Breakthrough Bleeding (BTB) is the cause of 50% of discountinuations of use by long-acting progestogen-only contraceptive users. BTB appears to be associated with capilaries of abnormal morphology and fragility. Disturbances in vessles integrity, intercellular junctions or alteration of the basement membrane (BM) composition has been proposed to contribute toward the fragility of these capillaries.In a clinical trial study, thirty-four healthy fertile volunteers were studied before and during use of levonorgestrel releasing subdermal contraceptive implant Norplant. Three endometrial biopcies were taken from each volunteer, one before insertion and two at different time intervals after exposure to Norplant. Then three major components of BM of endometrial vessels, Collagen IV (CIV), laminin and heparan sulphate proteglycan (HSPG) were immunostained and studied. The density of immunostained vessels by each antibody were measured and compared with density of vessels stained by CD34. Double immunostain of CD34 and laminin was also used for demonstration of vessels without BM.Significant decrease in vascular density showing BM components were shown in the study. The density of laminin-, CIV- and HSPG-positive vessels were decreased from 176 ±8, 166± 6.6 and 61± 6 vessels/mm2 (Mean± SEM) in the endometrium of Norplant acceptors before use control samples to 156± 6, 144± 6.2 and 33± 2.9 in the endometrium of Norplant acceptors after 2 to 13 weeks Norplant exposure, respectively (P<0.05). This was occuring at the same time as the overall density of small vessels in Norplant exposed endometrium was showing increase. Significant decrease was also demonstrated over 13 to 42 weeks of use in the densities of laminin and HSPG- positive vessels compared with control (P<0.05), although decrease in the density of CIV positive vessels was not significant.Percentages of vessels showing BM were also calculated in the study. Significant decrease in the percentages of vessels showing BM were demonstrated after 2 to 13 weeks of Norplant use. The percentages of CD34 positive vessels showing laminin-CIV- and HSPG- positive BM in control samples were 97± 3%, 88± 3% and 31± 2% (Mean ±SEM) which significantly decreased to 79 ±3%, 75± 4% and 20± 2% in Norplant users, rspectively (P<0.05).Decrease in the percentage of vessels showing BM was thought to be due to disturbances in the integrity of BM in endometrial vessels of women using Norplant which could be a cause for the fragility of the vessels. The decrease could also be due to decrease in the density of arteriols and increase in the density of venules and appearance of solid cords of endothelial cells. Double immunostaining of the endometrial vessels with anti-CD34 and anti-laminin clearly demonstrated loss of BM or weak staining of BM in the endometrial vessels of Norplant users.Clarification of the local mechanisms which leads to cappilary fragility and abnormal endometrial bleeding may lead to the development of better treatments or prevention and ultimately improve the acceptibility of these contraceptives.

Two forms of Acetylcholinesterase (AChE) could be found in the Wistar rat brain homogenate, soluble and membrane bound enzyme. In order to study and purification of this enzyme, a homogenate of Wistar rat brain was prepared in a phosphate buffer, after centrifugation, supernatant which contains the soluble enzyme was separated. In the second stage the pellet was resuspended in the same volume of phosphate buffer contained Triton X-100 and centrifuged again. The supernatant this time contained the membrane bound enzyme. This enzyme was isotaled and purified using MAP-Agarose.

Sugar cane juice can be better clarified and decolorized by ultra-filtration than by other techniques. In this article application of ultra-filtration in the clarification of cane sugar juice has been described, Several experiments were car­ried out on the raw sugar juice, and decolorization and permeate flux have been studied in this system; furthermore by consideration of different theoretical models, gel layer model have been proposed for this system.

Surfactants are widely used as detergents, emulsifiers, solubilizers, anti-infective and in recent years as absorption enhancers as well. One of the limiting factors in using these agents is their effect on the integrity of biological membranes. In the present study, the membrane disruptive effects of four ionic surfactants, two anionics including sodium lauryl sulfate (SLS) and dioctyl sodium sulfosuccinate (DSS), and two cationics including cetrimide (CET) and benzalkonium chloride (BNZ) were investigated using human red blood cells as a model of biological membrane. It was found that the hemolysis induced by SLS was more pronounced than that of DSS, thus SLS is considered too toxic and may cause permanent damage to the membrane. Also the hemolytic effect of CET was shown to be more than that of BNZ. Thus, BNZ is preferred as a preservative in eye drops. The effect of temperature on the hemolysis caused by the four surfactants was also examined and it was found that increasing the temperature from 25°C to 37° C resulted in a significant increase in the hemolytic effects of all surfactants tested. The results were analysed statistically by T-student test with P<0.05.