Expression, distribution and glutamate uptake activity of excitatory aminoacid transporters in vitro cultures of embryonic rat dorsal root ganglia cells

Glutamate is the major mediator of excitatory signalling in the mammalian central nervous system, but it has recently been shown to play also a role in the transduction of sensory input at the periphery and in peripheral neuropathies. New advances in research have demonstrated that rat peripheral sensory terminals and dorsal root ganglia (DRG) express molecules involved in glutamate signalling, including high-affinity membrane-bound glutamate transporters (Excitatory Aminoacid Transporters, EAATs) and that alterations in their expression and/or functionality can be implicated in several models of peripheral neuropathy, neuropathic pain and hyperalgesia. Since EAATS might represent an interesting target for pharmacological intervention, the knowledge of their distribution and functionality deserves to be improved. Here we describe, through immunofluorescence assays, immunoblotting and beta-counter analysis of (H3) L-glutamate uptake, the expression, distribution and activity of the EAATs in in vitro cultures of embryonic DRG sensory neurons, sensory neurons+satellite cells and satellite cells. In this study we demonstrated that EAATs are expressed in all cultures, but that their distribution recognizes a peculiar pattern for each of them, since EAATs immunolabelling was differentially expressed in the cytoplasm of neuronal or satellite cells. This result was further confirmed by immunoblotting. Moreover, both cell types showed a strong sodium-ATP-dependent (active) glutamate uptake activity. However, the net (i.e. active transport minus passive diffusion) glutamate transport was more marked in neuronal cultures when cells were grown and maintained without satellite cells. These results, that demonstrate that functionally active EAATs can be studied in DRG cell cultures, provide further evidence for a role of glutamatergic transport in the peripheral nervous system and will be useful for testing whether any change occurs in in vitro models of peripheral nervous system damage. This work was supported in part by an unrestricted research grant from the “Fondazione Banca del Monte di Lombardia”

The fundamental role of morphology in experimental neurotoxicology: the example of chemotherapy-induced peripheral neurotoxicity

The peripheral nervous system is a frequent target of toxic agents. The accurate identification of the sites of neurotoxic action through the morphological characterization of reliable in vivo models or in vitro systems can give fundamental clues when investigating the pathogenesis and interpreting the clinical features of drug-induced neuropathy. The morphological approach has been used to investigate almost all the anticancer drugs able to induce chemotherapy-induced peripheral neurotoxicity, i.e. platinum drugs, antitubulins and proteasome inhibitors. No models have ever been described for thalidomide. This review demonstrates that any pathogenetic study on chemotherapy-induced peripheral neurotoxicity must be based on solid morphological observations obtained in reliable animal and in vitro models. This is particularly true in this setting, since the availability of tissues of human origin is extremely limited. In fact, peripheral (generally sural) nerve biopsies are never required for diagnostic purposes in chemotherapy-treated cancer patients, and their use for a purely scientific aim, although potentially very informative, is not ethical. Moreover, several neurotoxic drugs target the dorsal root ganglia neurons, and it is very difficult to obtain high-quality specimens even from early autopsies. It is, therefore, our opinion that an extensive morphological assessment of the in vitro and in vivo effect of any potentially neurotoxic antineoplastic drugs, as well as of neuroprotectant agents, should be taken into consideration right from the earliest stages of their development

Atomistic modelling of entropy driven phase transitions between different crystal modifications in polymers: the case of poly(3-alkylthiophenes)

Polymorphism and related solid-state phase transitions affect the structure and morphology and hence the properties of materials, but they are not-so-well understood. Atomistic computational methods can provide molecular-level insights, but they have rarely proven successful for transitions between polymorphic forms of crystalline polymers. In this work, we report atomistic molecular dynamics (MD) simulations of poly(3-alkylthiophenes) (P3ATs), widely used organic semiconductors to explore the experimentally observed, entropy-driven transition from form II to more common form I type polymorphs, or, more precisely, to form I mesophases. The transition is followed continuously, also considering X-ray diffraction evidence, for poly(3-hexylthiophene) (P3HT) and poly(3-butylthiophene) (P3BT), evidencing three main steps: (i) loss of side chain interdigitation, (ii) partial disruption of the original stacking order and (iii) reorganization of polymer chains into new, tighter, main-chain stacks and new layers with characteristic form I periodicities, substantially larger than those in the original form II. The described approach, likely applicable to other important transitions in polymers, provides previously inaccessible insight into the structural organization and disorder features of form I structures of P3ATs, not only in their development from form II structures but also from melts or solutions

Factors Associated With Severe Gastrointestinal Diagnoses in Children With SARS-CoV-2 Infection or Multisystem Inflammatory Syndrome

Importance Severe gastrointestinal (GI) manifestations have been sporadically reported in children with COVID-19; however, their frequency and clinical outcome are unknown. Objective To describe the clinical, radiological, and histopathologic characteristics of children with COVID-19 presenting with severe GI manifestations to identify factors associated with a severe outcome. Design, Setting, and Participants A multicenter retrospective cohort study (February 25, 2020, to January 20, 2021) enrolled inpatient and outpatient children (aged <18 years) with acute SARS-CoV-2 infection, confirmed by positive real-time reverse-transcriptase–polymerase chain reaction on nasopharyngeal swab or fulfilling the US Centers for Disease Control and Prevention criteria for multisystem inflammatory syndrome in children (MIS-C). The study was conducted by pediatricians working in primary care or hospitals in Italy participating in the COVID-19 Registry of the Italian Society of Pediatric Infectious Diseases. Main Outcomes and Measures The occurrence of severe GI manifestations, defined by a medical and/or radiological diagnosis of acute abdomen, appendicitis (complicated or not by perforation and/or peritonitis), intussusception, pancreatitis, abdominal fluid collection, and diffuse adenomesenteritis requiring surgical consultation, occurring during or within 4 to 6 weeks after infection with SARS-CoV-2 infection. Logistic regression was used to estimate odds ratios (ORs) with 95% CIs of factors potentially associated with severe outcomes. Results Overall, 685 children (386 boys [56.4%]; median age, 7.3 [IQR, 1.6-12.4] years) were included. Of these children, 628 (91.7%) were diagnosed with acute SARS-CoV-2 infection and 57 (8.3%) with MIS-C. The presence of GI symptoms was associated with a higher chance of hospitalization (OR, 2.64; 95% CI, 1.89-3.69) and intensive care unit admission (OR, 3.90; 95% CI, 1.98–7.68). Overall, 65 children (9.5%) showed severe GI involvement, including disseminated adenomesenteritis (39.6%), appendicitis (33.5%), abdominal fluid collection (21.3%), pancreatitis (6.9%), or intussusception (4.6%). Twenty-seven of these 65 children (41.5%) underwent surgery. Severe GI manifestations were associated with the child’s age (5-10 years: OR, 8.33; 95% CI, 2.62-26.5; >10 years: OR, 6.37; 95% CI, 2.12-19.1, compared with preschool-age), abdominal pain (adjusted OR [aOR], 34.5; 95% CI, 10.1-118), lymphopenia (aOR, 8.93; 95% CI, 3.03-26.3), or MIS-C (aOR, 6.28; 95% CI, 1.92-20.5). Diarrhea was associated with a higher chance of adenomesenteritis (aOR, 3.13; 95% CI, 1.08-9.12) or abdominal fluid collection (aOR, 3.22; 95% CI, 1.03-10.0). Conclusions and Relevance In this multicenter cohort study of Italian children with SARS-CoV-2 infection or MIS-C, 9.5% of the children had severe GI involvement, frequently associated with MIS-C. These findings suggest that prompt identification may improve the management of serious complications

Geographic Patterns of Genome Admixture in Latin American Mestizos

The large and diverse population of Latin America is potentially a powerful resource for elucidating the genetic basis of complex traits through admixture mapping. However, no genome-wide characterization of admixture across Latin America has yet been attempted. Here, we report an analysis of admixture in thirteen Mestizo populations (i.e. in regions of mainly European and Native settlement) from seven countries in Latin America based on data for 678 autosomal and 29 X-chromosome microsatellites. We found extensive variation in Native American and European ancestry (and generally low levels of African ancestry) among populations and individuals, and evidence that admixture across Latin America has often involved predominantly European men and both Native and African women. An admixture analysis allowing for Native American population subdivision revealed a differentiation of the Native American ancestry amongst Mestizos. This observation is consistent with the genetic structure of pre-Columbian populations and with admixture having involved Natives from the area where the Mestizo examined are located. Our findings agree with available information on the demographic history of Latin America and have a number of implications for the design of association studies in population from the region

Epidemiology, Clinical Features and Prognostic Factors of Pediatric SARS-CoV-2 Infection: Results From an Italian Multicenter Study

Background: Many aspects of SARS-CoV-2 infection in children and adolescents remain unclear and optimal treatment is debated. The objective of our study was to investigate epidemiological, clinical and therapeutic characteristics of pediatric SARS-CoV-2 infection, focusing on risk factors for complicated and critical disease. Methods: The present multicenter Italian study was promoted by the Italian Society of Pediatric Infectious Diseases, involving both pediatric hospitals and general pediatricians/family doctors. All subjects under 18 years of age with documented SARS-CoV-2 infection and referred to the coordinating center were enrolled from March 2020. Results: As of 15 September 2020, 759 children were enrolled (median age 7.2 years, IQR 1.4; 12.4). Among the 688 symptomatic children, fever was the most common symptom (81.9%). Barely 47% of children were hospitalized for COVID-19. Age was inversely related to hospital admission (p < 0.01) and linearly to length of stay (p = 0.014). One hundred forty-nine children (19.6%) developed complications. Comorbidities were risk factors for complications (p < 0.001). Viral coinfections, underlying clinical conditions, age 5\u20139 years and lymphopenia were statistically related to ICU admission (p < 0.05). Garazzino et al. SARS-CoV-2 in Children and Adolescents Conclusions: Complications of COVID-19 in children are related to comorbidities and increase with age. Viral co-infections are additional risk factors for disease progression and multisystem inflammatory syndrome temporarily related to COVID-19 (MIS-C) for ICU admission

COVID-19 in Infants Less than 3 Months: Severe or Not Severe Disease?

Compared to adults, severe or fatal COVID-19 disease is much less common in children. However, a higher risk for progression has been reported in infants. Different pediatric COVID-19 severity scores are reported in the literature

Optimal Time-Consistent Government Debt Maturity

Abstract: This paper develops a model of optimal debt maturity in which the government cannot issue statecontingent debt. As the literature has established, if the government can perfectly commit to fiscal policy, it fully insulates the economy against government spending shocks by purchasing short-term assets and issuing long-term debt. These positions are quantitatively very large relative to GDP and do not need to be actively managed by the government. Our main result is that these conclusions are not robust when lack of commitment is introduced. Under lack of commitment, large and tilted debt positions are very expensive to finance ex-ante since they ex-post exacerbate the government's problem stemming from a lack of commitment. In contrast, a flat maturity structure minimizes the cost entailed by a lack of commitment, though this structure also limits the ability to insure against shocks and increases the volatility of fiscal policy distortions. We show that the optimal time-consistent maturity structure is nearly flat because reducing average borrowing costs is quantitatively more important for welfare than reducing fiscal policy volatility. Thus, under lack of commitment, the government actively manages its debt positions and can approximate optimal policy by confining its debt instruments to consols