Conservative Surgical Treatment of Infected Ulceration of the First Metatarsophalangeal Joint With Osteomyelitis in Diabetic Patients.

Ulceration of the plantar aspect of the first metatarsophalangeal joint is a common localization in the diabetic foot. Conservative treatment of this lesion is a challenging problem, performed through the soft tissues and osseous debridement. The present study included a cohort of 28 patients affected by diabetes mellitus and a first ray lesion penetrating the bone. After surgical debridement with removal of the infected bone, we positioned antibiotic-loaded bone cement and stabilized the treated area with an external fixator. All patients with critical limb ischemia had their vascular disease treated before the procedure. The mean follow-up was 12.2 ± 6.9 months. Four patients developed a relapse of the ulceration after the procedure. In the postoperative period, 1 patient (3.57%) developed dehiscence of the surgical site and underwent a second procedure. In the follow-up period, 2 patients (7.14%) experienced bone cement dislocation. In 1 of these patients, a new ulceration was observed dorsally to the surgical site. The approach was surgical revision with bone cement replacement and stabilization with a new external fixator. In the other patient, given the absence of ulcerations, the cement was removed, and arthrodesis with internal stabilization using 2 cannulated screws was performed. One patient (3.57%), who had developed a relapse of ulceration after recurrent critical ischemia, underwent a percutaneous revascularization procedure and transmetatarsal amputation. During the follow-up period, no ulceration recurrences, transfer ulcerations, shoe fit problems, or gait abnormalities were detected in the other 24 patients. Our study presents the results of a technique requiring a 1-stage surgical approach to a relatively common problem, which is often difficult to solve.

Catalytically active bovine serum amine oxidase bound to fluorescent and magnetically drivable nanoparticles.

Novel superparamagnetic surface-active maghemite nanoparticles (SAMNs) characterized by a diameter of 10 ± 2 nm were modified with bovine serum amine oxidase, which used rhodamine B isothiocyanate (RITC) adduct as a fluorescent spacer-arm. A fluorescent and magnetically drivable adduct comprised of bovine serum copper-containing amine oxidase (SAMN-RITC-BSAO) that immobilized on the surface of specifically functionalized magnetic nanoparticles was developed. The multifunctional nanomaterial was characterized using transmission electron microscopy, infrared spectroscopy, mass spectrometry, and activity measurements. The results of this study demonstrated that bare magnetic nanoparticles form stable colloidal suspensions in aqueous solutions. The maximum binding capacity of bovine serum amine oxidase was approximately 6.4 mg g(-1) nanoparticles. The immobilization procedure reduced the catalytic activity of the native enzyme to 30% ± 10% and the Michaelis constant was increased by a factor of 2. We suggest that the SAMN-RITC-BSAO complex, characterized by a specific activity of 0.81 IU g(-1,) could be used in the presence of polyamines to create a fluorescent magnetically drivable H(2)O(2) and aldehydes-producing system. Selective tumor cell destruction is suggested as a potential future application of this system.

Charge binding of rhodamine derivative to OH- stabilized nanomaghemite: universal nanocarrier for construction of magnetofluorescent biosensors.

Superparamagnetic nanoparticles (20-40 nm) of maghemite, γ-Fe(2)O(3), with well-defined stoichiometric structure, are synthesized by the borohydride reduction of ferric chloride at an elevated temperature (100°C) followed by thermal treatment of the reaction product. Prepared maghemite nanoparticles reveal excellent colloidal stability for a long time without the necessity for any additional surface modification. These colloidal features are due to surface stabilizing OH(-) groups, which act as charge barriers preventing a particle aggregation and enabling a reversible binding of various oppositely charged organic substances. Such binding with rhodamine B isothiocyanate results in the fluorescent magnetic nanocarrier providing, at the same time, a spacer arm for covalent immobilization of other biosubstances including enzymes. In this work, we exploit this general applicability of the developed nanocarrier for covalent immobilization of glucose oxidase. This is the first reported example of magnetically drivable fluorescent nanocatalyst. The immobilized enzyme creates a 3-5 nm thick layer on the nanoparticle surface as proved by high-resolution transmission electron microscopy. This layer corresponds to 10 enzyme molecules, which are bound to the nanoparticle surface as found by the fluorimetric determination of flavin adenine dinucleotide. The developed magnetic fluorescent nanocatalyst, showing a rate constant of 32.7s(-1) toward glucose oxidation, can be used as a biosensor in various biochemical, biotechnological, and food chemistry applications. The presence of the nanocatalyst can be simply monitored by its fluorescence; moreover, it can be easily separated from the solution by an external magnetic field and repeatedly used without a loss of catalytic efficiency.

Preliminary kinetic characterization of a copper amine oxidase from rat liver mitochondria matrix.

Kinetic measurements of a novel copper-dependent amine oxidase, purified from rat liver mitochondria matrix, were carried out using various substrates in a large pH (5.6-10.2) and ionic strength range (5-200 mM), in order to study the docking of substrates to the enzyme and, as a consequence, to verify the physicochemical characteristics of the active site. Relatively small changes of V(max) values (approx. 2.5-folds) over the substrates tested, suggest that the rate determining step of the catalysis is only slightly affected by amine chemical structure. In contrast, the strong change of K(M) and k(c)/K(M) values (approx. two orders of magnitude) indicates electrostatic control of the docking process, since the changes of K(M) and k(c)/K(M) values appear due to the presence of positively charged groups in the substrate molecules. These results suggest the presence in the enzyme active site of two negatively charged amino acid residues which seem to interact with positively charged groups of the substrate molecules. Analogies and differences with bovine serum amine oxidase are also described.

Novel copper amine oxidase activity from rat liver mitochondria matrix.

Copper containing amine oxidases (Cu-AO) represent a heterogeneous class of enzymes classified as EC 1.4.3.6. The present study reports preliminary results on the presence of a novel amine oxidase activity in rat liver mitochondria lysates. Such enzymatic activity was found in the soluble mitochondrial fraction, obtained by simple osmotic shock. The mitochondrial amine oxidase was isolated by affinity chromatography on a newly synthesised spermine-Sepharose. SDS-PAGE showed a single band at about 60kDa. Upon chromatographic purification, the enzymatic activity was very labile. The crude enzyme activity was tested by spectrophotometric measurements, determining hydrogen peroxide production following oxidative deamination of different substrates, such as polyamines (spermine, spermidine, putrescine and cadaverine) and monoamines (dopamine and benzylamine). The activity, observed on polyamines and not on monoamines, was inhibited by semicarbazide and azide, but not by pargyline, clorgyline and l-deprenil. Enzyme specificity was tested on several diamines characterized by different carbon atom chain length in the range 2-6 carbon atoms. The highest activity was found with 1,2-diamino-ethane and the highest affinity with 1,5-diamino-pentane. The above reported results suggest the presence of a novel copper-dependent amine oxidase in liver mitochondria matrix.