Hydrolytic enzyme activities, mainly from lysosomal localization, in sera from patients who ingested a toxic oil

Levels of serum cathepsin L and several glycosidases in patients operated for colorectal cancer

The activities of several glycosidases and cathepsin L were determined in the blood serum of a control group of ten healthy humans in comparison with a group (group I: 32 subjects) of preoperative colorectal cancer patients (1 week before surgical exeresis) and with another two groups: group II, comprising 18 operated subjects (1 week after surgery), and group III, of 15 operated subjects (4 months after surgery). All subjects were 48-88 years old. Both 'enzyme activity' and 'specific activity' determinations of serum beta-galactosidase, alpha-L-fucosidase and cathepsin L revealed peculiar profiles that differed from one another. Control values differed from those of some stages of the pathological groups, but not of others. These values were compared also with the levels of total, lipid- and glycoprotein-associated serum sialic acid. The usefulness of some assays (especially cathepsin L activity measurement) in the follow-up of the health status of humans operated for colorectal cancer is discussed.

Evaluation of the activities of eight lysosomal hydrolases in sera of humans, rats and pigs of different ages

The activities of 21 enzymes (belonging to four classes of enzymes) involved in different metabolic pathways were assayed in blood sera of healthy young and adult/elderly groups of humans, rats and pigs, to determine whether activity changes coinciding with changes in age and aging could be detected. In all three species analysed, measurable activities (performed by highly specific and sensitive techniques, generally spectrofluorimetric procedures) were found, usually following a decreasing order of: among glycosidases, beta-N-acetylglucosaminidase (NAG) > alpha-L-fucosidase > alpha-mannosidase > beta-glucuronidase > beta-galactosidase > alpha-galactosidase. In addition, among esterases very high values were found for arylesterase and acid phosphatase. By contrast, no measurable activity was found for the remaining enzymes assayed (8 hydrolases, 1 oxidoreductase, 3 transferases and 1 lyase). In the elderly group of humans, significantly higher activities (P < or = 0.05) were found for NAG, alpha-mannosidase and beta-glucuronidase in comparison to the adult and young groups. However, several activities in rats and all activities in pigs decreased with age. In conclusion, differences in the activities of 6 lysosomal glycosidases and 2 esterases (but no significant differences for another 13 enzymes belonging to several enzyme classes) are found in the sera of healthy humans, rats and pigs. These differences coincide with changes observed in aging.

Variation in serum arylesterase, beta-glucuronidase, cathepsin L and plasminogen activators during pregnancy

To determine whether the activities of certain hydrolases (arylesterase, beta-glucuronidase, cathepsin L, plasminogen activators, arginase, glutaminase, asparaginase and adenosine deaminase) are changed during pregnancy, three groups of 15 apparently healthy women (aged 18-38 years) in their first, second and third trimester of pregnancy were compared to a control group formed of 15 non-pregnant women of similar ages. Enzyme and specific activities gradually increased from the first to the end of the third trimester of pregnancy for arylesterase and beta-glucuronidase, these increases being statistically significant (P < 0.01) in comparison to controls. However, as regards cathepsin L and plasminogen activators, the greatest increase was found in the second trimester. Arginase, glutaminase and asparaginase activities were very low and not distinguishable from the controls. In conclusion, differences in the activities of several hydrolases have been found in the sera of healthy pregnant women in comparison to controls.

Increased levels of several lysosomal enzymes in sera from women using oral contraceptives

The activities of eight lysosomal enzymes were measured by spectrophotometric/spectrofluorimetric techniques in the blood sera of 19-24 apparently healthy women using an oral contraceptive (progestin and oestradiol synthetic derivative, desogestrel+ethinyloestradiol) in comparison with 15-16 non-pregnant women not using contraceptives (controls), in a randomised, double-blind, controlled study. beta-Glucuronidase and arylesterase showed statistically increased activities (P < or = 0.05) in the experimental group in comparison to the controls. No significant differences were found for the remaining enzymes assayed (beta-N-acetylhexosaminidase, alpha-L-fucosidase, alpha-mannosidase, beta-galactosidase, alpha-galactosidase and acid phosphatase). Similar results were obtained when the contraceptive formed by the combination of levonorgestrel and ethinyloestradiol was used by an experimental group of eight healthy women. These results suggest that the significant increases in the above-mentioned activities might be the physiological response of the organism (through catabolic processes catalysed by lysosomal enzymes) to the administration of exogenous synthetic compounds, such as the oral contraceptives used.

Biochemical and toxicological studies on the effect of high and low erucic acid rapeseed oil on rats

Rats were fed on diets containing rapeseed oil, either containing low or high erucic acid content as well as the hydrogenated ones for 6 weeks. Body weight gain, biochemical and pathological parameters were investigated. The data showed high body weight gain for rats fed diets containing low erucic rape oil (LERo) compared with those fed either the high erucic rape oil (HERo), the hydrogenated or the partially hydrogenated oil diets. All rats showed non significant changes for total lipids, total cholesterol, GPT and GOT, except the partially hydrogenated rape oil diet which showed significant decrease for total cholesterol. Alkaline phosphatase however showed a significant decrease, while plasma phospholipids showed significant increase in rats fed on the hydrogenated oil diet. Triglycerides indicated non significant increase except in the group that received low erucic rape oil diet. Histopathological study showed changes in all tissues examined (liver and kidney).

Lysosomal enzyme activities in liver and sera from guinea pigs fed oil related to the toxic oil syndrome

beta-N-Acetylglucosaminidase and beta-galactosidase activities were determined in serum and liver from guinea pigs fed "toxic oil" (related to cases of TOS) under different experimental conditions. The results obtained were compared with those of guinea pigs fed non "toxic oil" (case-unrelated oil; controls 1) and animals fed no oil (controls 2). In serum, both activities were significantly increased after all treatments with case-related oil as compared with controls 1 and 2. In the liver, beta-galactosidase activity did not show significant differences in any of the treatments when compared with controls 2. However, NAG activity decreased significantly after 7 days of treatment with non-heated oil--either case-related or not--when compared with controls 2; it also decreased significantly after 28 days of treatment with heated case-unrelated oil, both with respect to controls 2 and the animals fed case-related oil. Liver weights tended to increase in the animals fed oil--toxic or not--with respect to those of the livers from untreated animals. Morphologically, a slight vacuolization of the hepatocytes was observed in some of the samples from the treated animals.

Alpha-L-fucosidase as a serum marker of hepatocellular carcinoma in southern African blacks

The purpose of this study was to compare alpha-L-fucosidase and alpha-fetoprotein as serum markers of hepatocellular carcinoma in 72 southern African blacks with this tumour and 64 matched patients with benign hepatic diseases which might be mistaken clinically for hepatocellular carcinoma. Alpha-L-fucosidase activity was assayed using p-nitrophenyl-L-fucopyranoside (pNpf) as a substrate and alpha-fetoprotein concentrations were measured by radioimmunoassay. Serum alpha-L-fucosidase activity in the patients with hepatocellular carcinoma (mean 1,268, s.e.m. +/- 83.7, median 1,150 and range 38-3,698 nmol pNpf ml-1 h-1) was significantly higher than that in the matched controls (mean 798, s.e.m. +/- 65.8, median 648 and range 273-3,825 nmol pNpf ml-1 h-1) (P = 0.0001). However, alpha-L-fucosidase was both less sensitive (75 versus 87%) and less specific (70 versus 87%) than alpha-fetoprotein as a serum marker of hepatocellular carcinoma. When, in an endeavour to eliminate false-positive results, the diagnostic cut-off level for alpha-L-fucosidase was increased to 1,500 nmol pNpf ml-1 h-1 and for alpha-fetoprotein to 400 ng ml-1, the sensitivity of alpha-L-fucosidase fell to 21% whereas that of alpha-fetoprotein remained satisfactory at 78%. If the two markers were used together, the number of false-negative alpha-fetoprotein results was reduced from 13 to 5.5%. We conclude that alpha-L-fucosidase is less useful than alpha-fetoprotein as a single marker of hepatocellular carcinoma in southern African blacks. However, the two markers can profitably be used together.

Glycosidase activities in sera from convalescent patients who ingested a toxic oil

Some glycosidase activities have been determined in blood sera from 21 patients who ingested a toxic oil (rapeseed oil denatured with aniline(s) and treated by a thermal process). The samples were collected from the same patients on 3 or 4 occasions during a period of 11-12 mth. During this period, the clinical state of the patients improved and, generally, they were restored to health. beta-N-Acetylglucosaminidase, alpha-L-fucosidase, beta-D-glucuronidase, beta-D-glucosidase and alpha-D-mannosidase activities, which were higher in patients than in 17 controls during the first mth decreased to normal values in the period studied, 11-12 mth. In contrast, beta-D-galactosidase, alpha-D-galactosidase and alpha-D-glucosidase activities, which were initially lower in patients than in controls, were finally similar or higher than in controls. One explanation for these results could be the possible alteration of the cell membrane(s) by the toxic substance(s).

Purification, characterization and kinetics of beta-N-acetylhexosaminidases A and B from the slug Arion rufus L

Two beta-N-acetylhexosaminidases have been purified to homogeneity and characterized, from the digestive gland of the slug A. rufus L., showing very high specific activities. Hexosaminidase A (Hex A) was purified 1300-fold with a yield of 12%, and hexosaminidase B (Hex B) was purified 1400-fold with a yield of 20%. Purified Hex A or Hex B run as a single protein band in polyacrylamide gel disc electrophoresis, showing different mobilities. The purified preparations do not show any of the other glycosidase activities present in the crude extract. beta-N-acetylglucosaminidase (GlcNAc-ase) and beta-N-acetylgalactosaminidase (GalNAc-ase) activities are always associated in a single peak for each enzyme form, with constant activity ratio, in all the purification steps, since they are catalyzed by the same enzyme (Hex A or Hex B). The optimal pH for both forms are 4.5 for GlcNAc-ase and 4.0 for GalNAc-ase activity. Hex B shows thermal and pH-stability higher than Hex A. The isoelectric points are 4.5 and 5.5 for A and B forms, respectively. The molecular weight is 150 000 for Hex A and 320 000 for Hex B. The amino acid composition of purified Hex A and B presents some differences concerning particularly Cys, Thr, Ser, Glu and Ile. The ratios Vmax/Km show that GlcNAc-ase is the main activity of both enzyme forms. beta-N-acetylglucosides and beta-N-acetylgalactosides completely compete for a common active site in mixed-substrates experiments. The Ki values are always coincident for GlcNAc-ase and GalNAc-ase activities, using competitive inhibitors (the corresponding lactones). These results strongly suggest that both activities are catalyzed by the same active site in both Hex A and B. Inhibition of the enzyme activities was found with the corresponding lactones, N-acetyl hexosamines, mannose, mannosides, HgCl2 and lead acetate; activation, with ribose, and with some chlorides and sulphates of divalent cations.

Multiple acid phosphatases in avian pectoral muscle--the postmicrosomal supernatant acid phosphatase is elevated in avian dystrophic muscle

There are at least three forms of acid phosphatase in avian pectoralis muscle differing in molecular weight, subcellular location, and response to various substrates and inhibitors. These enzymes are separated by differential sedimentation into postmicrosomal supernatant, lysosomal, and microsomal activities with apparent molecular weights in Triton X-100 of 68,000, 198,000, and 365,000, respectively. All of the enzymes show acid pH optima (pH approximately 5), but the postmicrosomal supernatant form is distinctly different from the other two forms in its resistance to most common phosphatase inhibitors and in its reduced activity against several organic phosphates. Quantitation of these three forms of acid phosphatase in normal and dystrophic avian pectoralis muscle shows that the postmicrosomal supernatant form is significantly elevated in dystrophic muscle; at 33 days ex ovo, 84% of the increased acid phosphatase activity in dystrophic muscle can be attributed to the postmicrosomal supernatant form. The microsomal form is only slightly elevated; the level of the lysosomal form is not altered.