Long-term clinical course of a patient with mucopolysaccharidosis type IIIB / 소아과

Mucopolysaccharidosis type III (MPS III) is a rare genetic disorder caused by lysosomal storage of heparan sulfate. MPS IIIB results from a deficiency in the enzyme alpha-N-acetyl-D-glucosaminidase (NAGLU). Affected patients begin showing behavioral changes, progressive profound mental retardation, and severe disability from the age of 2 to 6 years. We report a patient with MPS IIIB with a long-term follow-up duration. He showed normal development until 3 years. Subsequently, he presented behavioral changes, sleep disturbance, and progressive motor dysfunction. He had been hospitalized owing to recurrent pneumonia and epilepsy with severe cognitive dysfunction. The patient had compound heterozygous c.1444C>T (p.R482W) and c.1675G>T (p.D559Y) variants of NAGLU. Considering that individuals with MPS IIIB have less prominent facial features and skeletal changes, evaluation of long-term clinical course is important for diagnosis. Although no effective therapies for MPS IIIB have been developed yet, early and accurate diagnosis can provide important information for family planning in families at risk of the disorder.

Clinical Value of Renal Dynamic Imaging and Urinary N-Acetyl-?-D-Glucosaminidase,Apoptosis DNA Fragment Detection in Evaluating Damage Degree of Hydronephrotic Kidneys in Children with Hydronephrosis / 实用儿科临床杂志

Objective To explore the clinical value of renal dynamic imaging and urinary N-acetyl-?-D-glucosaminidase(NAG),apoptosis DNA fragment(ADF) in evaluating the damage degree of hydronephrotic kidneys(HnK) in children with hydronephrosis.Methods Level of glomerular filtration rate(GFR) was detected in 41 children with congenital hydronephrosis by renal dynamic imaging,and urine NAG,ADF in pelvis in HnK and healthy kidneys (as controls) were detected by enzyme-linked immuno-sorbent assay(ELISA).Patholo-gic changes of HnK in 41 children were graded intoⅠ~Ⅴ according to Elder standard. And GFR,urinary NAG and ADF of HnK were divi-ded into subgroup according to pathologic changes ,at the same time statistical analysis was performed within each groups. And the correlations of pathologic grades with GFR,urinary NAG and ADF of HnK were analyzed.Results 1.Kindneys GFR in healthy kidneys and Hnk were (174.33?20.43)?10-3 L/min,(143.86?17.51)?10-3 L/min respectinely,and there was significant difference between healthy kidneys and Hnk (P0.05).3.There was significant negative correlation between GFR levels of HnK and pathologic grades(r=-0.814 P0.05).Conclusions For hydronephrotic kidneys,urinary NAG can eva-luate impaired nephric tubule whereas renal dynamic imaging may evaluate the damage level of glomeruli;urine ADF may not indicate the damage level of diseased kidneys in children with congenital hydronephrosis.

Inhibition Kinetics of Acetic Anhydride on Enzyme Activity of β-N-Acetyl-D-glucosaminidase from Pacific White Shrimp ( Penaeus vannamei ) / 中国生物化学与分子生物学报

β- N-Acetyl- D-glucosaminidase ( NAGase, EC3.2.1.52) is a composition of the chitinases and cooperates with endo-chitinase and exo-chitinase to disintegrate chitin into N-acetylglucosamine. Pacific White Shrimp (P. vannamei) NAGase is involved in digestion and molting processes. Some pollutants in seawater affect the enzyme activity causing loss of the biological function of the enzyme, which affects the exuviating shell and threatens the survival of the animal. The effects of acetic anhydride on the enzyme activity for the hydrolysis of pNP-NAG have been studied. The results show that acetic anhydride can lead to reversible non-competitive inhibition at appropriate concentrations, and the IC50 is estimated to be 9.0 mmol/L. The equilibrium constants have been determined for acetic anhydride binding with the enzyme and/or the enzymesubstrate complexes. Inhibition kinetics of acetic anhydride on the enzyme has been studied using the kinetic method of the substrate reaction. The results suggest that at pH 6.2, the action of acetic anhydride on the enzyme is first quick equilibrium binding and then slow inhibition. The microscopic rate constants have been determined for inhibition and reactivation. The results show that k + 0 is much larger than k - 0, indicating the enzyme is completely inactivated at sufficiently large modificator concentration.

Relationship between Malondialdehyde in Renal Cortex and Urinary NAG Activity of Rats exposed to Cadmium

BACKGROUND: To investigate the relationship between malondialdehyde in renal cortex and Urinary NAG activity of rats exposed to cadmium. METHODS: Rats were treated with a single intraperitoneal injection of cadmium (as CdCl2, 1 mg/kg) for cadmium-treated group and 24-hour urine were obtained prior to sacrifice on days 1, 2, 4, 8 and 16 (N=10 per each group), respectively. The concentration of malondialdehyde by thiobarbituric acid reaction and cadmium were measured in the homogenates of renal cortex. Nephrotoxocity indices such as N-acetyl--D-glucosaminidase (NAG) activity, total protein, and 24 hours urine volume, and cadmium concentration were measured in the urine. RESULT: The cadmium injection caused significant increase of cadmium concentration in the renal cortex on days 1 and 2, and in urine on days 1, 2 and 4. NAG activity and total protein concentration in urine were significantly increased on days 1, 2 and 4, and on days 1, 4 and 8, respectively. The peak values of NAG activity and total protein in urine were observed on days 1 and 4, respectively. Significant decrease of 24 hours urinary volume was induced on day 1. These results indicated that cadmium induced acute nephrotoxicity in the rats. Urinary NAG activity was changed earlier and at a higher rate than urinary total protein, which suggest that NAG activity is a more sensitive biological index in terms of early diagnosis of cadmium-induced nephrotoxicity. Renal MDA concentration was significantly increased on day 2 and on day 4, and on day 8, MDA concentration and nephrotoxicity indices except urinary total protein were returned to control level. CONCLUSION: Based on the results obtained as above, it was concluded that the malondialdehyde in renal cortex, product of lipid peroxidation was related with the changes of urinary NAG activity indicating nephrotoxic injury.

Combined Effects of Lead and Cadmium on NAG of Rats' Renal Tubular Epithelial Cells WANG / 环境与健康杂志

Objective To explore the combined effects of lead and cadmium on N-acetyl-?-D-glucosaminidase (NAG) of rats' renal tubular epithelial cells. Methods After extraction, purification, identification and culturing, renal tubular epithelial cells of rats were treated with lead acetate of 0, 0.02, 0. 1, 0.5 mmol/L, cadmium chloride of 0, 0.001, 0.004, 0.02 mmol/ L, and lead-cadmium of 2x2 pattern. NAG leaking out of cells was assessed. Results When cells were solely treated with lead acetate of 0.02 and 0. 1 mmol/ L, NAG activities in experimental groups showed no significant difference compared with that in the control group, but showed significant difference with a dosage of 0.5 mmol/L. When cells were solely treated with cadmium chloride of 0.001 and 0. 004mmol/L, NAG also showed no significant difference compared with that in the control group, while showing a significant difference with a dosage of 0.02 mmol/L. When cells were treated jointly with lead-cadmium of different dosages, NAG was significantly higher than that in the experimental groups treated only with lead or cadmium. Conclusion The combined effects of lead and cadmium led to more NAG leaking out of renal tubular epithelial cells of rats.