Metal ion-oxytetracycline pharmacokinetic interactions after oral co-administration in broiler chickens.

The influence of the composition of calcium (Ca(2+)), magnesium (Mg(2+)), and iron (Fe(3+)) ions in two concentration levels (low-500 mg/L of CaCl2, 125 mg/L of MgCl2, and 10 mg/L of FeCl3 and high-2,500 mg/L of CaCl2, 625 mg/L of MgCl2, and 50 mg/L of FeCl3) contained in water on the pharmacokinetics (PK) of oxytetracycline (OTC) was determined. OTC hydrochloride was administered at a dose of 25 mg/kg of body weight to broiler chickens divided into four groups of nine birds each, including 3 oral groups (in deionized water -control, in water with low ion concentration, and in water with high ion concentration) and 1 intravenous group. OTC concentrations in plasma were determined using liquid chromatography-tandem mass spectrometry, after which non-compartmental pharmacokinetic analysis was conducted.The absolute bioavailability of OTC in the group of birds exposed to higher ions concentration was reduced (8.68% ± 2.56) as compared to the control (13.71% ± 2.60). Additionally, in this group, decrease in PK parameters such as: area under the concentration-time curve from 0 to infinity (15.36 µg × h/mL ± 4.36), from 0 to t (14.78 µg × h/mL ± 4.37), area under the first moment of curve from 0 to t (107.54 µg × h/mL ± 36.48), and maximum plasma concentration (2.13 µg/mL ± 0.32) were also observed. It is noteworthy, all mentioned parameters demonstrated a downward trend with high correlation coefficient (P = 0.004, P = 0.002, P = 0.005, P = 0.004, P = 0.011, respectively), reflecting the influence of increasing concentrations of Ca(2+), Mg(2+), and Fe(3+) ions on the decreasing absorption rate of OTC.Based on the current research results, it can be assumed that high concentrations of several ions applied concomitantly are able to decrease the absorption of OTC from gastrointestinal tract in broiler chickens. This occurrence might impair the drug's clinical efficacy toward some pathogenic microorganisms. It implies that using OTC on a farm may require administration of higher doses than the routine one when infections are caused by less sensitive pathogens.

Human thoracic anatomy based on computed tomography for development of a totally implantable left ventricular assist system.

Human thoracic anatomy was studied using computed tomography (CT) for the development of a totally implantable electrohydraulic left ventricular system [Nimbus, Inc., and The Cleveland Clinic Foundation (CCF)]. To obtain statistical dimensional information for the chest wall, apex of the heart, and aorta, routine calibrated CT scans of 18 men and 17 women were analyzed. A special radiopaque vest was worn by the patient just prior to the scanning and X-ray procedures, so that each transverse scan could be assigned to a specific chest level after combination with a standard vertical referencing system set on the patient's radiogram. A polar coordinate system and direct measurement of transverse distances from the vertical column to points on the chest wall were employed to define collectively the shape and size of the intrathoracic surface of the chest wall. Locations of the aorta and apex were described by measuring their normalized distances from the midline and vertical column to the intrathoracic surface of the lateral and anterior chest wall. The radius of curvature of the intrathoracic wall lateral to the left ventricle was determined to be approximately 10.4 cm for the average adult male chest. The present CCF intrathoracic pump with this curvature fits fairly well in both the average and individual thoraxes of these adult males. The location of the aorta, particularly of the descending aorta, was used to determine the optimal outlet design. The most critical anatomical area was the apex location. For adult males, an average distance of 2.8 cm from the apex to the internal chest wall was found. Because of this small dimension, careful design of the inflow port is being performed to avoid anatomical mismatch.

Lateral recess syndrome: diagnosis and chiropractic management.

The Lateral Recess Syndrome (LRS) represents stenosis of the lateral subarticular gutter that will often lead to nerve root compression. The most common etiology is hypertrophy of the superior articular facets, associated with lumbar instability and arthrosis of the posterior joint complex. The diagnosis may be made clinically with a routine lumbosacral x-ray series, but is not definitive without the use of CT scanning. Recent studies indicate that spinal manipulation can provide relief and should be considered before surgical referral is made for decompression.