Human Amyloid β40 Brain ELISA KIT

1 The beta-secretase BACE1 is one of the enzymes that contribute to the production of the A beta peptide, in vitro and in vivo. JMV1195 was previously shown to inhibit BACE activity in vitro but was unable to block cellular BACE activity. We have designed a new permeable inhibitor, JMV2764 that corresponds to a derivative of JMV1195 to which a penetratin sequence had been added at its N-terminus. We have assessed the ability of JMV2764 to affect BACE1 activity in vitro, and to modify A beta production in various cell systems. 2 Endogenous beta-secretase or BACE1 activities were monitored in vitro by means of two distinct fluorimetric substrates in HEK293 extracts of cells expressing either wild-type beta APP, Swedish mutated beta APP or SPA4CT constructs. A beta 40 recovery was monitored by immunoprecipitation and Western blot analysis. 3 JMV2764 and JMV1195 inhibited endogenous beta-secretase activity of HEK293 cellular homogenates with IC(50)s of 0.8 and 6.6 mu M, respectively. Interestingly, JMV2764 also inhibited beta-secretase activity after preincubation with intact cells while JMV1195 was inactive, indicating that unlike JMV1195, JMV2764 could penetrate into the cells. 4 JMV2764 but not JMV1195 also prevented A beta productionby HEK293 cells overexpressing wildtype and Swedish-mutated beta APP. However, JMV2764 was unable to affect A beta production from cells expressing SPA4CT, a beta APP-derived sequence that does not need beta-secretase to produce A beta. 5 Altogether, we have designed a new cell-permeable BACE1 inhibitor that allows to envision to prevent A beta production in vivo. Work is in progress to assess the potential of these compounds to prevent A beta production in transgenic mice overproducing A beta.

Background: Severe traumatic brain injury (TBI) is a major cause of morbidity and mortality. Reduction of thalamic volumes were seen in upto 80% of patients who survived for more than 3 months after TBI. However, the same may not be true in patients who died earlier following TBI. Aims: To to study the thalamus for evidence of any injury in short term survivors of TBI (<5 days) using immunohistochemistry to look for evidence of acute thalamic injury. Materials and Methods: A cross sectional prospective study was done in which autopsy specimens of short term survivors of TBI (<5 days) were studied for histopathological changes. Results: A total of 16 patients with a mean age of 37.8 years were included in the study. CT scan revealed acute subdural haematoma in 10, contusions in 4 patients, extradural haematoma and depressed fracture in 1 each, and diffuse axonal injury in 1 patient. Seven patients required surgery in the form of a decompressive hemicraniectomy. The histopathological analysis of the bilateral thalami showed evidence of congestion of the cerebral capillaries in 8 patients. Axonal retraction balls were seen in 8 patients, myelin breakdown products were seen in 14 patients and axonal swelling was seen in 14 patients. Conclusions: Thalamic injury is universal in the setting of severe TBI in patients who have decreased survival and may be a significant factor for the poor outcome in these patients.