Infections in primary total ankle replacement: Anterior approach versus lateral transfibular approach

Background

Total ankle replacement (TAR) represents an alternative to fusion for the treatment of end-stage ankle osteoarthritis. The aim of the present study was to retrospectively assess the frequency of infections between TARs with anterior and lateral transfibular approach at 12-months follow-up.

Nutritional-inflammation status and resistance to erythropoietin therapy in haemodialysis patients.

BACKGROUND: Chronic kidney disease patients who are resistant to erythropoietin (EPO) treatment may suffer from malnutrition and/or inflammation. METHODS: In a cross-sectional study of haemodialysis patients, we investigated the relationship between the natural logarithm of the weekly EPO dose normalized for post-dialysis body weight and outcome measures of nutrition and/or inflammation [BMI, albumin and C reactive protein (CRP)] by means of multiple linear regression analysis. On the basis of the decile distribution of weekly EPO doses, we also evaluated four groups of patients: untreated, hyper-responders, normo-responders and hypo-responders. RESULTS: Six hundred and seventy-seven adult haemodialysis patients were recruited from five Italian centres. BMI and albumin were lower in the hypo-responders than in the other groups (21.3+/-3.8 vs 24.4+/-4.7 kg/m(2), P<0.001; and 3.8+/-0.6 vs 4.1+/-0.4 g/dl, P<0.001), whereas the median CRP level was higher (1.9 vs 0.8 mg/dl, P = 0.004). The median weekly EPO dose ranged from 30 IU/kg/week in the hyper-responsive group to 263 IU/kg/week in the hypo-responsive group. Transferrin saturation linearly decreased from the hyper- to hypo-responsive group (37+/-15 to 25+/-10%, P = 0.003), without any differences in transferrin levels. Ferritin levels were lower in the hypo-responsive than in the other patients (median 318 vs 445 ng/ml, P = 0.01). At multiple linear regression analysis, haemoglobin, BMI, albumin, CRP and serum iron levels were independently associated with the natural logarithm of the weekly EPO dose (R(2) = 0.22). CONCLUSIONS: Our findings support a clear association between EPO responsiveness and nutritional and inflammation variables in haemodialysis patients; iron deficiency is still a major cause of hypo-responsiveness.     

Turbulent stress measurements downstream of three bileaflet heart valve designs in pigs

Objective: Mechanical heart valves can cause thromboembolic complications, possibly due to abnormal flow patterns that produce turbulence downstream of the valve. The objective of this study was to investigate whether three different bileaflet valve designs would exhibit clinically relevant differences in downstream turbulent stresses. Methods: Three bileaflet mechanical heart valves (Medtronic Advantage^®, CarboMedics© Orbis™ Universal and St. Jude Medical^® Standard) were implanted into 19 female 90 kg pigs. Blood velocity was measured during open chest conditions in the cross sectional area downstream of the valves with 10 MHz ultrasonic probes connected to a modified Alfred^® Pulsed Doppler equipment. As a measure of turbulence, Reynolds normal stress (RNS) was calculated at three different cardiac output ranges (3–4, 4.5–5.5, 6–7 L/min). Results: Data from 12 animals were obtained. RNS correlated with increasing cardiac outputs. The highest instantaneous RNS observed in these experiments was 47 N/m², and the mean RNS taken spatially over the cross sectional area of the aorta during systole was between 3 N/m² and 15 N/m². In none of the cardiac output ranges RNS values exceeded the lower critical limit for erythrocyte or thrombocyte damage for any of the valve designs. Conclusions: Reynolds normal stress values were below 100 N/m² for all three valve designs and the difference in design was not reflected in generation of turbulence. Hence, it is unlikely that any of the valve designs causes flow induced damage to platelets or erythrocytes.     

Activation of the langendorff perfused rat heart depolarized by increased external potassium concentration

Myocardial activation under depolarized conditions was studied in spontaneously beating Langendorff perfused hearts from albino rats. Depolarization was obtained by increasing external potassium concentration in steps (5.4, 7.4, 10, 10.5, 11 and 11.5 mM) in the perfusing solution with or without adrenaline (Adr). Left ventricle isovolumic systolic pressure and coronary flow did not change as external potassium increased, albeit being larger with Adr in the perfusing solution. Atrial and ventricular rates decreased, the latter showing a larger decline. The same behaviour was displayed by perfused hearts, with higher rates being developed by the group with Adr. PR interval and QRS complex duration increased as a function of external potassium. PR intervals were the same in both groups but QRS duration was larger in the Adr group, indicating that AV conduction was not changed in presence of Adr but intraventricular conduction was delayed in that situation. It was also observed that in the great majority of perfused hearts, differing from isolated preparations, ventricular mechanical activity ceased at around 11.5 mM external potassium.