The detection of myoglobin in urine and its distinction from normal and variant haemoglobins

Victims of severe injuries frequently pass haemoglobin, myoglobin, or both proteins in their urine. If the kidneys of such persons are to be considered as donor material for transplantation, a pathology department may be requested to identify which of these pigments is present. If freshly passed urine is available, haemoglobinuria in the absence of myoglobinuria may be rapidly identified by spectroscopy. However, the rapid degradation of myoglobin to the met-myoglobin form will make spectroscopic recognition of this pigment in the urine unreliable. In the absence of variant haemoglobins, myoglobin may be easily distinguished from normal haemoglobin by routine electrophoresis on paper, starch gel, or cellulose acetate at alkaline pH. The electrophoretic method of choice in the presence of variant haemoglobins utilizes polyacrylamide gel at 12 g/100 ml as a supporting medium. At this concentration, the migration both of haemoglobin and its variants is sufficiently retarded to allow the easy recognition of myoglobin.     

Method using ortho-tolidine for the quantitative determination of haemoglobin in serum and urine

Following a study of the spectrophotometric properties of ortho-tolidine and its oxidation products, with particular attention to variation brought about by change in the hydrogen ion concentration, a method for the quantitative estimation of haemoglobin in serum and urine in which ortho-tolidine is substituted for benzidine in a peroxidase system is described. The method is designed to measure haemoglobin value within the range 0-125 mg. per 100 ml. Evidence is presented showing that it gives results equal in accuracy and reproducibility to a benzidine method in common use and for reasons stated is a more satisfactory technique for estimating the haemoglobin content of urine.     

Improvement of ethyl glucuronide determination in human urine and serum samples by solid-phase extraction

An improved method for the determination of ethyl glucuronide (EtG) in human serum and urine was developed using solid-phase extraction (SPE) and gas chromatography (GC) with mass spectrometric detection (MS). EtG was isolated from serum and urine using aminopropyl SPE columns after deproteination with perchloric acid and hydrochloric acid, respectively. The chromatographic separation was performed on a DB 1701 fused-silica column. At a signal-to-noise ratio of 3:1, a quantification limit of 173 and 560 ng/ml and a detection limit of 37 and 168 ng/ml could be determined for serum and urine, respectively. This indicates high specificity and sensitivity of the described method. The mean absolute recovery was approximately 85%, while intra- and inter-day precision of the assay were all less than 7.5%. The linearity of the calibration curves was satisfying as indicated by correlation coefficients of >0.993. The presented method provides the basis for determination and identification of EtG in human serum and urine samples in a low-concentration range for monitoring alcohol consumption during treatment for alcohol dependence and comorbid alcohol abuse of psychotherapy patients.     

Improvement of the uric acid determination by the carbonate method for serum and urine

An improved colorimetric procedure for determining uric acid by the carbonate method in serum and urine is described, using a 20% sodium carbonate solution with urea. Reliable results are also obtained in high concentrations of uric acid.     

The detection of myoglobin in urine and its application to the diagnosis of myocardial infarction.

An indirect haemaglutination method was developed for the immunochemical detection of myoglobin in human urine. Myoglobin was found in the urine of 84% of 44 patients with acute myocardial infarction. In contrast, it was detected in the urine of 2.7% of 147 control subjects and in none of a control group of 15 patients who had received intramuscular injections. In patients with myocardial infarction, myoglobin was detected in most but not all urine specimens collected between 10 and 50 hours after the onset of chest pain. The results suggest that the detection of myoglobin in urine may be a valuable addition to present tests for the diagnosis of acute myocardial infarction.     

An enzyme-immunoassay for myoglobin in human serum and urine. Method development, normal values and application to acute myocardial infarction.

An enzyme-immunoassay has been developed for the detection of myoglobin in human serum and urine which is specific, accurate, precise, and has a sensitivity of 3 ng/ml. When compared with radioimmunoassay, the enzyme-immunoassay gives markedly similar results. Sera from normal adults had a myoglobin concentration in the range 3-65 ng/ml, and 64% of the same group had detectable myoglobinuria (range 3-11.5 ng/ml). All of 8 patients with definite acute myocardial infarction had raised serum myoglobin levels (range 200-1125 ng/ml) either at admission or 4 h later. Myoglobin concentration returned to normal in 6 patients, and in the remaining 2 patients there was evidence of infarct extension. Urinary myoglobin excretion was variable. One patient with possible acute myocardial infarction had elevated serum myoglobin (413 ng/ml 4 h post admission) and 5 patients with no evidence of infarction had normal levels (15-53 ng/ml). The results suggest that detection of serum myoglobin by enzyme-immunoassay may be a valuable test in the early diagnosis of acute myocardial infarction.     

Antibacterial activity of nifuratel in urine and serum

The minimum inhibitory concentrations of nifuratel for 205 randomly selected isolates from urinary tract infections were tested by tube dilution. Of these, 177 (86.3%) were resistant to more than 6 mug/ml and 140 of 141 (99.3%) strains of Escherichia coli were resistant to more than 3 mug/ml. Urine levels of nifuratel were examined in two groups: one group had 400 mg given once and the other group had 2 g given over 24 hours. In both groups samples of urine were collected every hour for seven hours after the last dose. After one 400-mg dose the maximum urine level achieved by any subject was 2.0 mug/ml and the mean maximum level was 0.75 mug/ml. With the 2 g total dose, the maximum level noted was 4 mug/ml and the mean maximum level was 1.8 mug/ml. No measurable inhibition was noted in any of the blood samples removed at one and a half to two hours after the last dose.     

Nitrazepam (Mogadon) in blood serum and urine and librium in urine

A method is described for the determination of nitrazepam and its reduced product in blood serum and urine. The metabolite, the reduced product, is the principal substance to be encountered in these fluids. A method is also described for the determination of librium (and the lactam) in urine.