Poly-Alanine-ε-Caprolacton-Methacrylate as Scaffold Material with Tuneable Biomechanical Properties for Osteochondral Implants.

An aging population and injury-related damage of the bone substance lead to an increasing need of innovative materials for the regeneration of osteochondral defects. Biodegradable polymers form the basis for suitable artificial implants intended for bone replacement or bone augmentation. The great advantage of these structures is the site-specific implant design, which leads to a considerable improvement in patient outcomes and significantly reduced post-operative regeneration times. Thus, biomechanical and biochemical parameters as well as the rate of degradation can be set by the selection of the polymer system and the processing technology. Within this study, we developed a polymer platform based on the amino acid Alanine and ε-Caprolacton for use as raw material for osteochondral implants. The biomechanical and degradation properties of these Poly-(Alanine-co-ε-Caprolacton)-Methacrylate (ACM) copolymers can be adjusted by changing the ratio of the monomers. Fabrication of artificial structures for musculo-skeletal tissue engineering was done by Two-Photon-Polymerization (2PP), which represents an innovative technique for generating defined scaffolds with tailor-made mechanical and structural properties. Here we show the synthesis, physicochemical characterization, as well as first results for structuring ACM using 2PP technology. The data demonstrate the high potential of ACM copolymers as precursors for the fabrication of biomimetic implants for bone-cartilage reconstruction.

Evaluation of reticulocyte hemoglobin content (RET-He) in the diagnosis of iron-deficient erythropoiesis in dogs.

BACKGROUND: Reticulocyte hemoglobin content provided by the Siemens ADVIA (CHr) is an established marker of iron deficiency. The IDEXX ProCyte Dx hematology analyzer now provides a similar variable, reticulocyte hemoglobin equivalent (RET-He). OBJECTIVES: The objective was to evaluate RET-He and its diagnostic utility in dogs, and to calculate a cutoff value for diagnosing iron-deficient erythropoiesis (IDE). Furthermore, the prevalence of RET-He values below this cutoff value was established. METHODS: One hundred and seventy-one CBCs of healthy dogs were used to establish a RI. Stability of RET-He was evaluated by repeated measurements over 48 hours (n = 10). The 25-run coefficient of variation (CV) was calculated, and correlation and bias between measurements of RET-He and CHr were assessed (n = 190). A cutoff value for diagnosing IDE was calculated. The utility of RET-He in the detection of IDE was evaluated in 123 dogs. The prevalence of low RET-He values was assessed retrospectively in a multicenter study (2012-2014) under participation of 7 veterinary clinics. RESULTS: Reticulocyte hemoglobin equivalent with an RI of 22.2 to 28.6 pg was statistically stable over 48 hours (P = .10). The CV was 1.8%. A fair correlation (ρ = 0.74) between RET-He and CHr with a small bias of -0.6 pg was found. The cutoff value for diagnosing IDE was 20.9 pg (sensitivity: 85%; specificity: 99%). The prevalence of RET-He values below 20.9 pg was 10.3% (1084/10,553 dogs). CONCLUSIONS: RET-He on the ProCyte Dx is a precise screening tool in dogs to detect iron-deficient erythropoiesis.

Canine reticulocyte hemoglobin content (RET-He) in different types of iron-deficient erythropoiesis.

BACKGROUND: Reticulocyte hemoglobin content (RET-He) is a diagnostic marker for iron deficiency (ID) in people and dogs. OBJECTIVES: The aim of our study was to evaluate the clinical utility of RET-He in the diagnosis of different causes of iron-deficient erythropoiesis (IDE). METHODS: Canine CBCs were separated into 2 groups according to RET-He values, < 20.9 pg or ≥ 20.9 pg. Erythrocyte and reticulocyte variables were compared between dogs with decreased and normal RET-He values. Additional data for a subgroup of dogs were collected, and dogs with low RET-He values were categorized as having ID, inflammatory disorders (INFL), portosystemic shunt (PSS), miscellaneous diseases (MISC), or combinations of these diseases (ID+INFL, ID+PSS). Hematologic variables were compared between dogs of the different disease groups. RESULTS: Overall, 10.3% (1084/10,553) of canine CBCs showed decreased RET-He values. Significant differences between dogs with decreased and normal RET-He values were found for all erythrocyte and reticulocyte variables. The majority (68.9%, 747/1084) of dogs with low RET-He values was anemic; 28.9% (216/747) of those anemic dogs had microcytosis and hypochromasia. In the subgroup of dogs, 8.9% (205/2306) had low RET-He values. According to their diagnosed diseases, anemic dogs (138/205) could be categorized as ID (17/138; 12.3%), INFL (16/138; 11.6%), PSS (30/138; 21.7%), ID+INFL (63/138; 45.7%), ID+PSS (8/138; 5.8%), and MISC (4/138; 2.9%). Distribution in nonanemic dogs (67/205) was similar, except for a lower number of dogs with PSS. CONCLUSIONS: Low RET-He values indicate IDE even in dogs with other CBC variables within the RIs.