor Cells by Blocking Vascular Endothelial Growth Factor Signaling

Chondrogenic differentiation of bone marrow-derived mesenchymal stromal/stem cells (MSCs) can be induced by presenting morphogenetic factors or soluble signals but typically suffers from limited efficiency, reproducibility across primary batches, and maintenance of phenotypic stability. Considering the avascular and hypoxic milieu of articular cartilage, we hypothesized that sole inhibition of angiogenesis can provide physiological cues to direct in vivo differentiation of uncommitted MSCs to stable cartilage formation. Human MSCs were retrovirally transduced to express a decoy soluble vascular endothelial growth factor (VEGF) receptor-2 (sFlk1), which efficiently sequesters endogenous VEGF in vivo, seeded on collagen sponges and immediately implanted ectopically in nude mice. Although naïve cells formed vascularized fibrous tissue, sFlk1-MSCs abolished vascular ingrowth into engineered constructs, which efficiently and reproducibly developed into hyaline cartilage. The generated cartilage was phenotypically stable and showed no sign of hypertrophic evolution up to 12 weeks. In vitro analyses indicated that spontaneous chondrogenic differentiation by blockade of angiogenesis was related to the generation of a hypoxic environment, in turn activating the transforming growth factor-β pathway. These findings suggest that VEGF blockade is a robust strategy to enhance cartilage repair by endogenous or grafted mesenchymal progenitors. This article outlines the general paradigm of controlling the fate of implanted stem/progenitor cells by engineering their ability to establish specific microenvironmental conditions rather than directly providing individual morphogenic cues.; Chondrogenic differentiation of mesenchymal stromal/stem cells (MSCs) is typically targeted by morphogen delivery, which is often associated with limited efficiency, stability, and robustness. This article proposes a strategy to engineer MSCs with the capacity to establish specific microenvironmental conditions, supporting their own targeted differentiation program. Sole blockade of angiogenesis mediated by transduction for sFlk-1, without delivery of additional morphogens, is sufficient for inducing MSC chondrogenic differentiation. The findings represent a relevant step forward in the field because the method allowed reducing interdonor variability in MSC differentiation efficiency and, importantly, onset of a stable, nonhypertrophic chondrocyte phenotype

Bovine pericardium based non-cross linked collagen matrix for successful root coverage, a clinical study in human

Introduction: The aim of this study was to clinically assess the capacity of a novel bovine pericardium based, non-cross linked collagen matrix in root coverage. Methods: 62 gingival recessions of Miller class I or II were treated. The matrix was adapted underneath a coronal repositioned split thickness flap. Clinical values were assessed at baseline and after six months. Results: The mean recession in each patient was 2.2 mm at baseline. 6 Months after surgery 86.7% of the exposed root surfaces were covered. On average 0,3 mm of recession remained. The clinical attachment level changed from 3.5 ± 1.3 mm to 1,8 ( ± 0,7) mm during the observational time period. No statistically significant difference was found in the difference of probing depth. An increase in the width of gingiva was significant. With a baseline value of 1.5 ± 0.9 mm an improvement of 2.4 ± 0.8 mm after six month could be observed. 40 out of 62 recessions were considered a thin biotype at baseline. After 6 months all 62 sites were assessed thick. Conclusions: The results demonstrate the capacity of the bovine pericardium based non-cross linked collagen matrix for successful root coverage. This material was able to enhance gingival thickness and the width of keratinized gingiva. The percentage of root coverage achieved thereby is comparable to existing techniques. This method might contribute to an increase of patient's comfort and an enhanced aesthetical outcome