Anomalous Activity Measurements of Creatine (Phospho) Kinase, CK-MB Isoenzyme in Indian Patients in the Diagnosis of Acute Coronary Syndrome

In the present study, the cause of suspected false-positive (anomalous) values for CK-MB activity, in Indian patients investigated for ACS. Total serum CK and CK-MB activity, serum Troponin I were measured and CK-MB as a percentage of the total CK activity (%CK-MB) calculated. CK-MB was also estimated using densitometry and CK-MB mass assay. Anomalous specimens were tested for the presence of CK isoenzymes. In 22 healthy subjects, 11 male and female, the %CK-MB ranged from 3.6 to 30.2. In 11 male patients, with proven ACS, the %CK-MB was from 4.0 to 17.5. The cut off for anomalous CK-MB activity values was set as >33.0%. In 35 patients with anomalies, total CK values ranged from 39 to 231 U/L, CK-MB from 30 to 161 U/L. Investigation of CK isoenzymes, showed 10 patients had a CK-BB band, 14 an intermediate band between CK-MM and CK-MB (macro-CK type 1), 7 had a cathodal band (macro-CK type 2), and 3 had a band intermediate between CK-MB and CK-BB. This later band does not seem to have been previously reported. Against the CK-MB mass assay, the activity assay showed no correlation, in 43 patients (19 M, 24 F), Pearson coefficient (R2) was 0.006. The CK-MB immunoinhibition assay is better described as measuring “non-CK-MM activity.” A %CK-MB activity >6% as a marker of ACS is not valid in our patient population. Laboratories should not use only CK-MB activity as a biochemical marker of ACS

Comparative study of Levofloxacin and its amide derivative as efficient water soluble inhibitors for mild steel corrosion in hydrochloric acid solution

The influence of 8-fluoro-3-methyl-9-(4-methyl-piperazin-1-yl)-6-oxo-2,3-dihydro-6H-1-oxa-3a-aza-phenalene-5-carboxylic acid or levofloxacin (P1) and newly synthesized 8-fluoro-3-methyl-9-(4-methyl-piperazin-1-yl)-6-oxo-2,3-dihydro-6H-1-oxa-3a-aza-phenalene-5-carboxylic acid-(5-methyl-pyridin-2-yl)-amide (P2) on corrosion inhibition of mild steel in 0.5 M hydrochloric acid solution was studied using weight loss and electrochemical techniques. Inhibition efficiency of P1 and P2 increased with concentration and decreased with temperature in the concentration range 0.14--0.35 mM in the temperature range 303--333 K. Thermodynamic parameters for dissolution and adsorption process were studied. Increase in energy of activation after the addition of inhibitors indicated formation of barrier film which prevents charge and mass transfer. Free energy of adsorption showed that the type of adsorption was neither physical nor chemical but comprehensive. The adsorption of the P1 and P2 on the mild steel surface was found to obey the Langmuir isotherm. Impedance measurement showed that there is increase in the polarization resistance and decrease in double layer capacitance after the addition of inhibitors. From polarization study as the shift in corrosion potential is more than 85 mV, both P1 and P2 are anodic type of inhibitors. Scanning electron microscope images confirm the formation of inhibitory film on mild steel surface. Quantum chemical calculation results well correlated with experimental results. Lower values of energy gap, ionization potential and hardness, higher value of softness make P2 better inhibitor compared to P1