Response of plasma lipoproteins and acute phase proteins to myocardial infarction.

Plasma concentrations of lipoprotein-lipids, apolipoprotein B (apoB) and of seven other proteins have been estimated serially in 27 patients up to three months following myocardial infarction. Results were compared with those from age- and sex-matched control subjects. At three months the mean total, low density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol concentrations were higher than those of the control subjects, whereas very low density lipoprotein (VLDL) cholesterol, total and VLDL triglyceride, and total and LDL apolipoprotein B concentrations were not significantly different. Relative to concentrations at three months total and LDL cholesterol and apolipoprotein B concentrations fell markedly, and a slight fall occurred in HDL cholesterol following infarction. VLDL cholesterol and total and VLDL triglyceride were decreased only on day one. Albumin and transferrin concentrations were higher and alpha 1-acid glycoprotein was lower at three months than in the control subjects; alpha 2-macroglobulin, caeruloplasmin, haptoglobin and immunoglobulin IgM were not significantly different. Following infarction albumin and transferrin fell, alpha 2-macroglobulin did not change, and alpha 1-acid glycoprotein, caeruloplasmin, haptoglobin and IgM rose. The changes in both lipids and protein are probably part of the general metabolic response to trauma.     

Studies of blood ascorbic acid levels in acute myocardial infarction.

Fasting serum samples from 53 patients with an acute myocardial infarction were investigated for their vitamin C content during the first week of their illness. The vitamin C levels found were generally within the accepted normal limits. However, there were highly significant lower levels on the second to the fifth post-infarction days, as compared with those found on days six to eight.     

Plasma malonaldehyde levels during myocardial infarction

Malonaldehyde levels were determined in plasma from patients with myocardial infarction. Patients had significantly elevated mean values when compared with normal subjects. Furthermore, in patients an increase in malonaldehyde was observed during the post infarction period. It seems that the plasma malonaldehyde in patients with myocardial infarction could reflect the platelet aggregability.     

Creatine phosphokinase isoenzymes: A comparison of a kinetic and an electrophoretic method in the diagnosis of myocardial infarction

A comparison has been made of the results of the levels of the MB isoenzyme of creatine phosphokinase by a kinetic and an electrophoretic method performed on patients suspected of having myocardial infarction. Reviewed in depth are those cases in which discrepant results have occurred. On the basis of the combined clinical and laboratory data, the kinetic method is a more sensitive but less specific indicator of myocardial necrosis. Thus, the kinetic method may be used as a screening test, with confirmation of positive results by electrophoresis.     

The urinary excretion of 3-methoxy-4-hydroxyphenylglycól in acute myocardial infarction.

Urinary excretion of 3-methoxy-4-hydroxyphenylglycol (MHPG), noradrenaline, adrenaline and vanillylmandelic acid (VMA) was studied in 30 patients with acute myocardial infarction. The excretion of MHPG was higher in patients with myocardial infarction than in the control group, with no difference between uncomplicated and complicated courses of the disease. The excretion of MHPG showed a negative although not significant correlation with noradrenaline and VMA during the first days of infarction and a statistically significant positive correlation on the 5th day of the disease. The possible causes of the changes observed are discussed.     

Critical evaluation of serum uric acid levels in acute myocardial infarction

Serial measurements of serum uric acid were performed on patients suffering from acute myocardial infarction. Nearly 80 percent of the cases demonstrated a fall in uric acid concentrations during the first two days of hospitalization and a subsequent return to initial levels within six to eight days. There was a relationship between the decrease in uric acid levels and the serum lactate dehydrogenase activity.No evidence could be found that male patients were hyperuricemic as compared to control subjects. However, female patients between 40 and 60 years of age demonstrated significantly higher uric acid levels than healthy women of corresponding ages, even after adjustment for diuretic use.     

Lipoprotein fractionation by a precipitation method. A simple quantitative procedure.

A method is described for quantitation of the three major classes of serum lipoproteins. After precipitation of very low density lipoprotein (VLDL) using sodium dodecyl sulphate, the cholesterol and triglyceride content of this lipoprotein class is directly measured. In a second aliquot serum high density lipoprotein (HDL) lipids are measured after precipitation of VLDL and low density lipoprotein (LDL). LDL cholesterol and triglyceride contents are calculated by difference. The procedure requires 2 ml serum, and sensitivity is adequate to permit lipoprotein analyses on umbilical cord serum. Close agreement is observed between this precipitation method and preparative ultracentrifugation.     

A comparative study of three approaches to the routine quantitative determination of spinal fluid total proteins

The concentration of total protein in spinal fluid from 164 patients has been assayed by three methods based on different principles; a biuret, a dye-binding and a nephelometric procedure. Major proteins were quantified by immuno-chemical methods in order to get an estimate of the accuracy, and used for standard curves in the different methods in order to elucidate differences between total protein values. Based on the mean total protein values in relation to major protein values, total imprecision and practicability we conclude that the dye-binding technique is more accurate, precise and convenient than the other two methods for daily routine determination of total protein in spinal fluid.     

alpha1-Antichymotrypsin interaction with cationic proteins from granulocytes.

Human granulocytes contain cationic proteins with chymotrypsin-like activity. These proteases showed a higher relative affinity for alpha1-antichymotrypsin than for alpha1-antitrypsin but the highest affinity for alpha2-macroglobulin. The complexes between cationic protein and alpha1-antichymotrypsin migrate as beta-globulin on agarose gel electrophoresis.     

Electrophoretic modifications of three enzymes in extracts of human and bovine lens. Posttranslational “aging” of lens enzymes

Electrophoretic modifications have been found in extracts from human and bovine lenses for three enzymes: glucose-6-phosphate dehydrogenase, triosephosphate isomerase and nucleoside phosphorylase. Increased anodic mobility is observed in all cases. It is more pronounced than in red cell lysates, also more evident in lenses from adult than from young animals. These results give evidence of posttranslational “aging” of enzyme molecules in lenses.     

Familial hyper-alpha-lipoproteinaemia. Further studies on serum lipoproteins and some serum enzymes.

Some new data are given concerning a family whose members are characterized by high levels of alpha-(HDL)-cholesterol. Data from the new members of the family, not previously studied, confirm that the defect is not associated with any cardiac or neurological defect nor with xanthomata. Studies performed to assess the polypeptide composition of HDL of the affected members resulted in completely normal results. The post-heparin lipolytic activity (PHLA), the liver lipase and the lecithin-cholesterol acyltransferase (LCAT) activities also proved to be within the normal limits.     

Acid beta-glucosidase and the diagnosis of Gaucher's disease in liver and spleen.

Variable amounts of residual 4-methylumbelliferyl-beta-glucosidase activity gave rise to difficulties in the diagnosis of Gaucher's disease using spleen and particularly liver. Soluble and particulate components of beta-glucosidase, which interfere with the diagnosis, may be eliminated by preincubation of homogenates at pH 3.0 or with 100 mM sodium chloride at pH 4.0. After either of these treatments the optimum of acid beta-glucosidase was pH 4.5 and diagnosis of Gaucher's disease could be more easily made using homogenates of spleen and liver. There was residual acid beta-glucosidase activity in one of the Gaucher livers.     

A novel alkaline phosphatase, a minor component of normal liver phosphatases.

A novel alkaline phosphatase differing from the so-called liver-specific isoenzyme was found in four out of twenty-four normal adult livers. Although the mobility of this enzyme was the same as that of so-called liver-specific alkaline phosphatase on the polyacrylamide gel electrophoretogram, its mobility was not altered following neuraminidase treatment, while that of the liver-specific enzyme was affected by the same treatment. Both enzymes also differed in other enzymatic and immunologic properties. The enzyme, however, resembled the so-called intestinal alkaline phosphatase in many enzymatic and immunologic properties. Thus, the inhibition patterns by amino acids, EDTA and inorganic phosphate, the pH optima, KM values for phenyl phosphate and reactivity with anti-intestinal alkaline phosphatase antibody were quite similar for both enzymes. Differences in the properties of this enzyme and intestinal alkaline phosphatase were in sensitivity to denaturation by treatment with heat and urea and to inhibition by Levamisole. The possible origin of the enzyme in normal liver and its relationship to the Kasahara isoenzyme and fetal intestine-type in hepatoma is discussed.     

A method for enhancing the stability of thiol-containing enzymes immobilised on nylon.

The limited stability of immobilised enzymes is a major factor restricting their use in clinical chemistry. The immobilisation procedure described here affords a simple method of enhancing the stability of certain enzymes immobilised on nylon. Studies with alcohol dehydrogenase and glyceraldehyde-3-phosphate dehydrogenase have indicated that a significant increase in stability can be obtained using this immobilisation procedure as compared with conventional procedures. As anticipated the immobilisation procedure was unsatisfactory for oxidases such as glucose oxidase.     

An investigation into creatine kinase and other plasma enzymes in thyroid disorders.

The relationship between plasma protein bound iodine (PBI) level and creatine kinase (CK) activity was investigated in 143 males and 528 females suspected of various thyroid disorders; there was significant negative correlation between low PBI level and raised CK activity. CK, aldolase, lactate dehydrogenase (LD), aspartate transaminase (AST), and alanine transaminase (ALT) activities were determined in plasma from patients with reduced PBI levels; apart from CK, LD was the only enzyme increased in an appreciable number of cases. A further series of specimens was collected from 66 patients with low PBI levels and the CK isoenzymes investigated. In all of these MM was the main form present; a trace of MB was found in 6. These findings do not explain the elevation of CK in hypothyroidism which may be a non-specific effect.     

Comparison of human membrane-bound neutral arylamidases from small intestine, lung, kidney, liver and placenta.

Human membrane-bound neutral arylamidases were solubilized from small intestinal mucosa, lung, kidney, liver and placenta with trypsin. These five membrane-bound neutral arylamidases were identified by polyacrylamide gel-disc electrophoresis. The heat sensitivity of each enzyme was in the order, liver and placenta greater than kidney greater than lung greater than small intestine. This order correlates with that of electrophoretic mobility, except for the placental membrane-bound neutral arylamidase. Five membrane-bound neutral arylamidases have the same molecular weight, 240 000, as estimated by Sephadex G-200 gel filtration. The five membrane-bound neutral arylamidase have very similar KM values (8.7 x 10(-5) M towards L-alanyl-beta-naphthylamide), optimal pH values, hydrolysis ratios towards L-alanyl-beta-naphthylamide and L-leucyl-beta-naphthylamide, and sensitivities of inhibition by chelators or amino acids. These results suggest that the multiple forms of membrane-bound neutral arylamidase found in five different human organs are organ-specific isoenzymes.     

Short chain fatty acids in plasma and brain: quantitative determination by gas chromatography.

A reliable and practicable method for the determination of short chain fatty acids in plasma and brain tissue is presented. The sample preparation by partition chromatography on silicic acid allows subsequently a quantitation of short chain fatty acids without interference by methylmalonic acid, or other more polar compounds. With the gas-chromatographic system 2-methylbutyrate is separated from isovalerate. Reference values are given for plasma. The system is also useful in combination with mass spectrometry.     

Determination of lysosomal enzymes in saliva. Confirmation of the diagnosis of metachromatic leukodystrophy and fucosidosis by enzyme analysis.

This paper deals with the measurement of acid hydrolases in uncentrifuged and centrifuged saliva of normal controls and the determination of some of their physical characteristics such as pH optimum, thermal stability, and residual activity after freezing and storage. From this study it appears that beta-D-glucosidase sediments totally, whereas the other enzymes show varying residual activity in the supernatant after centrifugation. In the saliva from 2 patients with metachromatic leukodystrophy and 2 patients with fucosidosis a deficiency of arylsulphatase A and alpha-L-fucosidase, respectively, was found.