Scanning electron microscopy of biosynthetic wound dressings Biocol.

The surface of wound dressing Biocol was studied by scanning electron microscopy. This composite system consists of latex matrix with incorporated water-soluble polysaccharide. The peculiarities of the surface are important for manufacturing of the dressing and for modification of its surface upon contact with fluids, e.g. during de novo tissue reconstruction. The method for studying the fine structure of the polymeric film surface was developed. The relief of the wound dressing changes during interaction with the fluid and nanopores appear on the surface. Thus, scanning electron microscopy is an informative method for studying the surface of biosynthetic films.

Functional, biochemical, and molecular investigations of renal kallikrein-kinin system in diabetic rats.

A reduction of renal kallikrein has been found in non-insulin-treated diabetic individuals, suggesting that an impaired renal kallikrein-kinin system (KKS) contributes to the development of diabetic nephropathy. We analyzed relevant components of the renal KKS in non-insulin-treated streptozotocin (STZ)-induced diabetic rats. Twelve weeks after a single injection of STZ, rats were normotensive and displayed hyperglycemia, polyuria, proteinuria, and reduced glomerular filtration rate. Blood bradykinin (BK) levels and prekallikrein activity were significantly increased compared with controls. Renal kallikrein activity was reduced by 70%, whereas urinary BK levels were increased up to threefold. Renal kininases were decreased as indicated by a 3-fold reduction in renal angiotensin-converting enzyme activity and a 1.8-fold reduction in renal expression of neutral endopeptidase 24.11. Renal cortical expression of kininogen and B2 receptors was enhanced to 1.4 and 1. 8-fold, respectively. Our data suggest that increased urinary BK levels found in severely hyperglycemic STZ-diabetic rats are related to increased filtration of components of the plasma KKS and/or renal kininogen synthesis in combination with decreased renal kinin-degrading activity. Thus, despite reduced renal kallikrein synthesis, renal KKS is activated in the advanced stage of diabetic nephropathy.

Bradykinin excretion is increased in severely hyperglycemic streptozotocin-diabetic rats.

The renal kallikrein-kinin system (KKS) was studied in pair-fed streptozotocin (STZ)-induced diabetic rats and compared with age-matched controls. Twelve weeks after STZ injection, rats were normotensive, showed hyperglycemia, proteinuria, polydipsia and reduced glomerular filtration rate (GFR) and body weight. The activities of urinary prekallikrein (PKLK) and kallikrein (KLK) were reduced accompanied by an up to 3-fold increase of bradykinin (BK) excretion compared to controls. The increased BK excretion suggests that the renal KKS in STZ-diabetes is activated and that the reduction in urinary PKLK and KLK activity may be due to an increased consumption of these enzymes or to a negative feedback mechanism. The stimulation of the renal KKS in STZ-diabetes could reflect an attempt of the organism to balance glomerular hypertension.

The functional effects of biotinylation of anti-angiotensin-converting enzyme monoclonal antibody in terms of targeting in vivo.

The effect of modification with biotin N-hydroxysuccinimide ester of mouse monoclonal antibody to angiotensin-converting enzyme, anti-ACE Mab 9B9, on its targeting to endothelial cells has been studied in vitro and in vivo. By in vitro assay, Mab 9B9 biotinylated at a biotin/IgG molar ratio in reaction mixture (B/IgG ratio) of 0.7-2.2 bound streptavidin monovalently and retained antigen-binding capacity. Mab 9B9 biotinylated at a B/IgG ratio of 20 and higher bound streptavidin polyvalently. Extensive biotinylation (B/IgG ratio of 60 and higher) led to dramatic reduction of Mab 9B9 Ag-binding capacity and to reduction of Mab 9B9 recognition by goat polyclonal antibody to mouse IgG. Radiolabeled Mab 9B9 biotinylated at a B/IgG ratio of 6 (b6-Mab 9B9) bound effectively to cultured vascular endothelium, with affinity characteristics similar to nonbiotinylated Mab 9B9. Endothelial cells internalized both Mab 9B9 and b6-Mab 9B9 to the same extent (60% internalization at 3 h incubation at 37 degrees C). Degradation of cell surface-associated Mab 9B9 or b6-Mab 9B9 was very low (< 1% as measured by TCA solubility of radiolabel). In contrast, degradation of internalized b6-Mab 9B9 was more profound than that of Mab 9B9 (20 +/- 3% vs 6 +/- 1%, P < 0.01). After injection in rats, radiolabeled b6-Mab 9B9 had a biodistribution pattern similar to that of radiolabeled Mab 9B9. Both preparations effectively accumulated in the lung (15-20% of injected dose/g of tissue vs 2% of injected dose/g of blood).(ABSTRACT TRUNCATED AT 250 WORDS)