We assayed plasma activities of beta-galactosidase, beta-hexosaminidase, alpha-fucosidase and alpha-galactosidase involved in degradation of the glycoprotein molecule in 110 insulin-dependent diabetics aged 3-1/2 to 19 years and compared them to a group of normal youngsters. We correlated the plasma enzyme activities with the duration, control and sequelae of insulin-dependent diabetes. Insulin-dependent diabetics had a significantly higher plasma activity of beta-hexosaminidase and alpha-mannosidase (p less than 0.01) and a significantly lower plasma activity of alpha-fucosidase and alpha-galactosidase (p less than 0.01). Of the 5 enzymes studied, only plasma beta-hexosaminidase correlated with fasting and postprandial blood sugar (p less than 0.01), cholesterol and triglycerides (p less than 0.05). Additionally, poor control of diabetes was also associated with a significantly higher plasma beta-hexosaminidase activity (p less than 0.01). Proteinuria or an abnormal Addis count suggestive of renal involvement was associated with various changes in plasma acidic hydrolases. These changes may be related to insulin deficiency rather than hyperglycemia and may be genetically determined.

Adolescent↗

PubMedDate not supplied

Urinary acidic glycohydrolases as an index of kidney damage in juvenile diabetes mellitus.

Two lysosomal glycohydrolases, beta-galactosidase and beta-N-hexosaminidase which have been associated with kidney disease were measured in the urine of 110 youngsters with juvenile diabetes mellitus. The mean enzyme excretions in the diabetic group were intermediate between those of normal youngsters and those with active renal disease. Three youngsters with known kidney disease had elevations comparable to others in the diabetic group but no direct correlation could be shown between enzyme elevations and proteinuria or Addis count abnormalities. Positive correlations were seen between enzyme levels and indices of metabolic balance including blood sugar, cholesterol and triglycerides but not with urine sugar or ketones. Duration and estimated stage and control of diabetes also correlated with the urinary enzymes. These preliminary studies are consistent with the possibility that the excretion of these enzymes reflects the ongoing renal damage which occurs in most juvenile diabetics.

Adolescent↗

PubMedDate not supplied

Role of viscoelastic properties of differentiated SH-SY5Y human neuroblastoma cells in cyclic shear stress injury.

Shear stress and strain lead to neurodegeneration in vivo during head injury, glaucoma, and certain repetitive motion disorders. In vitro, shear stress and strain have been shown to lead to cell injury in a number of models using neurons and neuron-like cells. In the present study we examined the relationship between shear stress, strain, and the extent of cell injury in a cyclic shear stress induced model of cell injury using differentiated SH-SY5Y (human neuroblastoma) cells. Shear stress led to cell strain that increased with increasing stress and diminished upon cessation of shear. Strain rate during cyclic application of shear stress increased by over an order of magnitude from the first to all subsequent cycles, suggesting that the cell and/or its polymer network became more elastic upon cyclic shear stress application. To support this conclusion we measured the degree of cytoskeletal polymerization before and after exposure of cells to cyclic shear stress and found that the fraction of polymerized tubulin in the cell relative to total tubulin decreased by a factor of 2 after six cycles of shear stress. The extent of injury, as indicated by the fraction of cells with fragmented DNA, was three times higher for cyclic shear stress than for steady shear stress and may be related to the change in strain rate and/or cytoskeletal reorganization associated with cyclic stress. These findings may aid in understanding the mechanism by which neurons and neuron-like cells respond to cyclic shear stress and strain and lead to new treatments for disease or injury arising from the exposure of neurons to abnormal cyclic or repetitive stress and strain.

Cell Differentiation↗