Influence of micro- and nano-hydroxyapatite coatings on the osteointegration of metallic (Ti6Al4 V) and bioabsorbable interference screws: an in vivo study.

The purpose of this study is to show and compare the fixation and osteointegration capability of metallic and bioabsorbable interference screws. For this, 8×20-mm interference screws were implanted into the bone tunnel in the proximal tibial metaphysis of sheep. The nano- (25 nm±0.8) and microscale (25 µm±0.5) hydroxyapatite were both dip-coated on Ti6Al4 V interference screws via an in vivo study. After the initial 12 weeks of postoperative, the pullout test, histopathology, X-ray diffraction and scanning electron microscopy examinations were performed. This multidisiplined work showed that the coated screws particularly those with nano-sized-HA coating and the bioabsorbable screws enhanced fixation and provided better stabilization, bone ingrowth and osteointegration than that of uncoated and microscale HA-coated screws. The bioabsorbable screws showed better histopathologic results.

Evaluation of 4 point-of-care units for the determination of blood l-lactate concentration in cattle.

BACKGROUND: Despite being used commonly in bovine medicine, information on reliability of point-of-care (POC) lactate meters is limited. OBJECTIVE: To determine the validity of 4 commercially available POC lactate meters in cattle. ANIMALS: Cattle with various diseases (n = 120). METHODS: Blood samples collected from the jugular vein were processed immediately on POC lactate meters. Plasma l-lactate concentration was measured by the enzymatic-colorimetric method (ELISA). Data were subjected to Friedman's test for comparison, Passing-Bablok regression and Bland-Altman plot analyses for reliability, and receiver operating characteristics analysis for sensitivity (Se) and specificity (Sp). RESULTS: The POC lactate meters were highly correlated with ELISA (r = 0.98-0.99) despite disagreements among units. When regressed on ELISA, blood l-lactate concentrations generated from Accutrend Plus and Lactate Pro were linear up to 16.6 and 15.7 mmol/L, respectively, whereas those generated from i-STAT and Lactate Scout were linear up to 19.5 and 19.7 mmol/L, respectively. All POC lactate meters had a Se of 100% with Sp of 95.7-98.6% at a plasma l-lactate cut-off concentration of 4 mmol/L. i-STAT had the best accuracy (99.0%) and precision (99.8%), the best linear fit (y = -0.13 + 1.04X) yielding the lowest bias (-6.6%) as well as the highest Se (100%) and Sp (98.6%). CONCLUSIONS AND CLINICAL IMPORTANCE: Despite high correlation with the reference method, dilution is needed for Accutrend Plus/Lactate Pro and i-STAT/Lactate Scout if concentrations >15 and 20 mmol/L, respectively. i-STAT provided the most accurate and precise results.

Influence of orthopaedic drilling parameters on temperature and histopathology of bovine tibia: an in vitro study.

Orthopaedic drilling operations without optimum operating parameters by surgeons may cause bone defects such as bone fracture, cracks, osteolysis and tissue loss around the drilling zone. For the sake of optimum drilling parameters, an in vitro study was performed by considering the bone mineral density, bone sex, drill tip angle, drill speed, drill force and feed-rate. The specimens were taken from the drilled sites of fresh male and female calf tibias. The temperature changes at the drill site were investigated throughout the statistical and histopathological analysis. It was observed that the temperature increased with an increasing drill speed and decreased with high feed-rates and applied drill forces. The drilling temperatures of the female bovine tibias were found to be higher than that of the male tibias and the drill speed was found to be a significant parameter on the maximum temperature. Moreover, the maximum temperature increased with an increasing drill tip angle and bone mineral density. Therefore the bone quality around the drill site was found to be worse than the bone samples exposed to low temperatures.

Simulation of a programmable pulser for phased array transducers.

We propose circuits for the implementation of a programmable pulser for phase array transducers. These provide digital control of pulse timing and firing, plus the possibility of manual setting of exciting pulse nature (simple or double), width and amplitude. Matching to the probe is thus optimized while programming enables adaptation to various types of transducers.

Lichen planus: review and update on pathogenesis.

Lichen planus (LP) is a common oral disorder which may represent the manifestation of a mucosal reaction to a variety of aetiological factors. Of the many immunological changes described in LP several may be epiphenomena although a cell-mediated immune response to unidentified antigens or antigenic changes clearly is involved. Associations with drugs or systemic disorders are well-defined in some patients but may, in others, be aleatoric. Finally, the prognosis of oral LP not only differs from that of cutaneous LP but there is little doubt that in a few instances LP is a premalignant condition.

Lichen planus and liver disease: how strong is the association?

One hundred and thirteen patients with histologically confirmed oral lichen planus, from three stomatology clinics, were examined for evidence of liver disease. No patient had clinical evidence of liver disease. Nine patients (7.9%) had a raised serum concentration of a single enzyme; 6 patients had raised gamma-glutamyl transpeptidase, 2 had raised alkaline phosphatase, and 1 had raised aspartate transaminase levels. No patient had serum auto-antibodies suggestive of primary biliary cirrhosis or chronic active hepatitis. Most patients presenting with oral lichen planus are unlikely to have liver disease.