Amyloid-β(1–42) Protofibrils Formed in Modified Artificial Cerebrospinal Fluid Bind and Activate Microglia

Soluble aggregated forms of amyloid-β protein (Aβ) have garnered significant attention recently for their role in Alzheimer’s disease (AD). Protofibrils are a subset of these soluble species and are considered intermediates in the aggregation pathway to mature Aβ fibrils. Biological studies have demonstrated that protofibrils exhibit both toxic and inflammatory activities. It is important in these in vitro studies to prepare protofibrils using solution conditions that are appropriate for cellular studies as well as conducive to biophysical characterization of protofibrils. Here we describe the preparation and characterization of Aβ(1–42) protofibrils in modified artificial cerebrospinal fluid (aCSF) and demonstrate their prominent binding and activation of microglial cells. A simple phosphate/bicarbonate buffer system was prepared that maintained the ionic strength and cell compatibility of F-12 medium but did not contain numerous supplements that interfere with spectroscopic analyses of Aβ protofibrils. Reconstitution of Aβ(1–42) in aCSF and isolation with size exclusion chromatography (SEC) revealed curvilinear β-sheet protofibrils <100 nm in length and hydrodynamic radii of 21 nm. Protofibril concentration determination by BCA assay, which was not possible in F-12 medium, was more accurately measured in aCSF. Protofibrils formed and isolated in aCSF, but not monomers, markedly stimulated TNFα production in BV-2 and primary microglia and bound in significant amounts to microglial membranes. This report demonstrates the suitability of a modified aCSF system for preparing SEC-isolated Aβ(1–42) protofibrils and underscores the unique ability of protofibrils to functionally interact with microglia.     

Genetics of olfactory behavior in Drosophila melanogaster

We have used a behavioral genetic approach to identify six X-linked loci which specify olfaction in Drosophila melanogaster. Mutations in five of these genes lead to partial anosmias affecting responses either to aldehydes (olfA, olfB, olfE and olfF) or to acetate esters (olfC). Only one of the mutants obtained in our screening (olfD) resulted in a insensitivity to several different odorants. olfA, olfE and olfC map close together in a small region of the chromosome between 7C and 7D. The alleles at the olfC locus fall into two phenotypic classes according to their responses to different acetate esters. The two groups of olfC alleles interact in-trans.     

Ferumoxytol Can Be Used for Quantitative Magnetic Particle Imaging of Transplanted Stem Cells

Molecular Imaging and Biology - To evaluate, if clinically translatable ferumoxytol nanoparticles can be used for in vivo detection and quantification of stem cell transplants with magnetic...     

Patterns of Recurrence Following Complete Response to Regional Chemotherapy for In-Transit Melanoma

Background

Even after complete response (CR) to regional chemotherapy for in-transit melanoma, many patients develop recurrence. Understanding the probability, location, and timing of recurrences can optimize management strategies for this patient population.

Methods

A prospective database identified patients who underwent 81 first-time hyperthermic isolated limb perfusions (HILPs) and 133 first-time isolated limb infusions (ILIs). Response was defined using the response evaluation criteria in solid tumors; recurrence was defined as development of new disease after in-field CR.

Results

HILP exhibited a significantly higher CR rate than ILI (44 vs. 28?%, p?=?.01). Among 36 HILP-CRs and 37 ILI-CRs, the 3-year recurrence rate was 65?% (95?% confidence interval [95?% CI]: 43?C79?%) and 85?% (95?% CI: 63?C94%), respectively. Median time to first recurrence was longer for HILP-CR than ILI-CR (23 vs. 8?months, p?=?.02). There was no statistically significant difference in median time to in-field recurrence between HILP-CR and ILI-CR (46 vs. 25?months, p?=?.15), but HILP-CR showed a longer median time to out-of-field recurrence (42 vs. 14?months, p?=?.02). Finally, the overall survival (OS) difference between HILP-CR and ILI-CR (3-year survival: 77 vs. 54?%) did not achieve statistical significance (p?=?.10).

Conclusions

In the largest series comparing patterns of recurrence, we demonstrate that out-of-field recurrence after CR to HILP occurs later than after CR to ILI, though control of in-field disease remains similar. There remains no statistically significant difference in overall survival after CR to the 2 procedures.     

Consistent subtype-specific anti-HIV type 1 T lymphocyte responses in Indian subjects recently infected with HIV type 1

Anti-HIV-1-specific T cell responses in early HIV-1 infection have been found to be important in deciding the course of disease progression. But there are few data concerning nonsubtype B HIV infection. HIV-1 subtype C is the most prevalent subtype in India. HIV-1 Gag-specific T cell responses in 12 Indian subjects with recent HIV-1 infection were characterized by an ELISpot assay at two consecutive visits and their correlation with plasma viral load and CD4(+) T lymphocyte counts was studied. Ten of the 12 subjects demonstrated T cell responses to either one or both Gag B and C peptides, on at least one visit. Five of 10 responders showed a consistent response (response at both visits): 4 exhibited a Gag C-specific consistent response and 1 showed a consistent response to Gag B. The remaining five patients, showing response at only one of the two visits, were considered inconsistent responders. None of the individuals showed a consistent response to both B and C Gag peptides. Marginally significant correlation was observed between consistency of the response and lower plasma viral load (p = 0.062). The subtype-specific Gag C response was also found to be correlated with lower viral load as compared with the response to Gag B (r = -0.336, p = 0.054 for subtype C and r = -0.234, p = 0.13 for subtype B). The data suggest that the patients exhibiting consistent subtype-specific responses to HIV-1 Gag might have better control of viral replication in early HIV infection.