mTOR signaling and its roles in normal and abnormal brain development

Target of rapamycin (TOR) was first identified in yeast as a target molecule of rapamycin, an anti-fugal and immunosuppressant macrolide compound. In mammals, its orthologue is called mTOR (mammalian TOR). mTOR is a serine/threonine kinase that converges different extracellular stimuli, such as nutrients and growth factors, and diverges into several biochemical reactions, including translation, autophagy, transcription, and lipid synthesis among others. These biochemical reactions govern cell growth and cause cells to attain an anabolic state. Thus, the disruption of mTOR signaling is implicated in a wide array of diseases such as cancer, diabetes, and obesity. In the central nervous system (CNS), the mTOR signaling cascade is activated by nutrients, neurotrophic factors, and neurotransmitters that enhances protein (and possibly lipid) synthesis and suppresses autophagy. These processes contribute to normal neuronal growth by promoting their differentiation, neurite elongation and branching, and synaptic formation during development. Therefore, disruption of mTOR signaling may cause neuronal degeneration and abnormal neural development. While reduced mTOR signaling is associated with neurodegeneration, excess activation of mTOR signaling causes abnormal development of neurons and glia, leading to brain malformation. In this review, we first introduce the current state of molecular knowledge of mTOR complexes and signaling in general. We then describe mTOR activation in neurons, which leads to translational enhancement, and finally discuss the link between mTOR and normal/abnormal neuronal growth during development.<br/

TLC-SERS Plates with a Built-In SERS Layer Consisting of Cap-Shaped Noble Metal Nanoparticles Intended for Environmental Monitoring and Food Safety Assurance

Takei H, Saito J, Kato K, Vieker H, Beyer A, Gölzhäuser A. TLC-SERS Plates with a Built-In SERS Layer Consisting of Cap-Shaped Noble Metal Nanoparticles Intended for Environmental Monitoring and Food Safety Assurance. Journal of Nanomaterials. 2015;2015: 316189 .We report on a thin layer chromatograph (TLC) with a built-in surface enhanced Raman scattering (SERS) layer for in-situ identification of chemical species separated by TLC. Our goal is to monitor mixture samples or diluted target molecules suspended in a host material, as happens often in environmental monitoring or detection of food additives. We demonstrate that the TLC-SERS can separate mixture samples and provide in-situ SERS spectra. One sample investigated was a mixture consisting of equal portions of Raman-active chemical species, rhodamine 6 G (R6G), crystal violet (CV), and 1,2-di(4-pyridyl)ethylene (BPE). The three components could be separated and their SERS spectra were obtained from different locations. Another sample was skim milk with a trace amount of melamine. Without development, no characteristic peaks were observed, but after development, a peak was observed at 694 cm(-1). Unlike previous TLC-SERS whereby noble metal nanoparticles are added after development of a sample, having a built-in SERS layer greatly facilitates analysis as well as maintaining high uniformity of noble metal nanoparticles

ER, PgR, Ki67, p27Kip1, and histological grade as predictors of pathological complete response in patients with HER2-positive breast cancer receiving neoadjuvant chemotherapy using taxanes followed by fluorouracil, epirubicin, and cyclophosphamide concomitant with trastuzumab

Patient and tumor characteristics at baseline. (PDF 6 kb

Handheld magnetic probe with permanent magnet and Hall sensor for identifying sentinel lymph nodes in breast cancer patients

Abstract The newly developed radioisotope-free technique based on magnetic nanoparticle detection using a magnetic probe is a promising method for sentinel lymph node biopsy. In this study, a novel handheld magnetic probe with a permanent magnet and magnetic sensor is developed to detect the sentinel lymph nodes in breast cancer patients. An outstanding feature of the probe is the precise positioning of the sensor at the magnetic null point of the magnet, leading to highly sensitive measurements unaffected by the strong ambient magnetic fields of the magnet. Numerical and experimental results show that the longitudinal detection length is approximately 10 mm, for 140 μg of iron. Clinical tests were performed, for the first time, using magnetic and blue dye tracers—without radioisotopes—in breast cancer patients to demonstrate the performance of the probe. The nodes were identified through transcutaneous and ex-vivo measurements, and the iron accumulation in the nodes was quantitatively revealed. These results show that the handheld magnetic probe is useful in sentinel lymph node biopsy and that magnetic techniques are widely being accepted as future standard methods in medical institutions lacking nuclear medicine facilities

BDNF is upregulated by postnatal development and visual experience: quantitative and immunohistochemical analyses

PURPOSE. This study sought to elucidate changes in the levels and distribution of brain-derived neurotrophic factor (BDNF) in the retina throughout aging and depending on visual experience. METHODS. Protein and mRNA levels of BDNF were quantified by enzyme-linked immunosorbent assay (ELISA) and semiquantitative reverse transcription-polymerase chain reaction (RT-PCR), respectively. Levels were assayed in the retinas of rats on postnatal day (P)2, P7, and P14 (approximate time of eye opening) and at 1 month (M), 3M, 8M, and 18M of age. Changes in BDNF expression and localization in the retina were assessed by immunohistochemistry. The effect of monocular deprivation during infancy on retinal BDNF expression was also examined, by ELISA and immunohistochemistry. RESULTS. Both protein and mRNA levels of BDNF in the rat retina increased after P14. Immunohistochemical analyses revealed that the increase in BDNF protein levels occurred in retinal ganglion cells (RGCs) between P14 and 1M. BDNF immunoreactivity in Müller cell processes was observed in the inner nuclear layer at 1M, but not at P14. The levels of BDNF protein in the retinas of visually deprived eyes were lower than those of control eyes, as quantified by ELISA. Immunohistochemistry showed that BDNF immunoreactivity in RGCs was diminished by visual deprivation, whereas Müller cells were unaffected. CONCLUSIONS. These observations indicate that BDNF expression in RGCs is upregulated in an activity-dependent manner, whereas that in Müller cells is regulated only by development. (Invest Ophthalmol Vis Sci. 2003;44:3211-3218) DOI: 10.1167/iovs.02-1089 T he neurotrophin family of ligands contains nerve growth factor, brain-derived neurotrophic factor (BDNF), neurotrophin-3, and neurotrophin-4/5. Neurotrophins and their cognate receptors, TrkA, TrkB, and TrkC, are expressed primarily in neurons to mediate pleiotropic effects, promoting the differentiation, maturation, and survival of neurons in both the peripheral and central nervous systems. 1 Accumulating evidence also suggests that neurotrophins affect synaptic functions. 9 Immunocytochemistry of retinal cell culture revealed that BDNF protein was found primarily in RGCs. 16 The high-affinity BDNF receptor TrkB is also present within the retina. 17,18 TrkB mRNA 10 and protein 11 are detectable in the GCL, inner plexiform layer (IPL), and INL. As neurotrophins and their receptors colocalize in the retina, neurotrophins likely act on retinal neurons in an autocrine and/or paracrine manner. 12 It is thought that the expression of BDNF, but not other neurotrophins, is regulated by neural activity. MATERIALS AND METHODS Animals All experimental procedures using animals were performed in accordance with the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research and the institutional guidelines for care and use of laboratory animals. Male Wistar rats (Japan SLC, Hamamatsu, Japan) were housed in standard lighting conditions (12-hour light-dark cycle) for at least 7 days before experimentation. To examine age-related changes in BDNF protein and mRNA levels in the retina, animals were anesthetized by chloral hydrate and killed by decapitation on postnatal From th

Actin bundling by dynamin 2 and cortactin is implicated in cell migration by stabilizing filopodia in human non-small cell lung carcinoma cells

The endocytic protein dynamin participates in the formation of actin-based membrane protrusions such as podosomes, pseudopodia, and invadopodia, which facilitate cancer cell migration, invasion, and metastasis. However, the role of dynamin in the formation of actin-based membrane protrusions at the leading edge of cancer cells is unclear. In this study, we demonstrate that the ubiquitously expressed dynamin 2 isoform facilitates cell migration by stabilizing F-actin bundles in filopodia of the lung cancer cell line H1299. Pharmacological inhibition of dynamin 2 decreased cell migration and filopodial formation. Furthermore, dynamin 2 and cortactin mostly colocalized along F-actin bundles in filopodia of serum-stimulated H1299 cells by immunofluorescent and immunoelectron microscopy. Knockdown of dynamin 2 or cortactin inhibited the formation of filopodia in serum-stimulated H1299 cells, concomitant with a loss of F-actin bundles. Expression of wild-type cortactin rescued the punctate-like localization of dynamin 2 and filopodial formation. The incubation of dynamin 2 and cortactin with F-actin induced the formation of long and thick actin bundles, with these proteins colocalizing at F-actin bundles. A depolymerization assay revealed that dynamin 2 and cortactin increased the stability of F-actin bundles. These results indicate that dynamin 2 and cortactin participate in cell migration by stabilizing F-actin bundles in filopodia. Taken together, these findings suggest that dynamin might be a possible molecular target for anticancer therapy

Antigen Specificity of Retest Reaction in Contact Sensitivity

Guinea pigs doubly sensitized to 2,4-dinitrochlorobenzene (DNCB) and oxazolone (OX) were tested with DNCB, OX and croton oil and retested by epicutaneous application of DNCB and OX at the sites of prior contact reaction at the various intervals following skin testing. Antigen specificity of retest reaction to DNCB was demonstrated when retest of DNCB was performed 21 and 28 days after the skin testing. The significance of the findings is discussed