Odor Experiences during Preimaginal Stages Cause Behavioral and Neural Plasticity in Adult Honeybees.

In eusocial insects, experiences acquired during the development have long-term consequences on mature behavior. In the honeybee that suffers profound changes associated with metamorphosis, the effect of odor experiences at larval instars on the subsequent physiological and behavioral response is still unclear. To address the impact of preimaginal experiences on the adult honeybee, colonies containing larvae were fed scented food. The effect of the preimaginal experiences with the food odor was assessed in learning performance, memory retention and generalization in 3-5- and 17-19 day-old bees, in the regulation of their expression of synaptic-related genes and in the perception and morphology of their antennae. Three-five day old bees that experienced 1-hexanol (1-HEX) as food scent responded more to the presentation of the odor during the 1-HEX conditioning than control bees (i.e., bees reared in colonies fed unscented food). Higher levels of proboscis extension response (PER) to 1-HEX in this group also extended to HEXA, the most perceptually similar odor to the experienced one that we tested. These results were not observed for the group tested at older ages. In the brain of young adults, larval experiences triggered similar levels of neurexins (NRXs) and neuroligins (Nlgs) expression, two proteins that have been involved in synaptic formation after associative learning. At the sensory periphery, the experience did not alter the number of the olfactory sensilla placoidea, but did reduce the electrical response of the antennae to the experienced and novel odor. Our study provides a new insight into the effects of preimaginal experiences in the honeybee and the mechanisms underlying olfactory plasticity at larval stage of holometabolous insects.

Construction and in vitro testing of a cellulose dura mater graft.

INTRODUCTION: Cerebrospinal fluid (CSF) leaks are a common complication after cranial and spinal surgery and are associated with increased morbidity. Despite continuous research in this field, this problem is far from solved. In this paper, we describe the construction and testing of a bacterial cellulose (BC) membrane as a new dural patch. MATERIALS AND METHODS: The synthesis of BC was performed using Gluconacetobacter hansenii (ATCC 23769) and films were sterilized by autoclaving. The membranes were seeded with human dural fibroblasts. Growth, shape, and cell viability were assessed after 4 weeks. RESULTS: Normally shaped fibroblasts were seen on the BC grafts; confocal microscopy showed cells inside the structure of the mesh. Both viable and nonviable cells were present. Cellular attachment and viability were confirmed by replating of the membranes. DISCUSSION: BC membranes are used in clinical practice to improve skin healing. In the presence of water, they form an elastic, nontoxic, and resistant biogel that can accommodate collagen and growth factors within their structure, thus BC is a good candidate for dural graft construction.

Association between GABA(A) receptor subunit polymorphisms and autism spectrum disorder (ASD).

ASD might be associated with alterations in excitation/inhibition ratio and GABA(A) has been implicated since it mediates synaptic inhibition. Polymorphisms in GABA receptor (GABAR) were studied: significant differences in allele and genotype frequencies observed between cases and controls (rs1912960, GABRA4). Haplotype analysis: rs1912960 (GABRA4) and rs211037 (GABRG2) overrepresented in cases. Rs1912960 has been associated with ASD and rs211037 with epilepsy. GABRA4 is associated with autism in the Argentinean dataset independently or in combination with GABRG2.

Influence of ethnicity on the distribution of genetic polymorphisms associated with risk of chronic liver disease in South American populations.

BACKGROUND: The global burden of chronic liver disease is rising. Besides environmental, behavioral, viral and metabolic factors, genetic polymorphisms in patatin-like phospholipase-3 (PNPLA3) and vitamin D receptor (VDR) genes have been related to the development of chronic liver disease and progression towards liver cancer. Although their prevalence differs remarkably among ethnic groups, the frequency of these polymorphisms in South American populations -whose genetic background is highly admixed- has been poorly studied. Hence, the aim of this study was to characterize polymorphisms related to chronic liver disease and their association with the genetic ancestry of South American populations. RESULTS: DNA samples from 258 healthy unrelated male volunteers were analyzed. The frequencies of G and C alleles of rs738409 polymorphism (PNPLA3 gene) were 74 % and 26 %, respectively; whereas the bAt (CCA) haplotype (VDR gene) was observed in 32.5 % of the samples. The GG genotype of PNPLA3 rs738409 and the bAt (CCA) haplotype -associated with an increased risk of chronic liver disease and progression towards liver cancer- were significantly more frequent among samples exhibiting maternal and paternal Native American haplogroups (63.7 % and 64.6 %), intermediate among admixed samples (45.1 % and 44.9 %; p = 0.03) and the lowest for Non-native American ancestry (30.1 % and 29.6 %; p = 0.001 and p = 0.0008). CONCLUSIONS: These results suggest that individuals with Native American ancestry might have a high risk of chronic liver disorders and cancer. Furthermore, these data not only support the molecular evaluation of ancestry in multi-ethnic population studies, but also suggest that the characterization of these variants in South American populations may be useful for establishing public health policies aimed at high risk ethnic communities.

In Vitro infection of human dura-mater fibroblasts with Staphylococcus aureus: colonization and reactive production of IL-1beta.

OBJECTIVE: Post-operative meningitis, caused mainly by Staphylococcus aureus and Gram-negative rods, is a life-threatening complication after neurosurgery, and its pathogenesis is far from clear. The purpose of this work was to study the experimental infection of human dura-mater fibroblasts and whole human dura by S. aureus. METHODS: In vitro cultures of human dura-mater fibroblasts and organotypic cultures of small pieces of human dura mater were inoculated with a human-derived S. aureus strain. The pattern of bacterial infection as well as cytokines secretion by the infected fibroblasts was studied. RESULTS: Our results suggest that colonisation of human dura-mater fibroblasts in culture and whole dura-mater tissue by S. aureus includes bacterial growth on the cell surface, fibroblast intracellular invasion by bacteria and a significant synthesis of interleukin 1beta (IL-1beta) by the infected cells. CONCLUSION: This is the first report of human dura-mater fibroblast infection by S. aureus. Hopefully, these results can lead to a better understanding of the pathogenesis of meningitis caused by this bacterial species and to a more rational therapeutic approach.

Elevated Hippocampal Cholinergic Neurostimulating Peptide precursor protein (HCNP-pp) mRNA in the amygdala in major depression.

The amygdala is innervated by the cholinergic system and is involved in major depressive disorder (MDD). Evidence suggests a hyper-activate cholinergic system in MDD. Hippocampal Cholinergic Neurostimulating Peptide (HCNP) regulates acetylcholine synthesis. The aim of the present work was to investigate expression levels of HCNP-precursor protein (HCNP-pp) mRNA and other cholinergic-related genes in the postmortem amygdala of MDD patients and matched controls (females: N = 16 pairs; males: N = 12 pairs), and in the mouse unpredictable chronic mild stress (UCMS) model that induced elevated anxiety-/depressive-like behaviors (females: N = 6 pairs; males: N = 6 pairs). Results indicate an up-regulation of HCNP-pp mRNA in the amygdala of women with MDD (p < 0.0001), but not males, and of UCMS-exposed mice (males and females; p = 0.037). HCNP-pp protein levels were investigated in the human female cohort, but no difference was found. There were no differences in gene expression of acetylcholinesterase (AChE), muscarinic (mAChRs) or nicotinic receptors (nAChRs) between MDD subjects and controls or UCMS and control mice, except for an up-regulation of AChE in UCMS-exposed mice (males and females; p = 0.044). Exploratory analyses revealed a baseline expression difference of cholinergic signaling-related genes between women and men (p < 0.0001). In conclusion, elevated amygdala HCNP-pp expression may contribute to mechanisms of MDD in women, potentially independently from regulating the cholinergic system. The differential expression of genes between women and men could also contribute to the increased vulnerability of females to develop MDD.

Xenotrasplante de islotes pancreáticos en el tratamiento de la diabetes insulino dependiente / Xenotransplantation of pancreatic islets in the treatment of insulin-dependent diabetes

La diabetes es una alteración metabólica de elevada incidencia: Su frecuencia aumenta en asociación con la edad. Desatendida genera notable morbilidad. El envejecimiento poblacional otorga interés cardinal al tratamiento de esta patología y una de las propuestas terapéuticas es el trasplante. El homotrasplante brinda resultados promisorios. La parvedad de donantes y la complejidad del procedimiento disminuyen su factibilidad. Se han propuesto diversos xenotrasplantes. Sucinta revisión del estado actual del asunto, en opinión de un experto

Assessing the role of selected growth factors and cytostatic agents in an in vitro model of human dura mater healing.

OBJECTIVES: Cerebrospinal fluid (CSF) leaks are a common concern in skull base surgery. Appropriate dural healing is crucial to prevent CSF leaks but the entire process has been barely understood so far. Here, we review the impact of growth factors and chemotherapeutic agents on an explant culture of human dural fibroblasts and a 3D subculture grown in a collagen mesh scaffold. METHODS: Human dural specimens were harvested during surgical procedures where they would not be further used therapeutically or diagnostically. Explant cultures were grown in Petri dishes, and subcultures were grown in collagen mesh scaffolds. Insulin, fibroblast growth factor type 2 (FGF-2), and human serum were analyzed for their effect as growth factors, whereas mitomycin C, vincristine, and colchicine were analyzed for their role as inhibitors. Cell count was used as a parameter to assess the effects of these factors. In addition, the effects of human serum were assessed using collagen mesh scaffolds. RESULTS: Insulin, FGF-2, and human serum increased culture cell count; human serum also achieved an increased number of viable fibroblasts embedded in a collagen mesh. Mitomycin C, which is a mitosis inhibitor, showed no significant effect on cell count, whereas colchicine and vincristine, which inhibit both mitosis and migration, resulted in cell growth suppression. DISCUSSION: In our model, dural defect closure is achieved through cell migration rather than through cell growth. Adding growth factors to the dural suture line or into a collagen mesh might prove useful to stimulate dural closure.

Skin fibroblasts from patients with type 1 diabetes (T1D) can be chemically transdifferentiated into insulin-expressing clusters: a transgene-free approach.

The conversion of differentiated cells into insulin-producing cells is a promising approach for the autologous replacement of pancreatic cells in patients with type 1 diabetes (T1D). At present, cellular reprogramming strategies encompass ethical problems, epigenetic failure or teratoma formation, which has prompted the development of new approaches. Here, we report a novel technique for the conversion of skin fibroblasts from T1D patients into insulin-expressing clusters using only drug-based induction. Our results demonstrate that skin fibroblasts from diabetic patients have pancreatic differentiation capacities and avoid the necessity of using transgenic strategies, stem cell sources or global demethylation steps. These findings open new possibilities for studying diabetes mechanisms, drug screenings and ultimately autologous transgenic-free regenerative medicine therapies in patients with T1D.

Cognición implícita: un factor para considerar en la educación médica / Implicit cognition: a factor to consider in medical education

La existencia de prejuicios, a menudo inconscientes, es una limitación para la empatía médica y la relación médico-paciente. El término cognición implícita se refiere a las influencias inconscientes (conocimiento previo, percepción y memoria) que, al influir en el comportamiento de las personas, afecta su desempeño o la propia toma de decisiones. A través del aprendizaje, asimilamos la información que nos brinda el medio y nos apropiamos del conocimiento considerando sus distintas dimensiones (conceptos, procedimientos, actitudes y valores). Los mecanismos de aprendizaje implícito son lentos, no suelen ser percibidos conscientemente por las personas y requieren la asociación de los estímulos secuenciales y del almacenamiento de la información concerniente a las relaciones predictivas entre sucesos. Durante el aprendizaje y luego en el ejercicio de la medicina en particular, la existencia de actitudes implícitas negativas relacionadas con el género o las etnias, por ejemplo, podría limitar no solo la adquisición de conocimientos y sus habilidades académicas, sino también el desarrollo de la empatía necesaria durante la atención de los pacientes. La identificación de estas a través del test de asociaciones implícitas (TAI) permitiría caracterizar o predecir las dificultades de aprendizaje a nivel emocional y relacional de los estudiantes. Eso podría ser relevante en la modificación de los planes de estudio para que reciba, durante su formación, las herramientas necesarias para lograr un desempeño adecuado. Este artículo pretende introducir en el campo de la medicina el tema de la cognición implícita asociado a la educación médica.

Evidence for interaction between markers in GABA(A) receptor subunit genes in an Argentinean autism spectrum disorder population.

Autism spectrum disorders (ASD) can be conceptualized as a genetic dysfunction that disrupts development and function of brain circuits mediating social cognition and language. At least some forms of ASD may be associated with high level of excitation in neural circuits, and gamma-aminobutyric acid (GABA) has been implicated in its etiology. Single-nucleotide polymorphisms (SNP) located within the GABA receptor (GABAR) subunit genes GABRA1, GABRG2, GABRB3, and GABRD were screened. A hundred and thirty-six Argentinean ASD patients and 150 controls were studied, and the contribution of the SNPs in the etiology of ASD was evaluated independently and/or through gene-gene interaction using multifactor dimensionality reduction (MDR) method. From the 18 SNP studied, 11 were not present in our Argentinean population (patients and controls) and 1 SNP had minor allele frequency < 0.1%. For the remaining six SNPs, none provided statistical significant association with ASD when considering allelic or genotypic frequencies. Non-significant association with ASD was found for the haplotype analysis. MDR identified evidence for synergy between markers in GABRB3 (chromosome 15) and GABRD (chromosome 1), suggesting potential gene-gene interaction across chromosomes associated with increased risk for autism (testing balanced accuracy: 0.6081 and cross-validation consistency: 10/10, P < 0.001). Considering our Argentinean ASD sample, it can be inferred that GABRB3 would be involved in the etiology of autism through interaction with GABRD. These results support the hypothesis that GABAR subunit genes are involved in autism, most likely via complex gene-gene interactions.

Ingeniería de tejidos y cirugía de la pared abdominal: prototipo de bioprótesis / Tissue engineering and abdominal wall surgery: prototype bioprosthesis

Antecedentes: La tendencia actual es reparar los defectos de la pared abdominal con mallas de polipropileno (PP)Este polímero tiene buena resistencia a las presiones intraabdominales, sin embargo puede presentar adherencias intestinales einfección.Con la idea de evitar estas complicaciones surge el desarrollo de mallas biológicas.Éstas están compuestas de colágeno descelularizado obtenido de tejido conectivo porcino, bovino o humano.Una posibilidad actual es cultivar células madres mesenquimales autólogas sobre las mallas biológicas para que estas últimassirvan de andamio para el desarrollo de las células madre.Así se podría crear una malla híbrida bioartificial compuesta por una malla de polipropileno y una malla biológica cultivada concélulas madres autólogas del propio paciente.De esta forma el componente de polipropileno aportaría resistencia y la malla biológica cultivada con células madres podría aportarcapacidad antiinflamatoria, inmunomoduladora y regeneradora de tejido, así como disminuir las adherencias intestinales, fístulasenterocutáneas e infecciones.La hipótesis de trabajo es que un componente biológico mixto compuesto de una matriz biológica extracelular xenogeneica asociadaa células madre mesenquimales autólogas podría disminuir las reacciones inflamatorias tisulares y adherencias intestinalesque generan las mallas de polipropileno...

Background: The current trend is to repair large abdominal wall defects with polypropylene mesh (PP). This polymer has goodresistance to intra-abdominal pressure but may produce bowel adhesion and infection. Biological meshes were developed with theaim of avoiding these complications. They are composed of collagen connective tissue derived from decellularized porcine, bovineor human origin. One possibility is to culture current autologous mesenchymal stem cells on biological meshes for the latter to serveas a scaffold for the development of stem cells. Thus, a bioartificial hybrid mesh could be created, composed of a polypropylenemesh and a biological mesh cultured with autologous stem cells. The polypropylene component provides resistance and the biologicalmesh (cultured with stem cells), may provide anti-inflammatory and immunomodulatory properties favoring tissue regeneration,reducing intestinal adhesion, enterocutaneous fistula, and infection. The hypothesis is that a mixed biological component (SIS-cells)reduce the inflammatory reaction and the adhesions to the intestinal tissue generated by polypropylene meshes...

Inhibition of brain ST8SiaIII sialyltransferase leads to impairment of procedural memory in mice.

Several glycoproteins in mammalian brains contain α2,8-linked disialic acid residues. We previously showed a constant expression of disialic acid (DiSia) in the hippocampus, olfactory bulb and cortex, and a gradual decrease of expression in the cerebellum from neonatal to senile mice. Previous publications indicate that neurite extension of neuroblastoma-derived Neuro2A cells is inhibited in the presence of DiSia antibody. Based on this, we treated Neuro2A cell cultures with RNA interference for ST8SiaIII mRNA, the enzyme responsible for DiSia formation. We observed that neurite extension was inhibited by this treatment. Taking this evidence into consideration and the relationship of the cerebellum with learning and memory, we studied the role of DiSia expression in a learning task. Through delivery of pST8SiaIII into the brains of C57BL/6 neonatal mice, we inhibited the expression of ST8SiaIII. ST8SiaIII mRNA and protein expressions were analyzed by real-time PCR and western blot, respectively. In this work, we showed that pST8SiaIII-treated mice presented a significantly reduced level of ST8SiaIII mRNA in the cerebellum (p<0.01) in comparison to control mice at 8 days after treatment. It is also noted that these levels returned to baseline values in the adulthood. Then, we evaluated behavioural performance in the T-Maze, a learning task that estimates procedural memory. At all ages, pST8SiaIII-treated mice showed a lower performance in the test session, being most evident at older ages (p<0.001). Taken all together, we conclude that gene expression of ST8SiaIII is necessary for some cognitive tasks at early postnatal ages, since reduced levels impaired procedural memory in adult mice.

Histologic changes after urethroplasty using small intestinal submucosa unseeded with cells in rabbits with injured urethra.

OBJECTIVE: To determine whether small intestine submucosa has the same regenerative capacity when urethroplasty is performed in injured urethras. METHODS: Our experiment was conducted in 30 New Zealand male rabbits, all of which had urethral injury. One month after the injury, the animals were randomized into a control group or a group with onlay urethroplasty with small intestine submucosa. The animals were euthanized at 2, 4, 12, 24, and 36 weeks after urethroplasty, and their urethras were removed for histologic and immunohistochemical examination. Before the scheduled euthanasia, urethrography and cystoscopy were performed. RESULTS: After 2 weeks, there was evidence of a continuous monolayer of stratified epithelial cells and absence of smooth muscle fibers. One month later, the epithelium showed no changes from the previously observed features, but some smooth muscle fibers (representing newly formed vessels) became apparent. After 3 months, the graft showed increased concentration of smooth muscle fibers. After 6 and 9 months, the density of smooth muscle cells remained unchanged. Fiber arrangement was irregular, particularly at the anastomosis site. Epithelial and smooth muscle phenotypes were confirmed by immunohistochemistry using anti-pan-citokeratin (AE1/AE3) antibodies and anti-α-smooth muscle actin, respectively. CONCLUSION: Small intestine submucosa promotes regeneration in traumatized urethras, with slightly delayed epithelialization and abnormal distribution of smooth muscle. Urethral damage caused by trauma interferes with the normal healing process.

A new model for dura mater healing: human dural fibroblast culture.

OBJECTIVE: Dura mater healing is crucial to prevent cerebrospinal fluid (CSF) leaks after neurosurgical procedures. Biological mechanisms leading to dural closure are only partially understood and have been studied in animals exclusively. We studied an in vitro model of dural closure which uses human cells. MATERIALS AND METHODS: We used human dura intended for disposal after surgery. Explant primary cultures were performed. Cells were characterized through common staining and immunohistochemistry. A cell growth curve was elaborated and the effect of dexamethasone on cell count was assessed. Spongostan®, oxidized regenerated cellulose and autologous plastic materials were also evaluated for their effect on cellular growth. RESULTS: All specimens showed growth in fusiform cells, which project pseudopods and fuse into spindles. Cells showed desmin and vimentin positivity, and were negative for all the other stains, behaving phenotypically like fibroblasts. No collagen base was necessary for cell growth. Dexamethasone decreased cell count in the primary culture as well as in the explant, and reduced the cell proliferation marker Ki-67. Spongostan® was successfully used as a graft, and fibroblast cultures were additionally developed with muscle, pericranium, galea, and fascia. Oxidized cellulose induced cell death by lowering the pH of the solution. DISCUSSION: According to the findings, unlike mini-pigs and rabbits, in humans, dural fibroblast sensitivity to collagen seems to be lower. Dexamethasone inhibits fibroblast invasion, which is the biological base of wound dehiscence in cranial surgery. Although Spongostan is useful, Surgicel® can lower the media pH, thereby inhibiting cellular growth.