Increased genomic instability may contribute to the development of kinase domain mutations in chronic myeloid leukemia.

Imatinib resistance in chronic myeloid leukemia (CML) is commonly due to BCR-ABL kinase domain mutations (KDMs). In this single-institution retrospective analysis, patients with KDMs were identified from a cohort of patients treated for CML at our institution. Clinical outcomes were assessed based on the characteristics of the KDMs and results of cytogenetic analysis.

Inhibition of angiogenesis by Abeta peptides.

Abeta peptides are naturally occurring peptides forming beta-sheet aggregates that constitute an integral component of senile plaques and vascular deposits in Alzheimer's disease. Since several peptides adopting a beta-sheet conformation have been shown to be anti-angiogenic, we investigated the effect of Abeta on angiogenesis. We show that in vitro, Abeta dose-dependently inhibits the formation of capillaries by human brain endothelial cells plated on Matrigel and stimulates capillary degeneration at high doses.

Behavioral effects of CD40-CD40L pathway disruption in aged PSAPP mice.

We have shown that, when an amyloid-beta peptide (Abeta) overproducing transgenic mouse model (PSAPP) of Alzheimer's disease (AD) is treated with a depleting antibody against CD40L, it causes marked attenuation of Abeta pathology associated with decreased amyloidogenic processing of amyloid precursor protein (APP) and increased cerebral clearance of Abeta. Here, we report that, when PSAPP mice receive a regimen of anti-CD40L antibody commencing at an age associated with initial Abeta deposition, they demonstrate superior spatial memory on the standard water maze and radial arm water maze tasks, as well as exhibiting superior non-spatial memory in the object recognition test, as compared to control PSAPP mice. Furthermore, PSAPP mice treated with an anti-CD40L antibody regimen commencing at an age associated with extensive Abeta deposition demonstrate superior spatial memory on the standard water maze task, as compared to control PSAPP mice.

Nilvadipine antagonizes both Abeta vasoactivity in isolated arteries, and the reduced cerebral blood flow in APPsw transgenic mice.

The development of Alzheimer's disease (AD) is generally thought to correlate with cerebral accumulation of Abeta. It has previously been shown that Abeta peptides enhance vasoconstriction in isolated arteries and oppose certain vasorelaxants. Moreover, exogenous application of Abeta peptides causes cerebral vasoconstriction in rodents and in transgenic mouse models of AD that overexpress Abeta there is reduced cerebral blood flow.

Increased TNFalpha production and Cox-2 activity in organotypic brain slice cultures from APPsw transgenic mice.

beta-Amyloid (Abeta) peptides are the principal component of senile plaques and vascular deposits in Alzheimer's disease and are derived from the proteolytic cleavage of the beta-amyloid precursor protein (APP). We have previously shown that synthetic Abeta can stimulate cyclooxygenase-2 (Cox-2) activity in brain organotypic slice cultures. In the present study, we used brain slices from transgenic APP Swedish (TgAPPsw) mice and control littermates of different age groups to determine the effect of APP overexpression on the levels of prostaglandin and tumor necrosis factor alpha (TNFalpha) release.

Vasoactive effects of A beta in isolated human cerebrovessels and in a transgenic mouse model of Alzheimer's disease: role of inflammation.

A beta peptides are the major protein constituents of Alzheimer's disease (AD) senile plaques and also form some deposits in the cerebrovasculature leading to cerebral amyloid angiopathy and hemorrhagic stroke. Functional vascular abnormalities are one of the earlier clinical manifestations in both sporadic and familial forms of AD. Most of the cardiovascular risk factors (for instance, diabetes, hypertension, high cholesterol levels, atherosclerosis and smoking) constitute risk factors for AD as well, suggesting that functional vascular abnormalities may contribute to AD pathology.

Role of CD40 ligand in amyloidosis in transgenic Alzheimer's mice.

We have shown that interaction of CD40 with CD40L enables microglial activation in response to amyloid-beta peptide (Abeta), which is associated with Alzheimer's disease (AD)-like neuronal tau hyperphosphorylation in vivo. Here we report that transgenic mice overproducing Abeta, but deficient in CD40L, showed decreased astrocytosis and microgliosis associated with diminished Abeta levels and beta-amyloid plaque load. Furthermore, in the PSAPP transgenic mouse model of AD, a depleting antibody against CD40L caused marked attenuation of Abeta/beta-amyloid pathology, which was associated with decreased amyloidogenic processing of amyloid precursor protein (APP) and increased circulating levels of Abeta.

p35/Cdk5 pathway mediates soluble amyloid-beta peptide-induced tau phosphorylation in vitro.

Alzheimer's disease (AD) is pathologically characterized by deposition of amyloid-beta peptides (Abeta) as senile plaques and by the occurrence of neurofibrillary tangles (NFTs) composed primarily of hyperphosphorylated tau protein. Activation of cyclin-dependent kinase 5 (Cdk5) via its potent activator p25 has recently been shown to promote phosphorylation of tau at AD-specific phosphoepitopes, and increased cleavage of p35 to p25 has been demonstrated in AD patients, suggesting that Cdk5 may represent a pathogenic tau protein kinase. We were interested in the potential effect of soluble forms of Abeta on Cdk5-mediated AD-like tau phosphorylation, insofar as previous studies of human biopsies and aged canine and primate brains have shown that dystrophic neurites appear before the formation of neuritic plaques.