The Effect of Monomers and of Micellar and Vesicular Forms of Non-ionic Surfactants (Solulan C24 and Solulan 16) on Caco-2 Cell Monolayers

Measurements of transepithelial electrical resistance (TEER), the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) test and monitoring of poly(ethylene glycol) (PEG) transport have been used to study the effects of the non-ionic surfactants Solulan C24 and Solulan 16, either free in solution or as an integral part of niosome bi-layers, on intestinal epithelial cells from man (Caco-2 cell monolayers). The effects on epithelial integrity and on the transport of the hydrophilic drug metformin depend on the concentration of the surfactants. At concentrations above 1% the effect on TEER of the surfactant in niosomal form and free in solution were equivalent whereas cell viability was preserved to a higher concentration of Solulans when the Solulans were present in the niosomal form. It was concluded that the toxic effect of niosomes arises from free surfactant present in the niosome suspension.     

Proximal femoral focal deficiency: radiologic analysis of 49 cases

Proximal femoral focal deficiency, an uncommon congenital anomaly, necessitates early radiologic classification for surgical planning and treatment. Objective radiographic criteria, including femoral length index, acetabular depth index, acetabular angle index, and shape of the proximal femur were determined in 49 patients before cartilaginous ossification of the femoral capital epiphysis; final classification was based on follow-up radiographs or findings at arthrography or surgery. These parameters were analyzed to determine the accuracy and contributions of each in classification. Correct classification into one of three groups was possible in 86% of cases with use of three of the parameters: femoral length index, acetabular depth index, and shape of the proximal femur. The acetabular angle was found to contribute insignificantly to classification. Magnetic resonance imaging, used in only one case, depicted the nonossified cartilaginous femoral capital epiphysis, thus obviating the need for invasive diagnostic procedures and facilitating early classification.     

Human mitochondrial glycerol phosphate dehydrogenase (GPDM) isozymes

• 1 A hydrophobic/phospholipid electrophoretic system has been devised which makes possible the analysis of human mitochondrial glycerol phosphate dehydrogenase (E.C. 1.1.99.5, GPD_M.
• 2 GPD_M has a wide tissue distribution in both adult and foetal life and is active in cultured lymphoblastoid cells and fibroblasts but is absent from red cells.
• 3 The solubilization procedure does not significantly alter the kinetic properties of the enzyme (K_mα-glycerophosphate = 0.04-0.07 m , Km PMS = 0.19-0.35 mm ) but the soluble form is less thermostable.
• 4 Comparisons of physicochemical characteristics, tissue distribution and coenzyme requirement point to a separate genetic determination and low level of evolutionary relatedness between GPD_M and its cytosolic counterpart GPD_s.