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NAG Activity (nag + activity)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Characterization of human sperm N -acetylglucosaminidase

INTERNATIONAL JOURNAL OF ANDROLOGY, Issue 3 2008
S. L. Perez Martinez
Summary N -acetylglucosaminidase (NAG) is particularly active in mammalian spermatozoa and appears to be involved in fertilization. Although it is assumed that this enzyme is acrosomal, previous results from our laboratory suggest the presence of NAG at the sperm plasma membrane level. The present study attempted to analyse the subcellular distribution of this enzyme in human spermatozoa. Sperm were incubated under different conditions and NAG activity measured in the soluble extracts and cell pellets using a specific fluorometric substrate. A significant proportion of NAG activity was released when sperm were incubated in culture medium, suggesting a weak association with the plasma membrane. This location was confirmed by western blot analysis of plasma membrane fractions and immunofluorescence on non-permeabilized sperm, which showed a positive signal mainly on the acrosomal domain. The distribution of NAG activity between plasma membrane and acrosome was analysed after cell disruption by freezing and thawing. Triton X-100 stimulated sperm and epididymal NAG activity but not the enzyme obtained from other sources. In addition, biotinylated human recombinant NAG was able to bind to human sperm. Finally, after sperm incubation under capacitating conditions, NAG total activity increased and the sperm enzyme lost its ability to be stimulated by Triton X-100. The possible connection of these results with sperm maturation, capacitation and NAG participation in primary binding to the zona pellucida, was discussed. [source]

Electrophoretic analysis of urinary proteins in diabetic adolescents

JOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 4 2001
George Koliakos
Abstract Pathological changes in the urine sodium dodecyl sulphate gel electrophoresis (SDS PAGE) patterns often precede the occurrence of any sign of renal involvement in diabetes. However, data concerning the most frequent SDS PAGE pattern of the urine in early stages of type I diabetes mellitus are controversial. In the present study an SDS PAGE technique has been used that provides an adequate sensitivity for the detection of the abnormal pattern. Urinary proteins have been analyzed by SDS PAGE in twenty two diabetic adolescents and twenty four age matched controls. Albumin concentration, and N acetyl-beta-D-glucosaminidase (NAG) activity were also measured in the same samples. There was no significant difference in urine albumin concentration and NAG activity between diabetic children and controls. However twelve patients showed an electrophoretic pattern characteristic for glomerulopathy, two had a pattern indicating tubular dysfunction and another two patients had a mixed pattern. Among the twenty four controls only three showed abnormal electrophoretic patterns. The results support the view that early stages of diabetic nephropathy may involve both glomerular and tubular dysfunction. However the exact clinical and prognostic significance of the information provided by SDS PAGE analysis remains to be elucidated. J. Clin. Lab. Anal. 15:178,183, 2001. © 2001 Wiley-Liss, Inc. [source]

Correlation between neutral alpha-glucosidase activity and sperm DNA fragmentation

ANDROLOGIA, Issue 5 2009
M. Watanabe
Summary To evaluate the association between neutral ,-glucosidase (NAG) activity and sperm DNA fragmentation (DFI), ejaculates from 24 men undergoing evaluation for sperm DNA damage as a part of infertility assessment were analysed. The mean ± SD and range for the semen quality of the 24 ejaculates are as follows: volume (3.1 ± 1.3, 1.8,6.0 ml); sperm concentration (45.6 ± 41.1, 1.3,151.2 × 106 ml,1); sperm motility (52.8 ± 28.8, 1,95%); sperm with fragmented DNA (17.6 ± 15.4, 1.7,56.0%); sperm with immature chromatin (9.6 ± 3.8, 2.5,19.1%); NAG activity (37.9 ± 18.3, 4.4,75.3 mU ml,1). The only sperm parameter significantly correlated with neutral ,-glucosidase is the percentage of sperm DFI [correlation coefficient (r) = 0.4376, P = 0.03]. [source]