N-Acetyl-ß-D-hexosaminidase in gestational diabetes mellitus - a preliminary study.

PURPOSE: N-Acetyl-ß-D-hexosaminidase (HEX) is an exoglycosidase which has been extensively studied and which has been used as a marker for inflammation. It was therefore thought that measurement of the activity of this enzyme might be useful in diagnosing gestational diabetes mellitus (GDM) as this condition is frequently associated with inflammation. The main object of the study was the determination of N-acetyl-ß-D-hexosaminidase activity in women with GDM and 3 months postpartum in comparison with control groups of non-pregnant and healthy pregnant women. MATERIAL AND METHODS: Twenty-five blood serum samples from women with GDM and women 3 months postpartum; 20 blood serum samples from non-pregnant and healthy pregnant women (control groups) were enrolled into the study. Serum was prepared from all blood samples and HEX activity was measured by the method of Chateriee et al. (modified by Zwierz et al). RESULTS: A statistically significantly increase in the activity of HEX in the GDM blood serum was found as compared to the control groups (p<0.05). Further analysis showed a statistically significant decrease in the activity of HEX among postpartum women, but the level of enzyme activity was still above the normal control level in comparison to the control group of nonpregnant healthy women (p<0.05). CONCLUSIONS: Changes in the activity of HEX appear to be involved in the pathogenesis of gestational diabetes mellitus. Determination of HEX activity may have prognostic significance as an early indicator of diabetes mellitus among GDM women in the future.

Activity of N-acetyl-beta-D-hexosaminidase (HEX) and its isoenzymes A and B in human milk during the first 3 months of breastfeeding.

PURPOSE: Milk contains free and bound oligo- and heteropolisaccharides, which protect newborns against pathogens and have nutritional value. N-acetyl-beta-D-hexosaminidase (HEX), the most active lysosomal exoglycosidase, modify and degrade oligo- and heteropolysaccharides. The objective of our study was to determine HEX activity and isoenzymes A and B in the progression of lactation. MATERIAL AND METHODS: Human milk samples were collected from 51 women on the 3rd, 21st and 100th day postpartum. Enzymatic activity was determined the Zwierz et al method modified by Marciniak et al. Protein and lactose concentrations were determined by a MilkoScan 4000 apparatus. RESULTS: The total HEX activity decreased by the 21st day in comparison to the 3rd day, and increased by the 100th day as compared to the 21st day. HEX A activity decreased by the 21st and the 100th day as compared to the 3rd day. HEX B activity decreased by 21st day and has the tendency to decrease by the 100th day as compared to the 3rd day. Protein concentration decreased and the lactose concentration increased in milk taken on the 21st day in comparison to concentration of protein and lactose on the 3rd day. HEX and its isoenzymes' activity significantly correlate with the progression of lactation. At the beginning of lactation, HEX A activity, which releases hexosamines from acidic oligosaccharides, dominates; later, HEX B releases hexosamines from neutral oligosaccharides. CONCLUSIONS: To better understand the degradation of human milk oligosaccharides, it would be useful to investigate and document their detailed structures and evaluate the activity of other exoglycosidases' activity in human breast milk over the course of lactation.

Fucosylation in synovial fluid as a novel clinical marker for differentiating joint diseases--a preliminary study.

OBJECTIVE: To investigate fucosylation of synovial fluid glycoproteins in patients with rheumatoid arthritis (RA), juvenile arthritis (JIA), gonarthrosis (GA) and reactive arthritis (ReA), referred to traumatized knee (TK). METHODS: Synovial fluid glycoproteins were separated by SDS-PAGE and either silver stained or blotted onto nitrocellulose and probed with the fucose-specific Aleuria aurantia lectin. Five bands were chosen for densitometric analysis. Total fucose content and density of fucosylated epitopes were analyzed. RESULTS: Fucose content was elevated in all patient groups and almost all bands, comparing to TK. The density of fucosylated epitopes was increased in the 42-kDa band of RA and JIA cases, and lowered in the 26-kDa band of RA and JIA, but not in GA. In all RA cases FR 42-kDa > FR 26-kDa. The relation was opposite in 8 out of 9 GA cases. CONCLUSION: The density of fucosylated epitopes differs significantly in particular glycoproteins of synovial fluid in joint diseases and may be of potential diagnostic value in differentiating diseases of inflammatory and degenerative origin.

Activity of lysosomal exoglycosidases in saliva of patients with HIV infection.

PURPOSE: The aim of this work was to evaluate the influence of HIV infection on the catabolism of glycoconjugates in the oral cavity, by determination of the activity of lysosomal exoglycosidases in mixed saliva. METHOD: The specific activities of the following exoglycosidases were tested: N-acetyl-beta-hexosaminidase (HEX), its isoenzymes A (HEX-A) and B (HEX-B), alpha-mannosidase (MAN), beta-galactosidase (GAL) and alpha-fucosidase (FUC). RESULT: A significant increase of activity of HEX-A, GAL and FUC, and a significant decrease of the activity of HEX-B was found, but no significant changes in the HEX and MAN activity we noted. CONCLUSION: Our results indicate that following HIV infection, there is probably an increased rate of catabolism of glycoconjugates in saliva resulting from changes in the proportions of the activity of isoenzymes A and B of N-acetyl-beta-hexosaminidase, beta-galactosidase and alpha-fucosidase. An increase of HEXA activity can implicate the beginning of neoplastic changes developing in the oral cavity.

The activity of exoglycosidases in the synovial membrane and knee fluid of patients with rheumatoid arthritis and juvenile idiopathic arthritis.

OBJECTIVE: To determine the activities of the five exoglycosidases that catabolize glycoconjugates (proteoglycans, glycoproteins, and glycolipids) in the synovial membrane and knee joint fluid of patients with rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA). METHODS: The following exoglycosidases were analysed with the p-nitrophenyl derivatives of appropriate sugars as substrates: hexosaminidase (HEX) and its isoenzymes A and B, beta-glucuronidase, beta-galactosidase, alpha-mannosidase, and alpha-fucosidase. RESULTS: Our results show that the activity of all exoglycosidases tested in the synovial membrane of patients with RA and JIA was significantly higher than in synovial fluid. We demonstrated that only the enzymatic activity of HEX was significantly higher in the tissue of patients with inflammatory diseases in comparison to the activity in the control group. CONCLUSION: These data support the concept that the synovial cells of patients with RA and JIA are the main source of exoglycosidases, which catabolize glycoconjugates of cartilage.

Activity of lysosomal exoglycosidases in human gliomas.

There is a lot of data suggesting that modifications of cell glycoconjugates may be important in progression of cancer. In the present work we studied activities of lysosomal exoglycosidases: beta-hexosaminidase and its isoenzymes A and B, beta-galactosidase and alpha-mannosidase, in human gliomas. Enzyme activity was determined spectrophotometrically based on the release of p-nitrophenol from p-nitrophenyl-derivative of appropriate sugars. The activities of the exoglycosidases tested were significantly higher in malignant glial tumors than in control tissue (normal brain tissue) and non-glial tumors. The highest activities of exoglycosidases were observed in high-grade gliomas, and a positive correlation of enzyme activities and degree of malignancy was noted. Our results suggest that lysosomal exoglycosidases may participate in the progression and dynamical development of glial tumors.

Saliva of patients with Type 1 diabetes: effect of smoking on activity of lysosomal exoglycosidases.

OBJECTIVE: The aim of our study was to evaluate the influence of smoking on the activity of N-acetyl-beta-hexosaminidase (HEX), its isoenzymes A (HEX-A) and B (HEX-B) and beta-galactosidase (GAL), in the saliva of patients with Type 1 diabetes. METHODS: In the supernatant HEX and its isoenzymes A and B, and beta-galactosidase were determined by the method of Chatteriee et al in modification of Zwierz et al (mKat kg(-1) of protein). Protein was determined by the Lowry et al method (mg ml(-1)). RESULTS: The results presented here suggest that diabetes and smoking modify activity of HEX and its isoenzymes, but only combination of diabetes and smoking give a significant increase in the specific activity of HEX and its isoenzymes. CONCLUSIONS: Type 1 diabetes slightly changes the composition of saliva. Smoking cigarettes significantly modifies the composition and properties of saliva in healthy individuals and patients with Type 1 diabetes.

Assessment of salivary levels of the chosen exoglycosidases in patients with aggressive periodontitis after treatment with doxycycline.

PURPOSE: The aim of the study was the clinical assessment of the periodontium in patients with aggressive periodontitis (AP) after treatment with doxycycline hyclate. Moreover, an attempt was made to evaluate the effect of the treatment on the salivary concentrations of beta-glucuronidase, HEX, HEX A and HEX B in AP patients. MATERIAL AND METHODS: Sixteen patients with aggressive periodontitis, aged 28-45 years, were enrolled in the study. The patients were treated with a doxycycline hyclate preparation (Periostat) for 2 months at a dose of 20 mg twice a day. The clinical examination was performed twice, directly prior to pharmacological treatment and after its termination. The following clinical parameters were evaluated: the plaque index (PI), the sulcus bleeding index (SBI), the pocket probing depth (PPD) and the clinical attachment level (CAL). Biochemical determination of beta-glucuronidase, HEX, HEX A and HEX B concentrations in non-stimulated saliva was performed before and after treatment. RESULTS: In AP patients, the values of PI, SBI and CAL before and after treatment were comparable. The mean pocket probing depth before treatment was 3.5 mm, which decreased significantly after treatment (3.2 mm). The values expressed as pKat/kg protein for specific enzymatic activities of HEX, HEX A, HEX B and beta-glucuronidase in the saliva of AP patients before and after doxycycline treatment were similar. CONCLUSIONS: A 2-month treatment with doxycycline is too short to obtain clinical changes. Although the assessment of the activity of such enzymes as beta-glucuronidase, HEX, HEX A and HEX B in the saliva of AP patients allows detection of periodontal inflammation, it cannot be used to determine the risk of its development and therefore has no practical significance.

Activity of N-acetyl-beta-hexosaminidase and its isoenzymes in serum and synovial fluid from patients with different arthropathies.

OBJECTIVE: To evaluate the activity of N-acetyl-Beta-hexosaminidase (HEX) and its isoenzymes in the serum and synovial fluid of healthy volunteers and patients with an injury to the anterior cruciate ligament and/or meniscus (ACL) osteoarthritis (OA), juvenile idiopathic arthritis (JIA) and rheumatoid arthritis (RA). METHODS: The activity of HEX and its isoenzymes was determined according to Zwierz et al. method. Protein content was determined by the biuret method. RESULTS: The specific activity of HEX and its isoenzymes in the serum of patients with JIA showed a tendency to increase in comparison to the reference group. The specific activity of total HEX in the serum of RA patients was significantly increased in comparison to control. Our results show, that specific activity of HEX in synovial fluid, in the reference group 4.2 +/- 0.21 microkat/kg protein (0.25 unit/mg protein), is similar to activity in normal temporomandibular joint fluid (0.3 unit/mg protein). Therefore, we included this group in our research. In patients with OA and ACL injuries, HEX and its isoenzymes showed a tendency to increase in the specific activity in synovial fluid. The specific activity of HEX and its isoenzymes in the synovial fluid of patients with RA and JIA was significantly elevated in comparison to the control and the remaining groups. CONCLUSION: In the synovial fluid of patients with JIA and RA, the specific activity of HEX and its isoenzymes significantly increased in comparison to control and patients with diseases of a non-inflammatory etiology (OA and ACL). In the synovial fluid of control and diseased groups, HEX constituted a higher percent of total proteins than in serum.

Effect of the nitric oxide donor and the nitric oxide synthase inhibitor on the liver of rats with chronic hepatitis induced by dimethylnitrosamine.

The present study was designed to examine the effects of the donor of nitric oxide (NO), NaNO(2) and the inhibitor of NO synthase, N(omega)-nitro-L-arginine (L-NNA), on the development of dimethylnitrosamine (DMNA)-induced chronic hepatitis in rats. L-NNA decreased rat survival and enhanced the severity of hepatic encephalopathy in the DMNA-treated animals. The aggravation of the morphological signs of hepatitis, the activation of serum alanine aminotransferase and cytosolic superoxide dismutase activities and the increase in the liver malondialdehyde content were observed in this group. The treatment with NaNO(2) improved liver morphology, decreased serum marker enzyme activities, lowered the activities of alpha-D-mannosidase and N-acetyl-beta-D-glucosaminidase compared to the DMNA-treated group. The results of the morphological and biochemical studies suggest that L-NNA increased DMNA-induced liver damage, whereas NaNO(2) partially prevented the development of chronic hepatitis. It is proposed that the opposite effects of L-NNA and NaNO(2) are partially explained by a modulation of the free radical-dependent processes in the liver.

The cleavage of vitamin E galactoside in the rat tissue homogenates.

The stability of alpha-tocopheryl beta-galactoside in the presence of endogenous galactosidases in selected tissue homogenates (liver, kidney, ileum and brain) was estimated. High degree release of alpha-tocopherol from alpha-tocopheryl beta-galactoside in tissues of ileum, kidney and brain was observed (82%, 75% and 72%, increase above endogenous alpha-tocopherol, respectively). A possible enzymatic mechanism of the galactoside decomposition was proposed.

The role of mucus and its components in protection and repair within the alimentary tract mucosa: Polish experience.

The Gastroenterology Research Laboratory at New York Medical College, New York City, NY, directed by Prof. Dr. George B. Jerzy Glass and after his retirement by Prof. Dr. Bronislaw L. Slomiany and Prof. Dr. Amalia Slomiany served as a launching pad for successful careers in exploration of mucus for Dr. Andrzej Gindzienski and Dr. Krzysztof Zwierz and Janusz Badurski at the Medical School in Bialystok, Poland as well as Dr. Jerzy Sarosiek at Gastroenterology Research Laboratory, University of Virginia Health Sciences Center, Charlottesville, VA and currently, Gastroenterology Research Laboratory, Kansas University Medical Center, Kansas City, KS, USA. The dynamic and insightful research endeavors implemented at the Medical School of Bialystok revealed new information regarding enzymatic pathways of mucin synthesis especially its carbohydrate components such as hexosamines. These discoveries become instrumental in our understanding of the alimentary tract mucin synthesis and function in health and disease. Similarly innovative mucus research conducted across the Atlantic Ocean uncovered the novelty of mucin elaborated within the esophageal submucosal mucous glands in humans by demonstration that its chemical characteristics are different both from human salivary and gastric mucins. In addition, a novel method for the measurement of the thickness of the gastric mucus layer ex vivo in humans has also been developed. These pioneering works are continued at both mucus exploration centers attracting younger generation of investigators enticed by the mystery of the structure and function of the mucus barrier and its leading role in mucosal protection against injury as well as immediate and unequivocal contribution to mucosal repair and reconstitution process.

[Laboratory diagnosis of ethyl alcohol dependence syndrome]. / Diagnostyka laboratoryjna zespolu uzaleznienia od alkoholu etylowego.

The authors presented the aspects of diagnostics of alcohol dependence paying special attention to its laboratory and biochemical side. Biological sensitive and specific markers of alcohol dependence and abuse: N-acetyl-beta-hexosoaminidase, carbohydrate deficient transferrin and protein-acetaldehyde adducts were also presented.

[Non mucin proteins of saliva with high homology of polypeptide chains]. / Niemucynowe bialka sliny o wysokim stopniu homologii lancucha polipeptydowego.

To non mucin proteins of human saliva belong: cystatins, statherin, histatins and acidic proline-rich protein. These saliva proteins influence hard and soft tissues by forming a pellicle layer on oral mucosa and enamel, by taking part in removing bacteria or initiating of bacterial colonization. Most of them are able to inhibit the formation of dental calculus and control the calcium phosphate homeostasis.

[Alcoholism: biology]. / Alkoholizm--biologia.

This article discusses biochemical changes of ethyl alcohol in human organism, concentrating especially on the negative influence on the metabolism of liver. The authors describe the process of oxidation of alcohol with alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) and emphasize the role of ADH i ALDH isoenzymes in creating individual tolerance of ethanol. Two other ways of ethanol metabolism are also presented. These are: microsomal ethanol oxidation system (MEOS) connected with cytochrome P-450 and peroxisome catalase system. The article also describes the influence of alcohol and its products of metabolism on the structure of liver proteins, on different metabolic processes taking place in this organ, and on the changes in the immunological system in the course of the alcoholic liver disease. Moreover, the authors present some information about the changes in histopathological picture of liver as the result of alcohol abuse.

Disulfide-bound proteolytic fragments of gastric mucin are 100- and 140-kDa proteins.

Pig gastric mucus was tested for its autodegradative proteolytic degradation at pH 7.0, in the presence or absence of proteinase inhibitors and SDS. Samples of crude mucus were incubated at room temperature for 48 and 96 h in sodium azide stabilized buffer, pH 7. 0, and urea-extracted mucin was purified. Electrophoretically homogenic mucin preparation was reduced and alkylated with iodo[(14)C]acetamide, and analyzed for labeled products. On 7.5% SDS/PAGE protein bands at 80 and 120 kDa were noted, but radioactivity was incorporated into 100- and 140-kDa bands, with increasing intensity from T(0) to T(96), and into high molecular mass mucin subunits. The results confirmed the autodegradative properties of gastric mucin and demonstrated that the 100- and 140-kDa fragments are the main proteolytical products of pig gastric mucin and are disulfide bound with the rest of the molecule.

[N-acetyl-beta-glucosaminidase (NAG) activity in parturients with placental insufficiency in postmature pregnancy and with EPH-gestosis]. / Aktywnosc N-acetylo-beta-glukozoaminidazy (NAG) u rodzacych z niewydolnoscia lozyska w ciazy przenoszonej i z EPH-gestoza.

NAG activity evaluation was carried out in parturients' blood and placental homogenates in regular pregnancies (n = 46) and complicated with biological postmaturity (n = 30) and EPH-gestosis (n = 24). It was revealed that in the blood of parturients with pregnancy complicated with gestosis there was considerable increase of NAG activity (2.43 +/- 1.02 microKat/kg). Lower activity level was found in parturients with entopic pregnancy (1.93 +/- 0.87 microKat/kg), and the lowest in those with postmature pregnancy (1.78 +/- 0.56 microKat/kg). The placental homogenates presented statistically significant differences--the highest in postmature pregnancy (6.37 +/- 2.01 mKat/kg), lower in pregnancy complicated with gestosis (4.85 +/- 1.52 mKat/kg) and the lowest in normal pregnancy (3.52 +/- 1.21 mKat/kg). The elevated activity in blood serum of parturient with gestosis may indicate kidney damage in the course of disease. High activity in homogenate may indicate the processes of placental degradation in postmature pregnancy. There is no evidence of correlation between NAG activity in blood and activity in placental tissue.

Structure and biosynthesis of human salivary mucins.

Human salivary glands secrete two types of mucins: oligomeric mucin (MG1) with molecular mass above 1 MDa and monomeric mucin (MG2) with molecular mass of 200-250 kDa. Monomers of MG1 and MG2 contain heavily O-glycosylated tandem repeats located at the central domain of the molecules. MG1 monomers are linked by disulfide bonds located at sparsely glycosylated N- and C-end. MG1 are synthesized by mucous cells and MG2 by the serous cells of human salivary glands.