Dual inhibitors of beta-amyloid aggregation and acetylcholinesterase as multi-target anti-Alzheimer drug candidates

Notwithstanding the functional role that the aggregates of some amyloidogenic proteins can play in different organisms, protein aggregation plays a pivotal role in the pathogenesis of a large number of human diseases. One of such diseases is Alzheimer"s disease (AD), where the overproduction and aggregation of the β-amyloid peptide (Aβ) are regarded as early critical factors. Another protein that seems to occupy a prominent position within the complex pathological network of AD is the enzyme acetylcholinesterase (AChE), with classical and non-classical activities involved at the late (cholinergic deficit) and early (Aβ aggregation) phases of the disease. Dual inhibitors of Aβ aggregation and AChE are thus emerging as promising multi-target agents with potential to efficiently modify the natural course of AD. In the initial phases of the drug discovery process of such compounds, in vitro evaluation of the inhibition of Aβ aggregation is rather troublesome, as it is very sensitive to experimental assay conditions, and requires expensive synthetic Aβ peptides, which makes cost-prohibitive the screening of large compound libraries. Herein, we review recently developed multi-target anti-Alzheimer compounds that exhibit both Aβ aggregation and AChE inhibitory activities, and, in some cases also additional valuable activities such as BACE-1 inhibition or antioxidant properties. We also discuss the development of simplified in vivo methods for the rapid, simple, reliable, unexpensive, and high-throughput amenable screening of Aβ aggregation inhibitors that rely on the overexpression of Aβ42 alone or fused with reporter proteins in Escherichia coli.

Traducción comentada de «Management of the Clinically Positive Axilla» y «Management of the Internal Mammary Lymph Nodes», Essentials of Breast Surgery

La transmisión de conocimiento científico constituye una de las necesidades de traducción más importantes; es preciso realizar un estudio sobre la traducción del inglés médico. Este trabajo presenta una traducción inédita de fragmentos de Essentials of Breast Surgery y un análisis de esta jerga mediante un glosario y problemas de traducción.

The N-terminal domain of Plasmodium falciparum circumsporozoite protein represents a target of protective immunity.

The N-terminal domain of the circumsporozoite protein (CSP) has been largely neglected in the search for a malaria vaccine in spite of being a target of inhibitory antibodies and protective T cell responses in mice. Thus, in order to develop this region as a vaccine candidate to be eventually associated with other candidates and, in particular, with the very advanced C-terminal counterpart, synthetic constructs representing N- and C-terminal regions of Plasmodium falciparum and Plasmodium berghei CSP were administered as single or combined formulations in mice. We show that the antisera generated against the combinations inhibit sporozoite invasion of hepatocytes in vitro better than antisera against single peptides. Furthermore, two different P. falciparum CSP N-terminal constructs (PfCS22-110 and PfCS65-110) were recognized by serum samples from people living in malaria-endemic regions. Importantly, recognition of the short N-terminal peptide (PfCS65-110) by sera from children living in a malaria-endemic region was associated with protection from disease. Taken together, these results underline the potential of using such fragments as malaria vaccine candidates.

Cross validation of experts versus registration methods for target localization in deep brain stimulation.

In the last five years, Deep Brain Stimulation (DBS) has become the most popular and effective surgical technique for the treatent of Parkinson's disease (PD). The Subthalamic Nucleus (STN) is the usual target involved when applying DBS. Unfortunately, the STN is in general not visible in common medical imaging modalities. Therefore, atlas-based segmentation is commonly considered to locate it in the images. In this paper, we propose a scheme that allows both, to perform a comparison between different registration algorithms and to evaluate their ability to locate the STN automatically. Using this scheme we can evaluate the expert variability against the error of the algorithms and we demonstrate that automatic STN location is possible and as accurate as the methods currently used.

Tenascin-C is a novel RBPJkappa-induced target gene for Notch signaling in gliomas.

Tenascin-C (TNC) expression is known to correlate with malignancy in glioblastoma (GBM), a highly invasive and aggressive brain tumor that shows limited response to conventional therapies. In these malignant gliomas as well as in GBM cell lines, we found Notch2 protein to be strongly expressed. In a GBM tumor tissue microarray, RBPJk protein, a Notch2 cofactor for transcription, was found to be significantly coexpressed with TNC. We show that the TNC gene is transactivated by Notch2 in an RBPJk-dependent manner mediated by an RBPJk binding element in the TNC promoter. The transactivation is abrogated by a Notch2 mutation, which we detected in the glioma cell line Hs683 that does not express TNC. This L1711M mutation resides in the RAM domain, the site of interaction between Notch2 and RBPJk. In addition, transfection of constructs encoding activated Notch2 or Notch1 increased endogenous TNC expression identifying TNC as a novel Notch target gene. Overexpression of a dominant negative form of the transcriptional coactivator MAML1 or knocking down RBPJk in LN319 cells led to a dramatic decrease in TNC protein levels accompanied by a significant reduction of cell migration. Because addition of purified TNC stimulated glioma cell migration, this represents a mechanism for the invasive properties of glioma cells controlled by Notch signaling and defines a novel oncogenic pathway in gliomagenesis that may be targeted for therapeutic intervention in GBM patients.

Stable masking by H-2Dd cis ligand limits Ly49A relocalization to the site of NK cell/target cell contact.

Ly49A is an inhibitory receptor, which counteracts natural killer (NK) cell activation on the engagement with H-2D(d) (D(d)) MHC class I molecules (MHC-I) on target cells. In addition to binding D(d) on apposed membranes, Ly49A interacts with D(d) ligand expressed in the plane of the NK cells' membrane. Indeed, multivalent, soluble MHC-I ligand binds inefficiently to Ly49A unless the NK cells' D(d) complexes are destroyed. However, it is not known whether masked Ly49A remains constitutively associated with cis D(d) also during target cell interaction. Alternatively, it is possible that Ly49A has to be unmasked to significantly interact with its ligand on target cells. These two scenarios suggest distinct roles of Ly49A/D(d) cis interaction for NK cell function. Here, we show that Ly49A contributes to target cell adhesion and efficiently accumulates at synapses with D(d)-expressing target cells when NK cells themselves lack D(d). When NK cells express D(d), Ly49A no longer contributes to adhesion, and ligand-driven recruitment to the cellular contact site is strongly reduced. The destruction of D(d) complexes on NK cells, which unmasks Ly49A, is necessary and sufficient to restore Ly49A adhesive function and recruitment to the synapse. Thus, cis D(d) continuously sequesters a considerable fraction of Ly49A receptors, preventing efficient Ly49A recruitment to the synapse with D(d)+ target cells. The reduced number of Ly49A receptors that can functionally interact with D(d) on target cells explains the modest inhibitory capacity of Ly49A in D(d) NK cells. This property renders Ly49A NK cells more sensitive to react to diseased host cells.

CD1d-antibody fusion proteins target iNKT cells to the tumor and trigger long-term therapeutic responses.

Despite the well-established antitumor activity of CD1d-restricted invariant natural killer T lymphocytes (iNKT), their use for cancer therapy has remained challenging. This appears to be due to their strong but short-lived activation followed by long-term anergy after a single administration of the CD1d agonist ligand alpha-galactosylceramide (αGC). As a promising alternative, we obtained sustained mouse iNKT cell responses associated with prolonged antitumor effects through repeated administrations of tumor-targeted recombinant sCD1d-antitumor scFv fusion proteins loaded with αGC. Here, we demonstrate that CD1d fusion proteins bound to tumor cells via the antibody fragment specific for a tumor-associated antigen, efficiently activate human iNKT cell lines leading to potent tumor cell lysis. The importance of CD1d tumor targeting was confirmed in tumor-bearing mice in which only the specific tumor-targeted CD1d fusion protein resulted in tumor inhibition of well-established aggressive tumor grafts. The therapeutic efficacy correlated with the repeated activation of iNKT and natural killer cells marked by their release of TH1 cytokines, despite the up-regulation of the co-inhibitory receptor PD-1. Our results demonstrate the superiority of providing the superagonist αGC loaded on recombinant CD1d proteins and support the use of αGC/sCD1d-antitumor fusion proteins to secure a sustained human and mouse iNKT cell activation, while targeting their cytotoxic activity and cytokine release to the tumor site.

Médecine interne et gériatrie en soins aigus: mariage de raison [General internal medicine and geriatrics in the acute care setting: opportunities for collaboration]

The health care system faces a difficult challenge as a result of the demographic evolution. The acute hospital is especially challenged by the steady increase of the elderly population. The collaboration between internal medicine and geriatrics in this setting could prove useful to facilitate the adaptation of the acute care setting and greatly enhance education of the health care professionals. Internists and geriatricians can benefit from each other skills and competencies to develop together new models of acute care that would better match the elderly population needs.

Difficult-to-engage patients: a specific target for time-limited assertive outreach in a Swiss setting.

OBJECTIVE: Assertive community treatment (ACT) failed to develop in Europe, and its efficacy is debated. In Lausanne, Switzerland, ACT focuses on difficult-to-engage patients and aims to facilitate linkage with outpatient care through time-limited interventions. This study aimed to evaluate the applicability and efficiency of time-limited ACT. METHODS: We retrospectively assessed social, clinical, and functional outcomes and motivation for treatment in 75 consecutively seen subjects treated between 2000 and 2002. RESULTS: With 70% of the interventions lasting less than 6 months, we observed significant improvement in most clinical and social problems, in collaboration, in motivation for treatment, and in social network support, despite high baseline levels of clinical and social problems. The number of hospitalizations decreased significantly. CONCLUSIONS: Time-limited ACT is a useful treatment for difficult-to-engage patients with severe clinical and social problems, and it facilitates linkage to care. This narrower target for ACT may facilitate its implementation in Europe.

Target joining of duplicated insertion sequence IS21 is assisted by IstB protein in vitro.

Tandemly repeated insertion sequence IS21, located on a suicide plasmid, promoted replicon fusion with bacteriophage lambda in vitro in the presence of ATP. This reaction was catalyzed in a cell extract containing the 45-kDa IstA protein (cointegrase) and the 30-kDa IstB helper protein of IS21 after both proteins had been overproduced in Escherichia coli. Without IstB, replicon fusion was inefficient and did not produce the 4-bp target duplications typical of IS21.

Safety concerns about CCR5 as an antiviral target.

PURPOSE OF REVIEW: Clinical trials of CCR5 antagonists attest to their efficacy and tolerance in HIV treatment. However, there has been debate on their long-term safety because of the role of CCR5 in innate immunity. This review highlights gaps in our understanding of epidemiology of infections that are modulated by CCR5, in particular, in HIV-infected individuals. RECENT FINDINGS: In the mouse model, CCR5 has a role in the response against pathogens as diverse as Toxoplama gondii, West Nile virus, Mycobacterium tuberculosis, herpes simplex virus, Trypanosoma cruzi, Cryptococcus neoformans, Chlamydia trachomatis, Listeria, and plasmodia. In human cohorts, individuals carrying the defective CCR5Delta32 allele present an increased susceptibility to flavivirus (West Nile virus and tickborne encephalitis virus). The selective pressures that led to the spread of loss-of-function CCR5 mutations in humans (CCR5Delta32), and in mangabeys (CCR5Delta24) are not understood. SUMMARY: The recent availability of CCR5 antagonists has raised concern that genetic, biological, or chemical CCR5 knockout, although beneficial against some pathogens (i.e. HIV), could be deleterious for other processes implicated in pathogen response. The consequences of long-term pharmaceutical intervention on CCR5 should be carefully assessed through rigorous postmarketing surveillance.

Acquisitions thérapeutiques en médecine ambulatoire en 2012 [2012 literature findings in ambulatory internal medicine].

In 2012 several articles reported interesting findings for the ambulatory practice in internal general medicine. A negative rapid test for influenza does not rule out that diagnosis. A test assessing the walking speed in the elderly can help determining who would benefit from antihypertensive therapy. Antibiotic treatment has no benefit for acute uncomplicated rhinosinusitis and diverticulitis. Probiotics can reduce the risk of post-antibiotic diarrhea. Daily coffee intake could reduce mortality. Oral supplementation of calcium can be harmful to the cardiovascular system. Subclinical hyperthyroidism should be treated to prevent cardiovascular complications. Aspirin can prevent recurrences in case of a primary thromboembolic event. Local injection of corticosteroids under ultrasonographic guidance for plantar fasciitis can be a safe treatment. Ibuprofen can prevent acute mountain sickness.

Rhythmic growth explained by coincidence between internal and external cues.

Most organisms use circadian oscillators to coordinate physiological and developmental processes such as growth with predictable daily environmental changes like sunrise and sunset. The importance of such coordination is highlighted by studies showing that circadian dysfunction causes reduced fitness in bacteria and plants, as well as sleep and psychological disorders in humans. Plant cell growth requires energy and water-factors that oscillate owing to diurnal environmental changes. Indeed, two important factors controlling stem growth are the internal circadian oscillator and external light levels. However, most circadian studies have been performed in constant conditions, precluding mechanistic study of interactions between the clock and diurnal variation in the environment. Studies of stem elongation in diurnal conditions have revealed complex growth patterns, but no mechanism has been described. Here we show that the growth phase of Arabidopsis seedlings in diurnal light conditions is shifted 8-12 h relative to plants in continuous light, and we describe a mechanism underlying this environmental response. We find that the clock regulates transcript levels of two basic helix-loop-helix genes, phytochrome-interacting factor 4 (PIF4) and PIF5, whereas light regulates their protein abundance. These genes function as positive growth regulators; the coincidence of high transcript levels (by the clock) and protein accumulation (in the dark) allows them to promote plant growth at the end of the night. Thus, these two genes integrate clock and light signalling, and their coordinated regulation explains the observed diurnal growth rhythms. This interaction may serve as a paradigm for understanding how endogenous and environmental signals cooperate to control other processes.