Chronic full-band recordings with graphene microtransistors as neural interfaces for discrimination of brain states

Brain states such as sleep, anesthesia, wakefulness, or coma are characterized by specific patterns of cortical activity dynamics, from local circuits to full-brain emergent properties. We previously demonstrated that full-spectrum signals, including the infraslow component (DC, direct current-coupled), can be recorded acutely in multiple sites using flexible arrays of graphene solution-gated field-effect transistors (gSGFETs). Here, we performed chronic implantation of 16-channel gSGFET arrays over the rat cerebral cortex and recorded full-band neuronal activity with two objectives: (1) to test the long-term stability of implanted devices; and (2) to investigate full-band activity during the transition across different levels of anesthesia. First, we demonstrate it is possible to record full-band signals with stability, fidelity, and spatiotemporal resolution for up to 5.5 months using chronic epicortical gSGFET implants. Second, brain states generated by progressive variation of levels of anesthesia could be identified as traditionally using the high-pass filtered (AC, alternating current-coupled) spectrogram: from synchronous slow oscillations in deep anesthesia through to asynchronous activity in the awake state. However, the DC signal introduced a highly significant improvement for brain-state discrimination: the DC band provided an almost linear information prediction of the depth of anesthesia, with about 85% precision, using a trained algorithm. This prediction rose to about 95% precision when the full-band (AC + DC) spectrogram was taken into account. We conclude that recording infraslow activity using gSGFET interfaces is superior for the identification of brain states, and further supports the preclinical and clinical use of graphene neural interfaces for long-term recordings of cortical activity.

Regulation of young-adult neurogenesis and neuronal differentiation by neural cell adhesion molecule 2 (NCAM2)

Adult neurogenesis persists in mammals in the neurogenic zones, where newborn neurons are incorporated into preexisting circuits to preserve and improve learning and memory tasks. Relevant structural elements of the neurogenic niches include the family of cell adhesion molecules (CAMs), which participate in signal transduction and regulate the survival, division, and differentiation of radial glial progenitors (RGPs). Here we analyzed the functions of neural cell adhesion molecule 2 (NCAM2) in the regulation of RGPs in adult neurogenesis and during corticogenesis. We characterized the presence of NCAM2 across the main cell types of the neurogenic process in the dentate gyrus, revealing different levels of NCAM2 amid the progression of RGPs and the formation of neurons. We showed that Ncam2 overexpression in adult mice arrested progenitors in an RGP-like state, affecting the normal course of young-adult neurogenesis. Furthermore, changes in Ncam2 levels during corticogenesis led to transient migratory deficits but did not affect the survival and proliferation of RGPs, suggesting a differential role of NCAM2 in adult and embryonic stages. Our data reinforce the relevance of CAMs in the neurogenic process by revealing a significant role of Ncam2 levels in the regulation of RGPs during young-adult neurogenesis in the hippocampus.

DISGUISED INGUINAL HERNIA

Introduction

Liposarcomas are malignant neoplasms that originate in fatty mesenchymal tissue and are the most common histological subtype of soft tissue sarcomas. They account for 1% of solid tumors in adults and are located mainly in the extremities, with the retroperitoneum being the second most frequent location. Given the rarity and aggressiveness of these tumors, it is advisable to establish a multidisciplinary approach towards them in order to improve the prognosis of patients.

Clinical case

Patient who was operated upon on a scheduled and outpatient basis for a left inguinal hernia. During surgery, a preperitoneal tumor was identified that was removed and revealed a high-grade dedifferentiated liposarcoma. In a second surgical act, a tumor mass of about 10 centimeters in length was found, lodged in the left pelvis and contacting sigma, which extended into the inguinal duct and scrotal pouch. Finally, compartment surgery and a left orchiectomy with end-to-end colo-sigmoid anastomosis were performed.

Discussion

Routine examination of the masses contained in the hernial sacs is recommended since, despite their infrequency (<0.1%), cases of liposarcomas that have their origin in the inguinal canal have been described. Surgery for retroperitoneal sarcomas must be compartmental, which requires the inclusion of viscera close to the tumor in the resection. Complete surgical resection R0 is the only potentially curative treatment. Compartment surgery should be performed by expert surgeons in referral centers with multidisciplinary teams to improve the prognosis of these patients.

[Esclerosis multiple. Lactancia. Lactante. Planificacion familiar. Posparto. Tratamiento modificador de la enfermedad.]

INTRODUCTION

Multiple sclerosis mainly affects women of childbearing age, and the pregnancy and postpartum period is of special interest because of the peculiarities of the disease course and the therapeutic consequences that derive from it. During the period of breastfeeding (BF), the choice of treatment strategy must weigh up the well-established benefits of BF for both the newborn and the mother against the safety profile and potential adverse effects on the infant resulting from exposure to disease-modifying drugs transferred through breast milk.

DEVELOPMENT

The study reviews the current evidence on the safety of disease-modifying drugs available for the treatment of multiple sclerosis during the BF period, and gathers data on the transfer of the different drugs into breast milk, as well as the potential adverse effects described in the infant. The drugs of first choice during this period are interferon beta and glatiramer acetate. The rest of the disease modifying drugs are not accepted for use in the BF period according to their summary of product characteristics. However, in recent years, data from studies of clinical practice and case series have been published suggesting that some of these drugs could be used safely during this period.

CONCLUSIONS

Given the recognised health benefits of BF for both mother and infant, exclusive breastfeeding is recommended whenever possible. It is essential to carry out an individualised assessment prior to pregnancy and to evaluate the different treatment options depending on each patient.

The elongation factor eEF1A2 controls translation and actin dynamics in dendritic spines

Synaptic plasticity involves structural modifications in dendritic spines that are modulated by local protein synthesis and actin remodeling. Here, we investigated the molecular mechanisms that connect synaptic stimulation to these processes. We found that the phosphorylation of isoform-specific sites in eEF1A2-an essential translation elongation factor in neurons-is a key modulator of structural plasticity in dendritic spines. Expression of a nonphosphorylatable eEF1A2 mutant stimulated mRNA translation but reduced actin dynamics and spine density. By contrast, a phosphomimetic eEF1A2 mutant exhibited decreased association with F-actin and was inactive as a translation elongation factor. Activation of metabotropic glutamate receptor signaling triggered transient dissociation of eEF1A2 from its regulatory guanine exchange factor (GEF) protein in dendritic spines in a phosphorylation-dependent manner. We propose that eEF1A2 establishes a cross-talk mechanism that coordinates translation and actin dynamics during spine remodeling.

New Partners Identified by Mass Spectrometry Assay Reveal Functions of NCAM2 in Neural Cytoskeleton Organization

Neuronal cell adhesion molecule 2 (NCAM2) is a membrane protein with an important role in the morphological development of neurons. In the cortex and the hippocampus, NCAM2 is essential for proper neuronal differentiation, dendritic and axonal outgrowth and synapse formation. However, little is known about NCAM2 functional mechanisms and its interactive partners during brain development. Here we used mass spectrometry to study the molecular interactome of NCAM2 in the second postnatal week of the mouse cerebral cortex. We found that NCAM2 interacts with >100 proteins involved in numerous processes, including neuronal morphogenesis and synaptogenesis. We validated the most relevant interactors, including Neurofilaments (NEFs), Microtubule-associated protein 2 (MAP2), Calcium/calmodulin kinase II alpha (CaMKIIα), Actin and Nogo. An in silico analysis of the cytosolic tail of the NCAM2.1 isoform revealed specific phosphorylation site motifs with a putative affinity for some of these interactors. Our results expand the knowledge of NCAM2 interactome and confirm the key role of NCAM2 in cytoskeleton organization, neuronal morphogenesis and synaptogenesis. These findings are of interest in explaining the phenotypes observed in different pathologies with alterations in the NCAM2 gene.

Photocontrol of Endogenous Glycine Receptors In Vivo

Glycine receptors (GlyRs) are indispensable for maintaining excitatory/inhibitory balance in neuronal circuits that control reflexes and rhythmic motor behaviors. Here we have developed Glyght, a GlyR ligand controlled with light. It is selective over other Cys-loop receptors, is active in vivo, and displays an allosteric mechanism of action. The photomanipulation of glycinergic neurotransmission opens new avenues to understanding inhibitory circuits in intact animals and to developing drug-based phototherapies.

Determination of Glyphosate and Aminomethylphosphonic Acid in Crops by Capillary Gas Chromatography with Mass-Selective Detection: Collaborative Study

A collaborative study was conducted to validate a method for the determination of glyphosate and aminomethylphosphonic acid (AMPA) in crops. The analytes are extracted from crops with water, and the crude extracts are then subjected to a cation exchange cleanup. The analytes are derivatized by the direct addition of the aqueous extract into a mixture of heptafluorobutanol and trifluoroacetic anhydride. The derivatized analytes are quantitated by capillary gas chromatography with mass-selective detection (MSD). The collaborative study involved 13 laboratories located in 5 countries 12 laboratories returned valid data sets. The crops tested were field corn grain, soya forage, and walnut nutmeat at concentrations of 0.050, 0.40, and 2.0 mg/kg. The study used a split-level pair replication scheme with blindly coded laboratory samples. Twelve materials were analyzed, including 1 control and 3 split-level pairs for each matrix, 1 pair at each nominal concentration. For glyphosate, the mean recovery was 91%, the average intralaboratory variance, the repeatability relative standard deviation (RSDr), was 11%, and the interlaboratory variance, the reproducibility relative standard deviation (RSDR), was 16%. For AMPA, the mean recovery was 87%, the RSDr was 16%, and the RSDR was 25% at mg/kg levels.

Reversible silencing of endogenous receptors in intact brain tissue using 2-photon pharmacology

The physiological activity of proteins is often studied with loss-of-function genetic approaches, but the corresponding phenotypes develop slowly and can be confounding. Photopharmacology allows direct, fast, and reversible control of endogenous protein activity, with spatiotemporal resolution set by the illumination method. Here, we combine a photoswitchable allosteric modulator (alloswitch) and 2-photon excitation using pulsed near-infrared lasers to reversibly silence metabotropic glutamate 5 (mGlu5) receptor activity in intact brain tissue. Endogenous receptors can be photoactivated in neurons and astrocytes with pharmacological selectivity and with an axial resolution between 5 and 10 µm. Thus, 2-photon pharmacology using alloswitch allows investigating mGlu5-dependent processes in wild-type animals, including synaptic formation and plasticity, and signaling pathways from intracellular organelles.

Rationally designed azobenzene photoswitches for efficient two-photon neuronal excitation

Manipulation of neuronal activity using two-photon excitation of azobenzene photoswitches with near-infrared light has been recently demonstrated, but their practical use in neuronal tissue to photostimulate individual neurons with three-dimensional precision has been hampered by firstly, the low efficacy and reliability of NIR-induced azobenzene photoisomerization compared to one-photon excitation, and secondly, the short cis state lifetime of the two-photon responsive azo switches. Here we report the rational design based on theoretical calculations and the synthesis of azobenzene photoswitches endowed with both high two-photon absorption cross section and slow thermal back-isomerization. These compounds provide optimized and sustained two-photon neuronal stimulation both in light-scattering brain tissue and in Caenorhabditis elegans nematodes, displaying photoresponse intensities that are comparable to those achieved under one-photon excitation. This finding opens the way to use both genetically targeted and pharmacologically selective azobenzene photoswitches to dissect intact neuronal circuits in three dimensions.

Regulation of actin dynamics during structural plasticity of dendritic spines: Signaling messengers and actin-binding proteins

Activity-dependent plasticity of synaptic structure and function plays an essential role in neuronal development and in cognitive functions including learning and memory. The formation, maintenance and modulation of dendritic spines are mainly controlled by the dynamics of actin filaments (F-actin) through interaction with various actin-binding proteins (ABPs) and postsynaptic signaling messengers. Induction of long-term potentiation (LTP) triggers a cascade of events involving Ca²⁺ signaling, intracellular pathways such as cAMP and cGMP, and regulation of ABPs such as CaMKII, Cofilin, Aip1, Arp2/3, α-actinin, Profilin and Drebrin. We review here how these ABPs modulate the rate of assembly, disassembly, stabilization and bundling of F-actin during LTP induction. We highlight the crucial role that CaMKII exerts in both functional and structural plasticity by directly coupling Ca²⁺ signaling with F-actin dynamics through the β subunit. Moreover, we show how cAMP and cGMP second messengers regulate postsynaptic structural potentiation. Brain disorders such as Alzheimer's disease, schizophrenia or autism, are associated with alterations in the regulation of F-actin dynamics by these ABPs and signaling messengers. Thus, a better understanding of the molecular mechanisms controlling actin cytoskeleton can provide cues for the treatment of these disorders.

Direct and delayed admissions to ICU in older medical patients

The aims of this retrospective cohort study were to retrieve characteristics and outcomes of older (65+) medical patients who are directly admitted to ICU from the ED and to compare these with those admitted to ICU from a ward. Of 1396 patients, 21 (1.5%) were directly admitted to ICU and 54 (3.9%) after a delay. Blood pressure was lower and respiratory rate higher in the direct than in the delayed group. The direct group had lower mortality (28-day: 19.0 vs. 38.9%, p=0.14; 1-year: 42.9 vs. 66.7%; p=0.06), shorter length-of-stay and returned more frequently to independent living than the delayed group. Only a fraction of older patients are admitted to ICU; directly admitted patients tend to have better outcomes.

Electrostatic Screening of Charged Defects in Monolayer MoS2

Defects in monolayer transition-metal dichalcogenides (TMDCs) may lead to unintentional doping, charge-carrier trapping, and nonradiative recombination. These effects impair electronic and optoelectronic technologies. Here we show that charged defects in MoS₂ monolayers can be effectively screened when they are in contact with an ionic liquid (IL), leading to an increase in photoluminescence (PL) yield by up to two orders of magnitude. The extent of this PL enhancement by the IL correlates with the brightness of each pretreated sample. We propose the existence of two classes of nonradiative recombination centers in monolayer MoS₂: (i) charged defects that relate to unintentional doping and may be electrostatically screened by ILs and (ii) neutral defects that remain unaffected by the presence of ILs.

Photomarking Relocalization Technique for Correlated Two-Photon and Electron Microcopy Imaging of Single Stimulated Synapses

Synapses learn and remember by persistent modifications of their internal structures and composition but, due to their small size, it is difficult to observe these changes at the ultrastructural level in real time. Two-photon fluorescence microscopy (2PM) allows time-course live imaging of individual synapses but lacks ultrastructural resolution. Electron microscopy (EM) allows the ultrastructural imaging of subcellular components but cannot detect fluorescence and lacks temporal resolution. Here, we describe a combination of procedures designed to achieve the correlated imaging of the same individual synapse under both 2PM and EM. This technique permits the selective stimulation and live imaging of a single dendritic spine and the subsequent localization of the same spine in EM ultrathin serial sections. Landmarks created through a photomarking method based on the 2-photon-induced precipitation of an electrodense compound are used to unequivocally localize the stimulated synapse. This technique was developed to image, for the first time, the ultrastructure of the postsynaptic density in which long-term potentiation was selectively induced just seconds or minutes before, but it can be applied for the study of any biological process that requires the precise relocalization of micron-wide structures for their correlated imaging with 2PM and EM.

Therapeutic enquiries about biological agents as a tool to identify safety aspects and patterns of use

Background

Biotechnological agents (BA) are increasingly being used in clinical practice. We aimed to determine, whether enquiries about them to a therapeutic consultation service have also become more frequent, and to describe the information requested in these consultations.

Methods

We retrospectively reviewed 14 104 therapeutic consultations collected in a computerised database between 2000 and 2014. Enquiries about BA (monoclonal antibodies, fusion proteins or cytokine antagonists) were chosen. Information on the type of BA, underlying condition, type of enquiry and affiliation of the enquirer was retrieved and compared with data from consultations about other agents.

Results

During the study period, 365 enquiries about 30 different BA were received. Only 4% of them were received before 2004, while 48.8% were received after 2010. Rituximab, infliximab, adalimumab and etanercept were most frequently enquired about. Agent selection (n=184) and/or adverse effects (n=174) were the most frequent reasons for making an enquiry. Most enquiries about an agent selection were made about an off-label use (n=164), mainly for systemic autoimmune diseases (n=61). Over half of the enquiries about adverse effects were about their teratogenic potential (n=96). Enquiries about BA more often requested an opinion (87.7% vs 77.7%) were made by physicians (89.9% vs 76.9%), from a hospital (81.6% vs 44.5%) and regarded a specific patient (87.4% vs 74.5%).

Conclusions

Therapeutic consultations about BA are increasing. Most of them are related to uncertainties of health professionals regarding any new medicine: their off-label use, actual adverse effects or the teratogenic potential of the involved agents.

Diabetes in patients with HIV: patient characteristics, management and screening

BACKGROUND

As HIV management has become more successful during the past years, non-communicable diseases have become more prevalent among HIV-infected individuals. As a result, more HIV-infected patients die of cardiovascular diseases, with diabetes being one of the main risk factors. This study evaluates screening and management of diabetes among HIV-infected patients in a university hospital in the Netherlands.

METHODS

We examined clinical characteristics, glycaemic control and cardiovascular risk management of HIV-infected patients with coexisting diabetes, and determined the frequency of diabetes screening in those without.

RESULTS

Of 518 HIV-infected patients, 28 had been diagnosed with diabetes (5.4%), mostly (20÷28) after being diagnosed with HIV. Patients with coexisting diabetes were older, had a longer duration of HIV, lower CD4 cell counts and higher body mass index (BMI), and were more likely to use aspirin, statins and antihypertensive medication than those without diabetes (all p < 0.05). HbA1c values were below 7% (53 mmol÷mol) in 54% of patients. Targets for systolic blood pressure (< 140 mmHg), LDL cholesterol (< 2.5 mmol÷l) and BMI (< 25 kg÷m2) were achieved by 82%, 50% and 29% of patients, respectively. Annual ophthalmology examination, screening for microalbuminuria and foot control were rarely performed. Among the patients without known diabetes, diabetes screening during the past year had been performed using (non-fasting) plasma glucose in 56% and HbA1c in 10%, but 42% of patients had not been screened.

CONCLUSION

For HIV-infected individuals with diabetes, glycaemic control and cardiovascular risk management were reasonable, but screening for microvascular complications was rarely performed. Annual diabetes screening of HIV-infected patients was not routine.

Validity of the Montreal Cognitive Assessment and the HIV Dementia Scale in the assessment of cognitive impairment in HIV-1 infected patients

The gold standard for evaluating cognitive impairments in HIV-infected patients is to administer an extensive neuropsychological assessment. This may, however, be time-consuming and hence not always feasible in the clinic. Therefore, several brief screening tools have been developed. This study determined the validity of the Montreal Cognitive Assessment (MoCA) and the HIV Dementia Scale (HDS) in detecting cognitive impairment using both the Frascati and cognitive impairment, no dementia (CIND) criteria to classify cognitive impairment in HIV-1 infected patients. The MoCA, HDS, and an extensive neuropsychological assessment, covering nine cognitive domains, were administered in a group of 102 HIV-infected patients who were all on cART and virologically suppressed for at least 1 year. Results show that the areas under the curve (AUCs) for both the MoCA and the HDS were statistically significant, using both the Frascati and the CIND criteria as gold standard. However, the AUCs for the MoCA and HDS did not differ significantly, regardless of the used classification criteria (Frascati: z = 0.37, p = 0.35; CIND: z = -0.62, p = 0.27). Sensitivity of both the MoCA and HDS were low for the recommended cutoff scores (Frascati: MoCA (<26) = 0.56, HDS (<11) = 0.26; CIND: MoCA (<26) = 0.55, HDS (<11) = 0.36). Cutoff scores with good sensitivity and adequate specificity could not be determined for both screening instruments. Therefore, the HDS and MoCA are not recommended as sole instruments to diagnose HIV-associated cognitive impairment.

Structural and molecular remodeling of dendritic spine substructures during long-term potentiation

Synapses store information by long-lasting modifications of their structure and molecular composition, but the precise chronology of these changes has not been studied at single-synapse resolution in real time. Here we describe the spatiotemporal reorganization of postsynaptic substructures during long-term potentiation (LTP) at individual dendritic spines. Proteins translocated to the spine in four distinct patterns through three sequential phases. In the initial phase, the actin cytoskeleton was rapidly remodeled while active cofilin was massively transported to the spine. In the stabilization phase, cofilin formed a stable complex with F-actin, was persistently retained at the spine, and consolidated spine expansion. In contrast, the postsynaptic density (PSD) was independently remodeled, as PSD scaffolding proteins did not change their amount and localization until a late protein synthesis-dependent third phase. Our findings show how and when spine substructures are remodeled during LTP and explain why synaptic plasticity rules change over time.

Tris(2-pyridylmethyl)amine (TPA) as a membrane-permeable chelator for interception of biological mobile zinc

We report the characterization of tris(2-pyridylmethyl)amine (TPA) as a membrane-permeable zinc chelator for intercepting biological mobile zinc. Compared to N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), TPA chelates zinc with faster kinetics in cuvettes, live cells, and brain slices. TPA also is generally less toxic than TPEN in cell culture. Mechanistic analysis indicates that these improvements arise from both the electronic and steric properties of TPA including weaker metal-binding affinity, lower pKa, and smaller size. These results demonstrate that TPA chelation is a valuable addition to the methodologies available for investigating mobile zinc in biology.

Lactobacillus plantarum CECT7315 and CECT7316 stimulate immunoglobulin production after influenza vaccination in elderly

OBJECTIVE

The effectiveness of influenza vaccination in preventing illness is lower in the elderly; this is why the ability of Lactobacillus plantarum CECT 7315/7316 to stimulate the response to influenza vaccination in elderly was evaluated.

RESEARCH METHODS AND PROCEDURES

A randomized, double-blind, placebo-controlled human trial including 60 institutionalized volunteers aged 65-85 years was performed. All the volunteers were vaccinated with a trivalent influenza vaccine (A/Wisconsin/67/2005 NYMC X-161B (H3N2), A/Solomon Islands/3/2006 (H1N1) and B/Malaysia/2506/2004) for the Spanish vaccine campaign 2006/2007. The consumption of the probiotic began between three and four months after the vaccination. Volunteers were randomly assigned to one of three following groups: group A (receiving 5*10(9) cfu/day of L. plantarum CECT 7315/7316 in 20 g powdered skim milk), group B (receiving 5*10(8) cfu/day of L. plantarum CECT 7315/7316 in 20 g powdered skim milk) and group C or placebo (20 g powered skim milk). The participants consumed the probiotic during 3 months.

RESULTS

The consumption of L. plantarum CECT 7315/7316 during 3 months after influenza vaccination increased the levels of influenza-specific IgA and IgG antibodies. Moreover, a trend towards an increase in influenza-specific IgM antibodies was also observed.

CONCLUSION

L. plantarum CECT7315/7316 has an immunostimulating effect and could be used to improve the response to influenza vaccination in elderly.

Roles of neuronal activity-induced gene products in Hebbian and homeostatic synaptic plasticity, tagging, and capture

The efficiency of synaptic transmission undergoes plastic modification in response to changes in input activity. This phenomenon is most commonly referred to as synaptic plasticity and can involve different cellular mechanisms over time. In the short term, typically in the order of minutes to 1 h, synaptic plasticity is mediated by the actions of locally existing proteins. In the longer term, the synthesis of new proteins from existing or newly synthesized mRNAs is required to maintain the changes in synaptic transmission. Many studies have attempted to identify genes induced by neuronal activity and to elucidate the functions of the encoded proteins. In this chapter, we describe our current understanding of how activity can regulate the synthesis of new proteins, how the distribution of the newly synthesized protein is regulated in relation to the synapses undergoing plasticity and the function of these proteins in both Hebbian and homeostatic synaptic plasticity.

Structural plasticity of dendritic spines

Dendritic spines are small mushroom-like protrusions arising from neurons where most excitatory synapses reside. Their peculiar shape suggests that spines can serve as an autonomous postsynaptic compartment that isolates chemical and electrical signaling. How neuronal activity modifies the morphology of the spine and how these modifications affect synaptic transmission and plasticity are intriguing issues. Indeed, the induction of long-term potentiation (LTP) or depression (LTD) is associated with the enlargement or shrinkage of the spine, respectively. This structural plasticity is mainly controlled by actin filaments, the principal cytoskeletal component of the spine. Here we review the pioneering microscopic studies examining the structural plasticity of spines and propose how changes in actin treadmilling might regulate spine morphology.

Multisensory information facilitates reaction speed by enlarging activity difference between superior colliculus hemispheres in rats

Animals can make faster behavioral responses to multisensory stimuli than to unisensory stimuli. The superior colliculus (SC), which receives multiple inputs from different sensory modalities, is considered to be involved in the initiation of motor responses. However, the mechanism by which multisensory information facilitates motor responses is not yet understood. Here, we demonstrate that multisensory information modulates competition among SC neurons to elicit faster responses. We conducted multiunit recordings from the SC of rats performing a two-alternative spatial discrimination task using auditory and/or visual stimuli. We found that a large population of SC neurons showed direction-selective activity before the onset of movement in response to the stimuli irrespective of stimulation modality. Trial-by-trial correlation analysis showed that the premovement activity of many SC neurons increased with faster reaction speed for the contraversive movement, whereas the premovement activity of another population of neurons decreased with faster reaction speed for the ipsiversive movement. When visual and auditory stimuli were presented simultaneously, the premovement activity of a population of neurons for the contraversive movement was enhanced, whereas the premovement activity of another population of neurons for the ipsiversive movement was depressed. Unilateral inactivation of SC using muscimol prolonged reaction times of contraversive movements, but it shortened those of ipsiversive movements. These findings suggest that the difference in activity between the SC hemispheres regulates the reaction speed of motor responses, and multisensory information enlarges the activity difference resulting in faster responses.

Free fatty acids and the metabolic syndrome in patients with obstructive sleep apnoea

Obesity and metabolic syndrome (MS) occur frequently in patients with obstructive sleep apnoea syndrome (OSAS). We hypothesised that circulating free fatty acids (FFAs) are elevated in OSAS patients independently of obesity. This elevation may contribute to the development of MS in these patients. We studied 119 OSAS patients and 119 controls. Participants were recruited and studied at sleep unit of our institution (Hospital Universitari Son Dureta, Palma de Mallorca, Spain) and were matched for sex, age and body mass index (BMI). The occurrence of MS was analysed by clinical criteria. Serum levels of FFAs, glucose, triglycerides, cholesterol, high-density lipoprotein-cholesterol, aspartate aminotransferase, alanine aminotransferase, γ-glutamyltransferase, C-reactive protein and 8-isoprostanes were determined. Prevalence of MS was higher in OSAS than in the control group (38 versus 21%; p=0.006). OSAS patients had higher FFAs levels than controls (mean±sd 12.2±4.9 versus 10.5±5.0 mg·dL(-1); p=0.015). Among subjects without MS, OSAS patients (OSAS+ MS-) showed higher levels of FFAs than controls (OSAS- MS-) (11.6±4.7 versus 10.0±4.4 mg·dL(-1); p=0.04). In a multiple regression model, after adjustment for age, sex, BMI and the presence of MS, FFAs were significantly associated with apnoea/hypopnoea index (p=0.04). This study shows that FFAs are elevated in OSAS and could be one of the mechanisms involved in the metabolic complications of OSAS.

The roles of CaMKII and F-actin in the structural plasticity of dendritic spines: a potential molecular identity of a synaptic tag?

Ca2+/calmodulin-dependent protein kinase II (CaMKII) and actin are two crucial molecules involved in long-term potentiation (LTP). In addition to its signaling function, CaMKII plays a structural role via direct interaction with actin filaments, thus coupling functional and structural plasticity in dendritic spines. The status of F-actin, regulated by CaMKII, determines the postsynaptic protein binding capacity and thus may act as a synaptic tag that consolidates LTP.

Interstitial telomeric sequences (ITSs) are not located at the exact evolutionary breakpoints in primates

Although their function has not yet been clearly elucidated, interstitial telomeric sequences (ITSs) have been cytogenetically associated with chromosomal reorganizations, fragile sites, and recombination hotspots. In this paper, we show that ITSs are not located at the exact evolutionary breakpoints of the inversions between human and chimpanzee and between human and rhesus macaque chromosomes. We proved that ITSs are not signs of repair in the breakpoints of the chromosome reorganizations analyzed. We found ITSs in the region (0.7-2.7 Mb) flanking one of the two breakpoints in all the inversions assessed. The presence of ITSs in those locations is not by chance. They are short (up to 7.83 repeats) and almost perfect (82.5-97.1% matches). The ITSs are conserved in the species compared, showing that they were present before the reorganizations occurred.

Functional role of the secondary visual cortex in multisensory facilitation in rats

Recent studies reveal that multisensory convergence can occur in early sensory cortical areas. However, the behavioral importance of the multisensory integration in such early cortical areas is unknown. Here, we used c-Fos immunohistochemistry to explore neuronal populations specifically activated during the facilitation of reaction time induced by the temporally congruent audiovisual stimuli in rats. Our newly developed analytical method for c-Fos mapping revealed a pronounced up-regulation of c-Fos expression particularly in layer 4 of the lateral secondary visual area (V2L). A local injection of a GABA A receptor agonist, muscimol, into V2L completely suppressed the audiovisual facilitation of reaction time without affecting responses to unimodal stimuli. Such a selective suppression was not found following the injection of muscimol into the primary auditory and visual areas. To examine whether or not the rats might have shown the facilitated responses because of increment of stimulus intensity caused by the two modal stimuli, the behavioral facilitation induced by the high-intensity unimodal stimuli was tested by the injection of muscimol into V2L, which turned out not to affect the facilitation. These results suggest that V2L, an early visual area, is critically involved in the multisensory facilitation of reaction time induced by the combination of auditory and visual stimuli.

Prostaglandin D synthase (β trace) levels in sleep apnea patients with and without sleepiness

BACKGROUND

Excessive daytime sleepiness (EDS) occurs often in patients with obstructive sleep apnea syndrome (OSAS). However, not all patients present EDS. We hypothesized that the prostaglandin D2 system (PGD2) may be involved in the pathogenesis of EDS associated with OSAS.

METHODS

We measured the levels of lipocalin-type PGD synthase (L-PGDS), the enzyme that produces PGD2, in the serum of 47 patients with OSAS (26 with and 21 without EDS) and 18 healthy controls.

RESULTS

Patients with EDS had higher levels of L-PGDS (0.73+/-0.06 mg/L) than patients without EDS (0.58+/-0.03 mg/L, p<0.05) and controls (0.62+/-0.02 mg/L, p<0.05). L-PGDS levels in patients without EDS and controls were similar.

CONCLUSION

The increased levels of circulating L-PGDS detected in OSAS patients with EDS suggest a possible role of the prostaglandin D system in the pathophysiology of daytime sleepiness in these patients.

Dendritic cell vaccination in combination with TLR-7 agonist, imiquimod, following radio-chemotherapy for newly diagnosed glioblastoma

2021

Background: Standard therapy for glioblastoma, which includes surgery followed by radiation and concurrent chemotherapy, creates a low tumor burden environment that could be ideal for immunotherapeutic approaches. We conducted a Phase I study to assess the safety and immunologic responses of tumor lysate-pulsed dendritic cell (DC) therapy plus topical imiquimod, in combination with standard radio-chemotherapy. Methods: Thirteen patients with newly diagnosed glioblastoma were immunized using autologous tumor lysate-pulsed DC. Each patient initially received 3 immunizations at 2-week intervals, following completion of a 6-week course of radio- chemotherapy. Four patients received 1 million DC, 4 received 5 million, and 5 received 10 million DC per immunization. Patients without tumor progression subsequently received booster vaccinations combined with topical administration of the TLR-7 agonist imiquimod. Immunologic responses to tumor antigens were monitored by HLA-restricted tetramer staining, CTL assays, and quantitation of T-regulatory cells. Clinical tumor growth was monitored by brain MRI scans every 2 months, and the primary clinical endpoint was 2-year survival. Results: All immunizations were well tolerated, with only mild side effects attributable to the DC vaccination and imiquimod adjuvant. Increased levels of CD8+ T cells reactive against tumor antigens, (e.g., gp100, TRP-2, her-2, survivin, and CMV antigens), were detected in 5 patients. Median PFS and OS have not been reached in this trial. To date, 6 of the 13 patients have progressed, and 4 of those have died. The median PFS to date is 18.1 mos. and median OS is 33.8 mos. This compares favorably with controls from the published literature, with a median PFS of 6.9 mos and OS of 14.6 mos. Conclusions: This study demonstrates the safety and clinical/immunologic effects of an autologous tumor lysate-pulsed DC vaccine for patients with newly diagnosed glioblastoma. The adjunctive use of the TLR-7 agonist imiquimod with DC vaccination appears to be non-toxic, and deserves further study. We demonstrate that this active immunotherapy strategy can generate antigen-specific immunologic responses in brain tumor patients following standard radio-chemotherapy.

No significant financial relationships to disclose.