Possible role of membrane proteins in mercury resistance of Enterobacter aerogenes

Mercury resistance shown by a strain of Enterobacter aerogenes was found to be determined by a plasmid. The resistance appeared to be not due to enzymatic volatilization of mercury, but due to the alteration in cellular permeability to mercury. Comparison of the outer membrane proteins was made between the resistant cells and the sensitive counterparts obtained by the treatment with mitomycin C, showing that two proteins with molecular weight of 46,000 and 44,000 had disappeared from the outer membrane along with the plasmid by the curing. These results suggest that the two membrane proteins mediating the cellular permeability to mercury compound may be responsible for the mercury resistance of the strain.

[Clinical usefulness of RI angiography using amplitude image and phase image by Fourier analysis for the detection of anteroseptal myocardial infarction (author's transl)]

In 19 patients with anteroseptal myocardial infarction, the wall motion of interventricular septum was analyzed by RI angiography using the amplitude image and the phase image. Both images were obtained from ECG gated blood pool data by Fourier analysis. Namely, from the first harmonic in the Fourier series, the heart motion was detected as the amplitude and phase of time-activity curve in each pixel. The distribution of the amplitudes and phases were displayed in color scale, and then both the amplitude and phase images were acquired. Those images allowed us visualization of the ischemic area, even if the scar was parallel to the detector. Moreover, we were able to assess the wall motion of the entire interventricular septum and to distinguish hypokinetic region and dyskinetic region from the hypokinetic region with shift of phase estimated by conventional method. Abnormal region detected by those images closely corresponded with the region of decreased radioisotope concentration in thallium-201 myocardial scintigram.

[Evaluation of myocardial infarction by ECG gated cardiac computed tomography (author's transl)]

ECG gated cardiac computed tomography (cardiac (T) was performed in 9 cases with old myocardial infarction. Seven of these had anterio-septal infarction, one had inferior wall infarction and the remaining one had posterior wall infarction. All were investigated by left ventriculography and coronary arteriography. Cardiac CT was performed after intravenous administration of contrast medium usually given as a bolus injection. The infarcted myocardium was thin and showed abnormal wall motion in cardiac CT, but the motion did not always coincide with left ventricular cineangiographic findings. In 3 cases, mural thrombi at the left ventricular apex were observed by cardiac CT, and in 2 of which the thrombi were confirmed by left ventriculography. In 2 cases, cardiac CT showed stasis of contrast medium and aneurysmal formation in the left ventricular cavity and the aneurysms were confirmed by left ventriculography. Sequential 8 mm thick non-ECG gated cardiac CT scans from the cardiac apex to the base were performed in 7 cases with anterio-septal infarction, and the infarcted area were observed in the anterior interventricular septum in 6 cases. We concluded that cardiac CT was a useful noninvasive method to detect abnormal wall motion, abnormally thin wall, mural thrombus and left ventricular aneurysm in old myocardial infarction.

[Assessment of hypertrophic cardiomyopathy by ECG gated cardiac computed tomography (author's transl)]

The applicability of ECG gated cardiac computed tomography (CT) in 12 patients with hypertrophic cardiomyopathy was examined. Six of the 12 patients had hypertrophic obstructive cardiomyopathy, including one patient with mid-ventricular obstruction. Three of the 12 patients had hypertrophic non-obstructive cardiomyopathy, and three had apical hypertrophic cardiomyopathy. The diagnosis of hypertrophic cardiomyopathy was confirmed by the angiocardiogram in all patients. Cardiac CT was performed after intravenous administration of contrast media usually given as a bolus injection. The gantry was set with positive 20 degree tilt angle. In all patients with hypertrophic obstructive cardiomyopathy except for mid-ventricular obstruction, the hypertrophied interventricular septum in the basal and mid portions was observed, and the left ventricular cavity was narrowed in systole. In a patient with mid-ventricular obstruction, the marked hypertrophied interventricular septum and antero-lateral papillary muscle were observed. In diastole, the left ventricular cavity was narrow and divided into two parts. The apical cavity was completely disappeared in systole. In all patients with hypertrophic non-obstructive cardiomyopathy, the diffuse hypertrophied interventricular septum was observed in diastole. In systole, the apical portion of the left ventricular cavity was markedly narrow and anterio-lateral papillary muscle was hypertrophic. In all patients with apical hypertrophic cardiomyopathy, the marked apical hypertrophy of the left ventricular wall was observed in diastole. It is concluded that ECG gated cardiac CT could estimate myocardial wall motion and thickness and differentiate the types of hypertrophic cardiomyopathy each other.

Protein-linked iodotyrosines in serum after topical application of povidone-iodine (Betadine)

Markedly elevated serum PBI levels occur after therapy with povidone-iodine (Betadine), an iodine-polyvinylpyrrolidone iodophor. In this study, we investigated the serum iodine compounds from a severely burned patient with normal initial thyroid function tests who was swabbed with Betadine ointment and received daily therapeutic baths in Betadine. Three and 9 days after therapy, his serum contained 93 and 168 micrograms PGI/dl, respectively (normal range, 4-8), while the serum T4 and free T4 index were normal; the serum T3 level, however, was abnormally depressed. Most of the PBI was in albumin, and hydrolysis of the serum proteins with proteases released 35% of the PBI as monoiodotyrosine, 3.2% as diiodotyrosine, 0.01% as T3, and 2.5% as T4, as determined by competitive radioassays, anion exchange, and reversed phase high pressure liquid chromatography. The same concentrations of T4 and T3 were detected before and after hydrolysis. Failure of the proteases to completely hydrolyze iodoalbumin partially explains why all of the PBI was not recovered as iodotyrosines in the serum protein hydrolysates. Povidone-iodine rapidly iodinated tyrosine residues in human serum albumin at pH 7.4 and 37 C in vitro, and the ratio of diiodotyrosine to monoiodotyrosine increased as the molar ratio of povidone-iodine to albumin was increased. It is concluded that the abnormal increase in serum PBI resulted from absorption of the iodophor into the blood where it primarily iodinated albumin and, to a lesser extent, the globulins.

Myeloma immunoglobulin interferes with serum thyroxine analysis by homogeneous enzyme immunoassay

Myeloma immunoglobulin paraproteins interfere with a homogeneous enzyme immunoassay (EMIT) for serum thyroxine. The EMIT assay failed to detect any hormone in three hyperproteinemic sera from multiple myeloma patients, although thyroxine in these sera was accurately measured by our competitive protein-binding radio-assay on small, re-usable Sephadex columns. The interference was due to turbidity of the paraproteins in the EMIT reaction mixture, resulting in an increased absorbance and a marked underestimation of hormone concentration. Thyroxine was detected (82 to 107% recovery) by the EMIT assay in ethanol extracts of myeloma sera. With 82 other sera there was an excellent correlation (r = 0.985, slope = 0.912, Y intercept (EMIT) = 6.8) of the EMIT assay with our competitive radioassay. Thus, although the EMIT thyroxine assay possesses many desirable features and it is an attractive alternative method to competitive radioassays, its susceptibility to interferences by immunoglobulin paraproteins is a troublesome liability.

Inhibitory effect of certain drugs on thyroid hormone binding by human liver cytosol

Effects of dinitrophenol (DNP), salicylate, diphenylhydantoin (DPH) and heparin on thyroid-hormone binding by human liver cytosol were studied using Pevikon thin-layer electrophoresis. Thyroxine (T4) binding by the major cytosol T4-binding protein, hT4-2, was significantly depressed with these drugs, and the displaced T4 was bound by another cytosol binding protein, hT4-1. Triiodothyronine (T3) binding by the major cytosol T3-binding protein, hT3-2, was significantly decreased with DPH and heparin, but not with DNP and salicylate. Comparative studies using human serum indicated that T4 binding by serum T4-binding prealbumin (TBPA) was inhibited with DNP and salicylate, and that binding of T4 and T3 by serum T4-binding globulin (TBG) was decreased only with DPH. The results obtained indicate that these drugs inhibit thyroid-hormone binding by the liver cytosol binding proteins for T4 and T3, and that the displaced hormones may be responsible for changes in free hormone levels in serum, and within the cells, and for the accelerated turnover of hormones.

Rapid analysis for iodotyrosines and iodothyronines in thyroglobulin by reversed-phase liquid chromatography

We describe a 10-min reversed-phase "high-pressure' liquid-chromatographic procedure for measuring tyrosine, monoiodotyrosine, diiodotyrosine, 3,5-diiodothyronine, 3,5,3'-triiodothyronine, 3,3',5'-triiodothyronine, and thyroxine. Resolution and quantitation of a mixture of these amino acids were excellent on LiChrosorb (Altex) RP-8 with isocratic elution (1.5 mL/min) with acetonitrile/water/glacial acetic acid (50/49/1 by vol). As little as 100 ng of each iodoamino acid could be detected and quantitated with a conventional 1-cm, flow-through spectrophotometric (254-nm) detector coupled to a 10-mV strip-chart recorder. Analyses for monoiodotyrosine, diiodotyrosine, 3,5,3'-triiodothyronine, and thyroxine in hog and beef thyroglobulin hydrolysates (sequential digestion with pronase and aminopeptidase) agreed well with results by anion-exchange chromatography and by competitive radioassays. To prevent interference by tryptophan in the analysis for diiodotyrosine, we batch-separated the iodoamino acids by anion-exchange chromatography before the procedure. The procedure we describe seems generally useful for detection and quantitation of thyroid hormones, thyroid hormone metabolites, and iodotyrosines.

Rapid analysis for iodotyrosines and iodothyronines in thyroglobulin by reversed-phase liquid chromatography

We describe a 10-min reversed-phase "high-pressure' liquid-chromatographic procedure for measuring tyrosine, monoiodotyrosine, diiodotyrosine, 3,5-diiodothyronine, 3,5,3'-triiodothyronine, 3,3',5'-triiodothyronine, and thyroxine. Resolution and quantitation of a mixture of these amino acids were excellent on LiChrosorb (Altex) RP-8 with isocratic elution (1.5 mL/min) with acetonitrile/water/glacial acetic acid (50/49/1 by vol). As little as 100 ng of each iodoamino acid could be detected and quantitated with a conventional 1-cm, flow-through spectrophotometric (254-nm) detector coupled to a 10-mV strip-chart recorder. Analyses for monoiodotyrosine, diiodotyrosine, 3,5,3'-triiodothyronine, and thyroxine in hog and beef thyroglobulin hydrolysates (sequential digestion with pronase and aminopeptidase) agreed well with results by anion-exchange chromatography and by competitive radioassays. To prevent interference by tryptophan in the analysis for diiodotyrosine, we batch-separated the iodoamino acids by anion-exchange chromatography before the procedure. The procedure we describe seems generally useful for detection and quantitation of thyroid hormones, thyroid hormone metabolites, and iodotyrosines.

Presystolic pulmonary valve opening in constrictive pericarditis

Right heart pressure tracings were studied in 5 cases with constrictive pericarditis. The pressure of the A-wave in the right atrium of these cases was higher than the pulmonary arterial diastolic pressure. In addition, a presystolic wave appeared in the pulmonary arterial and the right ventricular pressure tracings, in coincidence with atrial systole. The pressure of this presystolic wave was similar to that of the right atrial A-wave. This suggests that the pulmonary valve opens following atrial systole, and then the blood flows into the pulmonary artery in the presystolic phase in patients with constrictive pericarditis. In 2 cases, pulmonary valve echograms were recorded. The a-dip in these 2 cases was as deep as 8.4 mm and 9.6 mm (1.8-4.1 mm with a mean of 2.80 mm for normal men), and its duration was prolonged to 0.17 sec and 0.18 sec (0.10-0.13 sec with a mean of 0.115 sec for normal men). In conclusion, such a deep and prolonged a-dip on pulmonary valve echogram is presumably a sign of presystolic pulmonary valve opening.

Thyroid hormone contamination in crystalline diiodotyrosine

Crystalline preparations of diiodotyrosine contain trace quantities of thyroxine that can be detected by several competitive radioassays and by chromatography on Sephadex. Spontaneous coupling of diiodotyrosine to thyroxine during iodination of tyrosine and coprecipitation of hormone with diiodotyrosine crystals are likely explanations for the trace contamination. We discuss the significance of these findings in relation to studies on the biosynthesis of thyroxine.

Thyroid hormone contamination in crystalline diiodotyrosine

Crystalline preparations of diiodotyrosine contain trace quantities of thyroxine that can be detected by several competitive radioassays and by chromatography on Sephadex. Spontaneous coupling of diiodotyrosine to thyroxine during iodination of tyrosine and coprecipitation of hormone with diiodotyrosine crystals are likely explanations for the trace contamination. We discuss the significance of these findings in relation to studies on the biosynthesis of thyroxine.