Pentosidine in chronic hemodialysis patients: relation with arteriovenous fistula morphology and function

International Urology and Nephrology - It has been suggested that advanced glycation end products (AGEs) are involved in atherogenesis, vascular calcification and remodeling, including neointimal...     

Autologous mesenchymal stem cells applied on the pressure ulcers had produced a surprising outcome in a severe case of neuromyelitis optica

Recent studies provided evidence that mesenchymal stem cells (MSCs) have regenerative potential in cutaneous repair and profound immunomodulatory properties making them a candidate for therapy of neuroimmunologic diseases. Neuromyelitis optica (NMO) is an autoimmune, demyelinating central nervous system disorder characterized by a longitudinally extensive spinal cord lesion. A 46-year-old male diagnosed with NMO had relapses with paraplegia despite treatment and developed two stage IV pressure ulcers (PUs) on his legs. The patient consented for local application of autologous MSCs on PUs. MSCs isolated from the patient''s bone marrow aspirate were multiplied in vitro during three passages and embedded in a tridimensional collagen-rich matrix which was applied on the PUs. Eight days after MSCs application the patient showed a progressive healing of PUs and improvement of disability. Two months later the patient was able to walk 20 m with bilateral assistance and one year later he started to walk without assistance. For 76 months the patient had no relapse and no adverse event was reported. The original method of local application of autologous BM-MSCs contributed to healing of PUs. For 6 years the patient was free of relapses and showed an improvement of disability. The association of cutaneous repair, sustained remission of NMO and improvement of disability might be explained by a promotion/optimization of recovery mechanisms in the central nervous system even if alternative hypothesis should be considered. Further studies are needed to assess the safety and efficacy of mesenchymal stem cells in NMO treatment.     

Prospects for microtechnology and nanotechnology in bioengineering of replacement microvessels

CONTEXT: Due to its anticipated curative potential, therapeutic angiogenesis recently became a major preoccupation for the biomedical research community. Most of the related work reported to date employs either biochemical or genetic tools. OBJECTIVE: To identify opportunities for application of the current developments in microtechnology and nanotechnology to the field of therapeutic angiogenesis. DATA SOURCES: Survey of recent English-language literature on microvascular tissue engineering in the context of therapeutic angiogenesis. We include our results regarding the role played by microtopographical cues in the progression of angiogenesis, such as those produced during processing of the extracellular matrix by chronic inflammatory cells. CONCLUSION: While notable accomplishments have been identified in the field of tissue engineering of larger vessels, reports on purposeful assembly of microvascular structures with the ability to be transferred in vivo by implantation are still scarce. Under these circumstances, we suggest the development of a new class of implantable biomedical microdevices, that is, "angiogenesis assist devices" (or "angiochips"), and we indicate some of their conceivable applications.     

A deletion of a novel heat shock gene on the Y chromosome associated with azoospermia

Deletions of the Y chromosome are a significant cause of spermatogenic failure. Three major deletion intervals have been defined and termed AZFa, AZFb and AZFc. Here, we report an unusual case of a proximal AZFb deletion that includes the Y chromosome palindromic sequence P4 and a novel heat shock factor (HSFY). This deletion neither include the genes EIF1AY, RPS4Y2 nor copies of the RBMY1 genes. The individual presented with idiopathic azoospermia. We propose that deletions of the testis-specific HSFY gene family may be a cause of unexplained cases of idiopathic male infertility. This deletion would not have been detected using current protocols for Y chromosome microdeletion screens, therefore we recommend that current screening protocols be extended to include this region and other palindrome sequences that contain genes expressed specifically in the testis.     

Electroanalytical properties of a novel biosensor modified with zirconium alcoxide porous gels for the detection of acetaminophen

The development of composite electrodes for biosensors construction based on HRP and zirconium alcoxide film for acetaminophen detection and finally, acetaminophen determination in pharmaceutical products is described. The enzyme immobilization is performed by retention in a polyetilenimine and zirconium alcoxide porous gel film, technique that offers a good entrapping and in the mean times a "protective" environment for the biocomponent. The operation principle of the biosensor is based on monitoring the amperometric signal generated by reduction at the electrode surface of the enzymatically generated quinoneimine from acetaminophen. The resulting biosensor shows a linear response towards acetaminophen with a linear range of 1.96 x 10(-5)M and 2.55 x 10(-4)M and a limit of detection of 1.17 x 10(-7)M. The proposed biosensor shows long term stability and good reproducibility.     

New and Recovered Temporary Anchorage Devices,In Vitro Assessment of Structural and Surface Properties

The orthodontic miniscrew (TADs) is a device that is fixed into bone in the short term for the purpose of enhancing orthodontic anchorage. The aim of our study was to investigate the structural and surface properties of recovered TADs after orthodontic treatment, and compare them to new TADs. TADs (n = 15) from the same manufacturer (Absoanchor; Dentos, Daegu, Korea) were assessed; n = 10 were recovered from patients after orthodontic treatment and n = 5 were new. We performed electrochemical investigations, scanning electron microscopy (SEM) and microbiological analysis. Qualitative analysis on general electrochemical polarization revealed that the TADs retrieved from the patients provided much lower current densities in the passivity zone, and the oxidative processes taking place on their surface were of lower intensity. The surface morphologies of the tips of the retrieved mini-implants showed less sharp tips and smooth surfaces. Defects in the form of pores or cracks could be identified in both evaluated TAD groups. All retrieved TADs showed signs of biological materials (SEM analysis) and contamination on their surfaces. In conclusion, these results can assist orthodontists in comprehending the complexities of TAD behavior with respect to their design and structure.     

Identification of the cleavage site involved in production of plasma soluble Fc gamma receptor type III (CD16)

CD16 (Fcγ R type III) is a low-affinity IgG Fc receptor (R) that exists in two isoforms, a transmembrane FcγRIIIa expressed by NK cells and monocytes, and a phosphatidylinositol-linked FcγRIIIb expressed by neutrophils. A soluble form of CD16 (sCD16) circulates in plasma. The cleavage site and the nature of the enzyme(s) involved in production of sCD16 were investigated. Soluble CD16 was purified to apparent homogeneity from human serum by eight steps, including anion exchange and immunoaffinity chromatography. Serum sCD16 was sequenced at both ends, as well as a recombinant form of sCD16 used as control. N-terminal sequencing demonstrated that serum sCD16 originates from neutrophil FcγRIIIb and C-terminal sequencing suggested that the cleavage site is between Val 196 and Ser 197, close to the membrane anchor. Addition of a hydroxamate-based inhibitor of Zn²⁺ metalloproteinases (RU36156) led to a dramatic decrease of sCD16 production by phorbol 12-myristate 13-acetate-activated neutrophils, whereas inhibitors of serine proteinases had no significant effect, showing the metalloproteinase dependence of this cleavage process.