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.