Lysosomal enzyme activities in normals and in patients with chronic liver diseases

The maximal activities of liver lysosomal enzymes (acid phosphatase and cathepsin D) were found to be increased in patients with chronic active hepatitis, cirrhosis and primary hepatocellular carcinoma. The ratio between maximal and basal activity (an expression of the degree of retention of the enzymes to lysosome) of acid phosphatase was significantly decreased in patients with chronic active hepatitis and cirrhosis whereas that of cathepsin D did not show any significant changes between normal and various liver disorders. Serum levels of both the enzymes were elevated significantly in patients with cirrhosis and primary hepatocellular carcinoma.     

The sorbitol-oxidizing enzyme of red blood cells.

The sorbitol-oxidizing enzyme of human erythrocytes has been partially purified and characterized. Its kinetic characteristics were found to be similar to the sorbitol dehydrogenase of sheep liver and the DPN-xyluloxe dehydrogenase which have been isolated from sheep liver and guinea pig liver, respectively. Although this enzyme is able to oxidize sorbitol relatively efficiently, it has very little activity toward dulcitol, and therefore cannot account for the high K-m pathway of methemoglobin reduction by galactose.     

Lysosomal enzymes in medium from cultured skin fibroblasts from normal individuals and patients with lysosomal diseases.

The release of acid hydrolases from cultured skin fibroblasts into the cell culture medium was studied in several lysosomal storage disorders (GM1-gangliosidosis, Fabry's disease, Hurler's disease, mannosidosis, and mucolipidosis). The levels of different activities were proportional to time (up to 44 h after medium change) and cell density with the exception of beta-glucosidase, which was not released. Culture medium from the fibroblasts of mucolipidosis patients exhibited higher activity of acid hydrolases than medium from cells of patients with GM1-gangliosidosis, Fabry's disease, Hurler's disease, and mannosidosis. These cells, however, exhibited somewhat higher levels of enzyme activity in their culture medium than control fibroblasts. The total production of acid hydrolases was yet rather similar in fibroblasts from controls and patients. Differential centrifugation showed that the highest specific activity of acid hydrolases was seen, as expected, in the lysosomal fraction, except in fibroblasts from patients with mucolipidosis, where the supernatant exhibited most activity. beta-Glucosidase, however, showed a normal differential centrifugation pattern also in fibroblasts from these patients.     

Lysosomal enzymes in normal and Chediak-Higashi blood leukocytes.

A method of blood granylocyte concentration and isolation of granules from both normal and neutropenic Chediak-Higashi syndrome (CHS) patients is described. the intracellular distribution of activity for several hydrolases in CHS granulocytes differs from normal; significantly more activity is present in the cytoplasmic fraction and correspondingly less is granule-associated. Isolated CHS granules are not more sensitive to the labilizing agents vitamin A, progesterone, or etiocholanolone. Specific activities of myeloperoxidase and ss-glucuronidase in CHS granulocytes are lower than normal while alkaline phosphatase is elevated. Other lysosomal enzyme activities are normal. Lysosomal enzyme distribution and content are similar in CHS and normal mononuclear cells. The possible significance of these findings is discussed.     

Suppressor function of peripheral blood mononuclear cells in normal individuals and in patients with systemic lupus erythematosus.

Normal peripheral blood mononuclear cells demonstrated increased DNA synthesis and secretion of newly synthesized protein when suboptimal concentrations of Concanavalin A (Con A) were added to the cultures after 24-h incubation in vitro. Cells stimulated by Con A, 1 mug/ml, after 24-h incubation demonstrated 3.0 times more tritiated thymidine incorporation, and 4.4 times more 14C-amino acid incorporation into newly synthesized secreted protein, than cells stimulated at 0 h (P less than 0.001). The acquisition of increased responsiveness was not abrogated by washing and resuspending the cells in fresh medium. Since the increased responsiveness could be inhibited by the addition to the cultures of small numbers of cells previously activated by Con A it is suggested that the enhanced reactivity acquired in culture represents the loss of a subpopulation of suppressor cells that modulate the T-lymphocyte response. Cells from nine patients with active, untreated systemic lupus erythematosus demonstrated normal responses to optimal concentrations of Con A added at 0 h, but an impaired response to Con A, 1 mug/ml. When these cells were incubated for 24 h, a significant increased response to Con A was not observed. This observation suggests that patients with active SLE lack circulating suppressor cells. When seven SLE patients were again studied after corticosteroid therapy had led to clinical improvement, the response to Con A, 1 mug/ml, added after 24-h incubation was similar to that observed in normal controls, suggesting that suppressor function in SLE returns as disease activity declines.     

Lysosomal acid phosphatase: activity and isoenzymes in separated normal human blood cells

The present study was devised to investigate the activity and isoenzymes of lysosomal acid phosphatase in individual normal human blood cells, including the T- and B-population of lymphocytes, with the aim to contribute to the classification of haematopoietic neoplasias on the basis of cell specific isoenzyme patterns. Platelets, erythrocytes, granulocytes, monocytes and T-lymphocytes were isolated from blood by gradient centrifugation or immune adsorption. B-lymphocytes were obtained from human tonsils. After purity control and isolation of lysosomes the concentration of acid phosphatase was assayed using the conventional spectrophotometric method. Isoenzymes were separated by isoelectric focusing on polyacrylamide thin layer slabs. Monocytes revealed the highest activity with 14 mU/10(7) cells, about three times more than granulocytes. T-lymphocytes showed an activity of 2.85 mU/10(7) cells and B-lymphocytes of 1.83 mU/10(7) CELLS. The lowest activity was found in platelets with 0.08 mU/10(7) cells. Granulocytes showed 12 isoenzyme bands, whilst the number for monocyte, B-lymphocytes, T-lymphocytes and platelets were respectively 11, 12, 1 and 4 isoenzyme bands. Thus it became evident that the different blood cell populations can be distinguished on the basis of their acid phosphatase isoenzyme pattern.     

High in-hospital mortality of intensive care patients with nucleated red blood cells in blood.

The detection of nucleated red blood cells (NRBCs) in blood of patients suffering from a variety of severe diseases is known to be highly associated with increased mortality. Blood analyzers to routinely measure NRBC concentrations are now available. However, the diagnostic and prognostic significance of this parameter for intensive care patients has not been evaluated. Using a Sysmex XE-2100 analyzer, NRBC concentrations were determined in blood samples from 421 patients treated in intensive care units (general and accident surgery, cardiothoracic surgery, and internal medicine) of a university hospital. NRBCs were found at least once in 19.2% of all patients. The mortality of NRBC-positive patients (n=81) was 42.0% (n=34); this was significantly higher (p<0.001) than the mortality of NRBC-negative patients (5.9%, n=340). The NRBC concentration was 115+/-4x10(6)/l (median 40x10(6)/l; range 20-2930x10(6)/l) at initial detection of NRBCs in the blood. Mortality increased with increasing NRBC concentration and increasing frequency of occurrence. With regard to in-hospital mortality, NRBCs in blood showed sensitivity and specificity of 63.0% and 87.2%, respectively. The detection of NRBCs is highly predictive of death, the odds ratio after adjustment for other laboratory prognostic indicators being 1.01 (p<0.01) for each increase in the NRBC concentration of +1x10(6)/l. NRBCs were detected for the first time, on average, 13 days (median 8 days) before death. The routine analysis of NRBCs in blood is of high prognostic power with regard to in-hospital mortality of critically ill patients. Therefore, this parameter may serve as an early indicator for patients at increased mortality risk.     

Isolation of fetal nucleated red blood cells from maternal blood in normal and aneuploid pregnancies.

Fetal nucleated red blood cells (NRBC) have been widely reported in maternal blood during pregnancy. However, there is no consensus with regard to their presence in all pregnancies. Therefore, the usefulness of developing a fetal NRBC-based noninvasive method suitable for clinical prenatal diagnosis remains uncertain. Fluorescence in situ hybridization (FISH) method was used to evaluate the ability of one of our own monoclonal antibodies (mAb), 2B7.4, to isolate fetal NRBC from maternal blood by magnetic activated cell sorting (MACS). Our mAb was able to isolate from 25 to 822 NRBC from all of the 45 maternal blood samples included in this study. A correct diagnosis was achieved in 21 out of 24 pregnancies carrying trisomic fetuses (87.5%), with a fetal/maternal NRBC frequency of 8.4%. In contrast, a significantly lower percentage of fetal NRBC (0.2%) was observed in 22% of pregnancies carrying a chromosomally normal male fetus, that were correctly predicted. In conclusion, using 2B7.4 mAb we succeeded in isolating NRBC from the maternal blood samples, but most of the isolated cells were maternal in origin. Nevertheless, a higher number of fetal NRBC was found in the peripheral blood of pregnant women carrying aneuploid fetuses, which could allow development of a screening method for prenatal diagnosis of fetal aneuploidies.     

Characterization of protoporphyrin in red blood cells of patients with erythropoietic protoporphyria.

It was investigated whether the protoporphyrin that can be extracted from red blood cells of erythropoietic protoporphyria (E.P.P.) patients is present in the cells as free molecules or protein-bound. With isoelectric focusing and with starch gel electrophoresis it could be shown that virtually all protoporphyrin in the erythrocytes is protein-bound. It is very likely that the protoporphyrin is bound to hemoglobin at heme-binding sites. This was indicated by several observations: 1. With isoelectric focusing the protoporphyrin-protein complex is focused at a pH only slightly higher than the isoelectric point of hemoglobin. 2. With chromatography on Sephadex columns it appeared that hemoglobin and the protopotphyrin-protein complex have the same molecular weight. 3. A Heme-protoporphyrin exchange occurred when the heme-globin bond was labialized by conversion to hemiglobin. The resulting protoporphyrin-hemoglobin complex had the same electrophoretic mobility with starch gel electrophoresis as the protoporphyrin-protein complex, extracted from red blood cells of E.P.P. patients.     

Properties of a membrane-bound phosphatase activity in normal and abnormal red blood cells.

A neutral, membrane-bound, phosphatase activity was characterized in normal red blood cells, using p-nitrophenylphosphate as substrate. Its specific activity was 1.59 nmol mg-1 min-1. The kinetics were of the Michaelis type: KM,app = 2.5 X 10(-3) M. It was stimulated by K+ and inhibited by ouabain, a behaviour reminiscent of (Na+ + K+)-ATPase. In 10 patients with homozygous sickle cell disease and in 11 patients with unidentified congenital hemolytic anemias, the specific activity was significantly increased. In general, the phosphatase retained Michaelis-Menten kinetics. However, in four patients from the same family with an unidentified hemolytic anemia, the kinetics yielded a biphasic curve instead of a rectangular hyperbola, a change consistent with the existence of an inhibition by substrate excess. From detailed analysis of the curve, the apparent inhibitor constant for pNPP was determined: Ki,app approx. 2.5 X 10(-2) M. This novel abnormality of the red cell membrane might be the distinctive feature of a given type of congenital hemolytic anemia.     

Effect of parathyroid hormone on the fragility and enzyme activities of red blood cells from young and mature rabbits

The effect of parathyroid hormone on erythrocytes from newborn and adult rabbits was studied in relation to the fragility pattern in hypotonic salt solutions and the activities of Ca- and Mg-dependent ATPases. Median osmotic fragility of red blood cells from newborn rabbits was significantly higher than in red blood cells from mature rabbits. Parathyroid hormone increased the mean osmotic fragility of red blood cells from newborn and adult rabbits, but showed the greater effect on those from newborns. Similarly, the hormone stimulated to a much greater extent the Ca-ATPase, but not the Mg-ATPase in red blood cells from the newborn rabbits, in comparison with red blood cells from adult rabbits. Parathyroid hormone, which is greatly elevated in the blood of patients with chronic renal failure, may be one cause for the anaemia seen in these patients, and its effect, which is mediated by Ca-ATPase activity, is stronger on young red blood cells. Significant morphological changes in the young red blood cells, observed by scanning electron microscopy, were caused by parathyroid hormone.     

Lysosomal enzyme activities in fresh and frozen chorionic villi and in cultured trophoblasts

Fifteen lysosomal enzyme activities were compared in 14 presumed normal chorionic villus specimens that were each divided, processed and analyzed as fresh tissue, tissue frozen for 1 week, and cultures established from minced whole villi. Most of the activities determined in the chorionic villus tissue were not affected significantly by freezing. However, activities for most enzymes were significantly different from those determined in the cultured cells. Our experience with first trimester prenatal evaluations for several lysosomal disorders showed that the limited amount of tissue obtained is not always sufficient for thorough analysis and thus, cultured trophoblasts derived from the tissue specimen should also be examined. The results of this study stress the importance of using appropriate tissue-type and cell-type controls to establish the normal range in the respective analyses.     

A strong antibody reacting with enzyme modified E positive red blood cells

A high titer antibody was discovered in a healthy young man of blood group A1 R2r. The antibody strongly agglutinated all E positive red blood cells including his own, which had been modified by papain, ficin and bromelin, but only very weakly when modified by trypsin. The antibody was shown to be an IgM antibody. It did not react with unmodified red blood cells.     

Lysosomal enzyme pattern in lung lymph and blood during E. coli sepsis in sheep

Systemic release of lysosomal enzymes and local release in the pulmonary microcirculation from sequestrated and activated leucocytes could be an important factor in the development of the lung microvascular injury seen after septicaemia. The maximal activities of 11 lysosomal acid hydrolases (acid phosphatase, alpha- and beta-glucosidase, alpha- and beta-galactosidase, alpha-mannosidase, beta-acetylglucosaminidase, beta-glucuronidase, arylamidase and cathepsins B and C) were measured in serum and lung lymph from seven sheep before and after infusion of live E. coli bacteria. In the early phase of septicaemia (the first hour) the activities of eight enzymes were increased in serum and/or lung lymph (1.1 to 2X pre-infusion values). In the late phase, 3-4 h after sepsis, there were significantly elevated serum activities of beta-glucosidase (5.4X), alpha- and beta-galactosidases (2.7X, 1.5X), beta-acetylglucosaminidase (2.0X) arylamidase (1.2X) and cathespin B (1.7X). In lymph acid phosphatase (1.7X), alpha- and beta-glucosidases (1.6X, 6.4X), alpha- and beta-galactosidases (2.1X, 1.7X). Beta-acetylglucosaminidase (2.6X), and beta-glucuronidase (4.0X pre-infusion) were elevated. The findings of a heterogenicity of changes in serum and lymph activities, as well as the large molecular sizes of some of the enzymes with changed activities indicated to us that permeability changes were not major causes of increased lymph enzyme activities. The results could indicate a local release of enzymes either from sequestrated leucocytes or lung tissue due to local reactions in the lung or lung microvessels. The heterogenous changes in activities for the various lysosomal enzymes as found in the present study indicated that measurement of only one enzyme could be misleading.(ABSTRACT TRUNCATED AT 250 WORDS)