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Lignocellulosic biomass is an attractive raw material for the production of bioethanol because of its abundance and cheapness, but due to its complex structure the enzymes can penetrate the substrate and obtaining the fermentable sugars from the cellulose is a slow process. As indicated above, lignocellulosic biomass has to pass pretreatments to enhance the enzymatic saccharification. Dilute acid and alkaline H2O2 pretreatments show promises to cheapen the process, making the scaling to industrial stage possible. The optimum conditions for the dilute acid pretreatment were time, 33 min, and acid concentration of 1.56% v/v, obtaining a xylose yield of 89.9% and removing 83.2% of hemicellulose. The alkaline H2O2 pretreatment obtained a glucose concentration of 62.4 g/L with 5% H2O2, liquid:solid ratio 13.47:1 and time 20.7 h. Tween 80 increased the global glucose yield at 87% with 0.3% w/v of Tween and 5-h contact time. The dilute acid pretreatment removed 83% of the hemicellulose in corncob and the alkaline H2O2 pretreatment 56.8% of lignin, obtaining 71% of glucose yield. Finally, Tween 80 increased 19% of global glucose yield. [ABSTRACT FROM AUTHOR]

Background: For medium/small size breast, breast conserving surgery (BCS) is usually associated to poor cosmetic results. The objective of the study is to evaluate oncological safety and cosmetic results comparing the "Crescent" and the "J" mammoplasty technique and to develop an algorithm for the treatment of breast cancer located in lower quadrants in medium/small breast., Methods: We retrospectively analysed all consecutive patients who underwent a "J" mammoplasty or a "Crescent" technique at AUSL IRCCS Reggio Emilia between 2016 and 2021. Fifty-eight patients were enrolled, the first group including 29 "Crescent" technique procedures and the second one including 29 patients who underwent the "J" mammoplasty technique. Oncological safety and surgical minor and major complications were evaluated. Aesthetic results were evaluated by two senior breast surgeons, independently, at least 6 months after radiotherapy (RT)., Results: At follow-up of 36 months, no recurrences and no major complications were observed in both groups. Minor complications were observed in two (6.9%) "J" group cases and in six (20.7%) "Crescent" ones (P<0.05). The 96.6% of "Crescent" and the 73.5% of "J" cases were judged excellent/good. One (3.4%) "Crescent" was judged fair versus six (20.7%) "J" mammoplasty. Two (6.9%) "J" cases were judged poor, requiring ipsilateral re-operation., Conclusions: When a favourable ratio between tumor size and breast volume is present, BCS can be performed for tumors located in the lower quadrants. Evaluating patients' anthropometric characteristics, skin involvement and tumor features is the key to select the right technique and to obtain both great cosmetic result and low rate of complications., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://gs.amegroups.com/article/view/10.21037/gs-24-74/coif). The authors have no conflicts of interest to declare., (2024 Gland Surgery. All rights reserved.)

Background and Aim: The aim of this study was to analyze central line-associated bloodstream infections (CLABSI) in home parenteral nutrition (HPN) patients assisted by an interdisciplinary team during the first year of the COVID-19 pandemic in Argentina., Methods: Longitudinal, retrospective and analytical study of patients on HPN for ≥90 days during 2020. Data collection included age (adults >18 years, pediatric ≤18 years), gender, diagnosis, type of catheter, number of lumens, venous access, days on HPN, infusion modality and number of CLABSI-associated events. In COVID-19 cases, number of patients, disease progression, mortality rate and microorganisms involved were analyzed., Results: A total of 380 patients were included, 120 (31.6%) pediatric and 260 (68.4%) adult patients. Median age was 44.50 years (10; 62.25). Twelve patients (3.15% of the total) had COVID-19; of these, two pediatric and seven adult patients had no complications, and three adults died of COVID-19 pneumonia. The diagnoses observed were benign chronic intestinal failure (CIF, n = 311), grouped into short bowel (n = 214, 56.3%), intestinal dysmotility (n = 56, 14.7%), intestinal fistula (n = 20, 5.3%), and extensive small bowel mucosal disease (n = 21, 5.5%); malignant tumors (n = 52, 13.7%); other (n = 17, 4.4%). Total catheter days were 103,702. Median days of PN duration per patient were 366 (176.2, 366). The types of catheters used were tunneled (317 patients, 83.4%); peripherally inserted central (PICC) line (55 patients, 14.5%) and ports (8 patients; 2.1%). A total of 111 CLABSI was registered, with a prevalence of 1.09/1000 catheter days (adult, 0.86/1000 days; pediatric, 1.51/1000 days). The microorganisms identified in infectious events were Gram + bacteria (38, 34.5%); Gram-bacteria (36, 32%); mycotic (10, 9%); polymicrobial (4, 3.6%); negative culture and signs/symptoms of CLABSI (23, 20.3%). The odds ratio between pediatric and adult patients was 2.29 (1.35, 3.90)., Conclusion: The rate of CLABSI during the COVID-19 pandemic was within the ranges reported by international scientific societies. The risk of CLABSI was higher in pediatric patients, and mortality rate in COVID-19 infected patients was higher than in the general population., Competing Interests: Declaration of competing interest All authors are involved in the follow-up of Nutrihome® patients., (Copyright © 2022 European Society for Clinical Nutrition and Metabolism. Published by Elsevier Ltd. All rights reserved.)

Multirotor drones are becoming increasingly popular in a number of application fields, with a unique appeal to the scientific community and the general public. Applications include security, monitoring and surveillance, environmental mapping, and emergency scenario management: in all these areas, two of the main issues to address are the availability of appropriate software architectures to coordinate teams of drones and solutions to cope with the short-term battery life. This article proposes the novel concepts of Social Drone Sharing (SDS) and Social Charging Station (SCS), which provide the basis to address these problems. Specifically, the article focuses on teams of drones in pre- and post-event monitoring and assessment. Using multirotor drones in these situations can be difficult due to the limited flight autonomy when multiple targets need to be inspected. The idea behind the SDS concept is that citizens can volunteer to recharge a drone or replace its batteries if it lands on their property. The computation of paths to inspect multiple targets will then take into account the availability of SCSs to find solutions compatible with the required inspection and flight times. The main contribution of this article is the development of a cloud-based software architecture for SDS mission management, which includes a multi-drone path-optimization algorithm taking the SDS and SCS concepts into account. Experiments in simulation and a lab environment are discussed, paving the path to a larger trial in a real scenario., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Bisio, Morando, Recchiuto and Sgorbissa.)

Purpose: To assess the association between birth weight and the development of functional gastrointestinal disorders (FGIDs) in the first year of life., Methods: This is a secondary analysis of a prospective cohort multicenter study including neonates, consecutively enrolled at birth, and followed up for one year. At birth all infants were classified by birth weight as extremely low (ELBW), very low, or low when <1,000, <1,500, and <2,500 g, respectively, and by birth weight for gestational age as appropriate (AGA, weight in the 10-90th percentile), small (SGA, weight <10th percentile), and large (LGA, weight >90th percentile) for gestational age. FGIDs were classified according to the Rome III criteria and assessed at 1, 3, 6, and 12 months of life., Results: Among 1,152 newborns enrolled, 934 (81.1%) completed the study: 302 (32.3%) were preterm, 35 (3.7%) were ELBW, 104 (11.1%) were SGA, 782 (83.7%) were AGA, and 48 (5.1%) were LGA infants. Overall, throughout the first year of life, 718 (76.9%) reported at least one FGID. The proportion of infants presenting with at least one FGID was significantly higher in ELBW (97%) compared to LBW (74%) ( p =0.01) and in LGA (85.4%) and SGA (85.6%) compared to AGA (75.2%) ( p =0.0001). On multivariate analysis, SGA was significantly associated with infantile colic., Conclusion: We observed an increased risk of FGIDs in ELBW, SGA, and LGA neonates. Our results suggest that prenatal factors determining birth weight may influence the development of FGIDs in infants. Understanding the role of all potential risk factors may provide new insights and targeted approaches for FGIDs., Competing Interests: Conflicts of Interest: The authors have no financial conflicts of interest., (Copyright © 2020 by The Korean Society of Pediatric Gastroenterology, Hepatology and Nutrition.)

Breast cancer (BC) is the most frequent cancer among women, impacting 2.1 million women each year and having caused 627,000 deaths in 2018. In Italy, BC represents the first cancer diagnosis with 53,000 new cases in 2019 and the first cause of mortality for cancer among the female population. Breast implants represent the first reconstructive choice after mastectomy: in Italy, 411,000 prostheses have been implanted since 2010 and more than 95% of them are macro-texturized. The attempt to reduce complications such as capsular contracture, rotation and rupture of the prosthesis and the most recent BIA-ALCL association with macro-texturized implants have led to the development of new materials and the refinement of implants' coating techniques. We carried out a 1-year prospective single-centre study to evaluate patient-reported quality of life (QoL) and aesthetic outcomes after breast reconstructive surgery using two different prostheses: shaped micro-textured implants and round smooth implants. We treated 62 patients with radical or conservative mastectomy followed by reconstructive surgery performed with 44 shaped implants and 48 round implants. Quality of life evaluated through the Breast-Q ® -questionnaire showed high scores of psycho-social well being in both groups, as well as pre- and post-operative aesthetic satisfaction and physical well being. Round smooth implants appear to be better in terms of softness, volume and less association with rippling, whereas shaped micro-textured implants prove to be better in the profile delineation. This study confirms the potentialities of both shaped micro-textured and round smooth implants in reconstructive surgery.

Background/aim: Despite the large amount of clinical data available of Coronavirus-19 (COVID-19), not many studies have been conducted about the psychological toll on Health Care Workers (HCWs)., Patients and Methods: In this multicentric descriptive study, surveys were distributed among 4 different Breast Cancer Centers (BCC). BCCs were distinguished according to COVID-19 tertiary care hospital (COVID/No-COVID) and district prevalence (DP) (High vs. Low). DASS-21 score, PSS score and demographic data (age, sex, work) were evaluated., Results: A total of 51 HCWs were analyzed in the study. Age, work and sex did not demonstrate statistically significant values. Statistically significant distribution was found between DASS-21-stress score and COVID/No-COVID (p=0.043). No difference was found in the remaining DASS-21 and PSS scores, dividing the HCWs according to COVID-19-hospital and DP., Conclusion: Working in a COVID-19-hospital represents a factor that negatively affects psychosocial well-being. However, DP seems not to affect the psychosocial well-being of BCC HCWs. During the outbreak, psychological support for low risk HCWs should be provided regardless DP., (Copyright© 2020, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Background/aim: In 2016, in the United States, more than 50% of breast cancer (BC) cases were diagnosed in patients older than 60 years of age. Our study aimed to estimate the risk of locoregional recurrence (LR) in patients who underwent breast-conservative treatment (BCT), according to age., Patients and Methods: This retrospective monocentric study analyzed 613 cases of patients who underwent BCT between 2003 and 2014. Patients were divided into groups according to age: Under70 (under 70 years old) and Over70 (above 70 years old). Margins width, histology results, prognostic and predictive factors were compared. Subgroup analysis was performed for patients who experienced LR., Results: LR Incidence among Under70 and Over70 was 5.4% and 1.7%, respectively (p<0.01). Group Over70 is characterized by larger tumors and a lower Ki67 index (p<0.01)., Conclusion: Operation time reduction, better aesthetic results and reduced LR risk support BCT. The Over70 group exhibited better outcomes in terms of LR despite larger tumor dimensions., (Copyright© 2020, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Background/aim: Neoadjuvant chemotherapy (NAC) for breast cancer (BC) is the gold standard treatment for locally advanced tumors (LABC) that aims at achieving a complete pathological response (pCR). Studies have been conducted to evaluate and identify te concordance between radiological, histopathological and biological variables of BC and final response to therapy, verified by definitive histological examination after surgery., Patients and Methods: Ninety-five BC patients were examined and subjected to NAC. Immunohistochemical markers including oestrogen-receptor (ER), progesterone-receptor (PR), Ki67 index, and human epidermal growth factor receptor 2 (HER2) score were examined before and after neoadjuvant treatment., Results: Younger age and a significant decrease in ER expression were associated with better prognosis. Triple Negative (TN) and Her2-type breast cancers benefited most from neoadjuvant chemotherapy with higher frequency of pCR., Conclusion: HER2-type and TN BC are correlated with best response to NAC. A statistically significant correlation between radiological images and definitive histological examination was not observed., (Copyright© 2020, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Objective: To assess the prevalence of functional gastrointestinal disorders (FGIDs) in the first year of life and the influence of different neonatal factors on development of FGIDs., Study Design: A prospective cohort multicenter study including neonates, consecutively enrolled at birth, and followed up until 1 year. Gestational age, neonatal antibiotic administration, duration of hospitalization, mode of delivery, birth weight, and feeding pattern were recorded. FGIDs were classified according to Rome III criteria and assessed at 1, 3, 6, and 12 months of life., Results: Among 1152 newborns enrolled, 934 (81.1%) completed the study, 302 (32%) were newborns born preterm, 320 (34%) had neonatal antibiotics, and 718 (76.9%) had at least 1 FGID according to Rome III criteria (443 [47.4%] infantile colic, 374 [40.0%] regurgitation, 297 [31.8%] infant dyschezia, 248 [26.6%] functional constipation, and 34 [3.6%] functional diarrhea) throughout the first year of life. The proportion of infants born preterm presenting with FGIDs (86%) was significantly greater compared with infants born full term (72.5%) (χ 2  = 21.3, P = .0001). On multivariate analysis, prematurity and neonatal use of antibiotics was significantly associated with at least 1 FGID., Conclusions: We found a high rate FGIDs in infants, likely related to the population recruited, the long observation period, the diagnosis based on Rome III criteria, and parental reports. Preterm delivery and neonatal use of antibiotics in the first months of life are associated with an increased incidence of FGIDs, particularly infantile colic and regurgitation. In our population, cesarean delivery and feeding pattern at 1 month of life emerged as additional risk factors for infant dyschezia and functional diarrhea. Other neonatal factors associated with FGIDs need to be further explored., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The Oxford Classification of IgA Nephropathy (IgAN) identified mesangial hypercellularity (M), endocapillary proliferation (E), segmental glomerulosclerosis (S), and tubular atrophy/interstitial fibrosis (T) as independent predictors of outcome. Whether it applies to individuals excluded from the original study and how therapy influences the predictive value of pathology remain uncertain. The VALIGA study examined 1147 patients from 13 European countries that encompassed the whole spectrum of IgAN. Over a median follow-up of 4.7 years, 86% received renin-angiotensin system blockade and 42% glucocorticoid/immunosuppressive drugs. M, S, and T lesions independently predicted the loss of estimated glomerular filtration rate (eGFR) and a lower renal survival. Their value was also assessed in patients not represented in the Oxford cohort. In individuals with eGFR less than 30 ml/min per 1.73 m(2), the M and T lesions independently predicted a poor survival. In those with proteinuria under 0.5 g/day, both M and E lesions were associated with a rise in proteinuria to 1 or 2 g/day or more. The addition of M, S, and T lesions to clinical variables significantly enhanced the ability to predict progression only in those who did not receive immunosuppression (net reclassification index 11.5%). The VALIGA study provides a validation of the Oxford classification in a large European cohort of IgAN patients across the whole spectrum of the disease. The independent predictive value of pathology MEST score is reduced by glucocorticoid/immunosuppressive therapy.

Understanding the role of lipids in synapses and the aberrant molecular mechanisms causing the cognitive deficits that characterize most lipidosis is necessary to develop therapies for these diseases. Here we describe sphingomyelin (SM) as a key modulator of the dendritic spine actin cytoskeleton. We show that increased SM levels in neurons of acid sphingomyelinase knock out mice (ASMko), which mimic Niemann Pick disease type A (NPA), result in reduced spine number and size and low levels of filamentous actin. Mechanistically, SM accumulation decreases the levels of metabotropic glutamate receptors type I (mGluR1/5) at the synaptic membrane impairing membrane attachment and activity of RhoA and its effectors ROCK and ProfilinIIa. Pharmacological enhancement of the neutral sphingomyelinase rescues the aberrant molecular and morphological phenotypes in vitro and in vivo and improves motor and memory deficits in ASMko mice. Altogether, these data demonstrate the influence of SM and its catabolic enzymes in dendritic spine physiology and contribute to our understanding of the cognitive deficits of NPA patients, opening new perspectives for therapeutic interventions.

Neuronal plasticity is an important process for learning, memory and complex behaviour. Rapid remodelling of the actin cytoskeleton in the postsynaptic compartment is thought to have an important function for synaptic plasticity. However, the actin-binding proteins involved and the molecular mechanisms that in vivo link actin dynamics to postsynaptic physiology are not well understood. Here, we show that the actin filament depolymerizing protein n-cofilin is controlling dendritic spine morphology and postsynaptic parameters such as late long-term potentiation and long-term depression. Loss of n-cofilin-mediated synaptic actin dynamics in the forebrain specifically leads to impairment of all types of associative learning, whereas exploratory learning is not affected. We provide evidence for a novel function of n-cofilin function in synaptic plasticity and in the control of extrasynaptic excitatory AMPA receptors diffusion. These results suggest a critical function of actin dynamics in associative learning and postsynaptic receptor availability.

Background: Rett syndrome (RTT) is an X-linked progressive neurodevelopmental disorder characterized by a variety of symptoms including motor abnormalities, mental retardation, anxiety, and autism. Most of RTT cases are caused by mutations of MeCP2. In mice, impaired MeCP2 function results in synaptic deficits associated with motor, cognitive, and emotional alterations. Environmental enrichment (EE) is a rearing condition that enhances synapse formation and plasticity. Previous studies analyzing the effects of postweaning EE found limited effects on motor performance of male MeCP2 mutants. However, EE during early postnatal development produces powerful effects on neural development and plasticity. Thus, we tested whether early EE could ameliorate several phenotypes of male homozygous and female heterozygous MeCP2 mutants., Methods: We investigated the effects of early EE on motor coordination, structural and functional synaptic plasticity, and brain-derived neurotrophic factor expression in male MeCP2 null mice. Anxiety-related behavior and spatial learning was analyzed in heterozygous MeCP2 female mice., Results: In male mutants, EE modified excitatory and to a lesser extent inhibitory synaptic density in cerebellum and cortex, reversed the cortical long-term potentiation deficit and augmented cortical brain-derived neurotrophic factor levels. Environmental enrichment also ameliorated motor coordination and motor learning. In female heterozygous mice, a model closely mimicking some aspects of RTT symptoms, EE rescued memory deficits in the Morris water maze and decreased anxiety-related behavior., Conclusions: Early EE dramatically improves several phenotypes of MeCP2 mutants. Thus, environmental factors should be taken into account when analyzing phenotypes of MeCP2 knockout mice, an accepted model of RTT. Early EE might be beneficial in RTT patients., (Copyright 2010 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.)

Administration of mesenchymal stem cells (MSCs) improves the recovery from acute kidney injury (AKI). The mechanism may involve paracrine factors promoting proliferation of surviving intrinsic epithelial cells, but these factors remain unknown. In the current study, we found that microvesicles derived from human bone marrow MSCs stimulated proliferation in vitro and conferred resistance of tubular epithelial cells to apoptosis. The biologic action of microvesicles required their CD44- and beta1-integrin-dependent incorporation into tubular cells. In vivo, microvesicles accelerated the morphologic and functional recovery of glycerol-induced AKI in SCID mice by inducing proliferation of tubular cells. The effect of microvesicles on the recovery of AKI was similar to the effect of human MSCs. RNase abolished the aforementioned effects of microvesicles in vitro and in vivo, suggesting RNA-dependent biologic effects. Microarray analysis and quantitative real time PCR of microvesicle-RNA extracts indicate that microvesicles shuttle a specific subset of cellular mRNA, such as mRNAs associated with the mesenchymal phenotype and with control of transcription, proliferation, and immunoregulation. These results suggest that microvesicles derived from MSCs may activate a proliferative program in surviving tubular cells after injury via a horizontal transfer of mRNA.

Consensus exists that lipids must play key functions in synaptic activity but precise mechanistic information is limited. Acid sphingomyelinase knockout mice (ASMko) are a suitable model to address the role of sphingolipids in synaptic regulation as they recapitulate a mental retardation syndrome, Niemann Pick disease type A (NPA), and their neurons have altered levels of sphingomyelin (SM) and its derivatives. Electrophysiological recordings showed that ASMko hippocampi have increased paired-pulse facilitation and post-tetanic potentiation. Consistently, electron microscopy revealed reduced number of docked vesicles. Biochemical analysis of ASMko synaptic membranes unveiled higher amounts of SM and sphingosine (Se) and enhanced interaction of the docking molecules Munc18 and syntaxin1. In vitro reconstitution assays demonstrated that Se changes syntaxin1 conformation enhancing its interaction with Munc18. Moreover, Se reduces vesicle docking in primary neurons and increases paired-pulse facilitation when added to wt hippocampal slices. These data provide with a novel mechanism for synaptic vesicle control by sphingolipids and could explain cognitive deficits of NPA patients.

Competition among different axons to reach the somatodendritic region of the target neuron is an important event during development to achieve the final architecture typical of the mature brain. Trasmitter-receptor matching is a critical step for the signaling between neurons. In the cerebellar cortex, there is a persistent competition between the two glutamatergic inputs, the parallel fibers and the climbing fibers, for the innervation of the Purkinje cells. The activity of the latter input is necessary to maintain its own synaptic contacts on the proximal dendritic domain and to confine the parallel fibers in the distal one. Here, we show that climbing fiber activity also limits the distribution of the GABAergic input in the proximal domain. In addition, blocking the activity by tetrodotoxin infusion in Wistar rat cerebellum, a synapse made by GABAergic terminals onto the recently formed Purkinje cell spines appear in the proximal dendrites. The density of GABAergic terminals is increased, and unexpected double symmetric/asymmetric postsynaptic densities add to the typical symmetric phenotype of the GABAergic shaft synapses. Moreover, glutamate receptors appear in these ectopic synapses even in the absence of glutamate transmitter inside the presynaptic terminal and close to GABA receptors. These results suggest that the Purkinje cell has an intrinsic tendency to develop postsynaptic assemblies of excitatory types, including glutamate receptors, over the entire dendritic territory. GABA receptors are induced in these assemblies when contacted by GABAergic terminals, thus leading to the formation of hybrid synapses.

Selected probiotics (mainly Lactobacilli, and particularly LGG, and Saccharomyces boulardii) have recently demonstrated a therapeutic efficacy in acute diarrhoea, if used in the early phase of infection and at high concentration. Further data are needed to clarify their effect for prevention and travellers' diarrhoea. The mechanisms of action of probiotics need to be fully elucidated but seem to include a complex interaction of epithelial, molecular, metabolic and immune responses. There is an increasing evidence that different micro-organisms show different properties and efficacy. An accurate identification and selection of the strains, the dose and the patients are thus crucial for a correct therapeutic approach. Prebiotics can modify the intestinal flora and interact with the immune system of the host against specific pathogens. However, clinical trials are currently limited and a beneficial effect of prebiotics in acute diarrhoea is still lacking. In developing countries zinc supplementation demonstrated a significant reduction of fecal excretion, duration, severity and persistency of diarrhoea. Moreover, zinc may improve immune status, intestinal permeability, epithelial and enzymatic functions, and transport of electrolytes. The use of zinc in addition to oral rehydration solution (ORS) could thus theoretically improve the treatment and reduce the complications of diarrhoea worldwide. However, in developed countries, no trial using zinc supplementation in patients with acute diarrhoea has been published yet and the cost-benefit ratio of zinc supplementation needs to be assessed.

Spines can grow and retract within hours of activity perturbation. We investigated the time course of spine formation in a model of plasticity involving changes in brain architecture where spines of a dendritic domain become innervated by a different neuronal population. Following a lesion of rat olivocerebellar axons, by severing the inferior cerebellar peduncle, new spines grow on the deafferented proximal dendrite of the Purkinje cells (PCs) and these new spines become innervated by parallel fibres (PFs) that normally contact only the distal dendrites. The varicosities of climbing fibre (CF) terminal arbors disappear within 3 days of the lesion. Spine density in the proximal dendritic domain begins to rise within 3 days and continues to increase towards a plateau at 6-8 days. In 'slow Wallerian degeneration' mice, in which axonal degeneration is delayed, climbing fibre varicosities virtually disappear at 14 rather than 3 days. Spine density in the proximal dendritic domain is similar to control Purkinje cells up to 14 days and increases significantly 18 days postlesion. The delayed spinogenesis in the latter mutant is the result of a persistence of the climbing fibre presynaptic structure in the absence of activity. Therefore, climbing fibre activity itself is not directly responsible for the suppression of spine formation, but suppression mechanisms tend to become weaker as long as the structural dismantling of the presynaptic varicosities proceeds. Thus, spinogenesis is guided by two different mechanisms; a rapid one related to changes in homotypic remodeling and a slower one, which requires the removal of a competitive afferent.

The Purkinje cell of the cerebellar cortex presents two distinct dendritic domains: a distal one, with spiny branchlets and a high density of spines innervated by many parallel fibers, and a proximal one, with a few clusters of spines innervated by a single climbing fiber terminal arbor. In adult rats, after 7 days of blocked electrical activity by the administration of TTX into the cerebellar parenchyma, the proximal dendritic domain of the Purkinje cell shows a remarkable growth of new spines that are innervated by parallel fibers. At the same time, the climbing fiber terminal arbor tends to become atrophic. In contrast, in the branchlets, spine density remains unmodified. These changes are reversible when TTX is removed. TTX treatment also leads to a decrease in spine size both in the branchlets and in the new spines of the proximal dendritic compartment. Spontaneous electrical activity should therefore be regarded not simply as noise, but as a significant signal for maintaining the typical profile of afferent innervation of the Purkinje cell and for preventing spines from shrinking.

Previous experiments have shown that in the mature cerebellum both blocking of spontaneous electrical activity and destruction of the climbing fibres by a lesion of the inferior olive have a similar profound effect on the spine distribution on the proximal dendrites of the Purkinje cells. Many new spines develop that are largely innervated by parallel fibers. Here we show that blocking electrical activity leads to a significant decrease in size of the spines on the branchlets. We have also compared the size of the spines of the proximal dendritic domain that appear during activity block and after an inferior olive lesion. In this region also, the spines in the absence of activity are significantly smaller. In the proximal dendritic domain, the new spines that develop in the absence of activity are innervated by parallel fibers and are not significantly different in size from those of the branchlets, although they are shorter. Thus, the spontaneous activity of the cerebellar cortex is necessary not only to maintain the physiological spine distribution profile in the Purkinje cell dendritic tree, but also acts as a signal that prevents spines from shrinking.

Background/aims: Previous experiments have shown that agmatine, the product of arginine decarboxylase, is transported in competition with putrescine into quiescent rat hepatocytes, where it promotes several effects, including marked decrease of intracellular polyamines and induction of apoptosis. The primary aim of the present study was to assess the action of agmatine on transformed and proliferating hepatic rat cells., Methods: To assess the effect of agmatine on hepatoma cells, analysis by flow cytometry, Western blotting, reverse transcription-polymerase chain reaction, scanning and transmission electron microscopy, immunofluorescence detection of beta-actin and alpha-tubulin were performed., Results: The results showed that agmatine has antiproliferative effects on the cell lines studied (HTC, JM2, HepG2). Further experiments were performed on HTC cells. The effect was proportional to agmatine concentration (in a range between 50 and 500 microM). It was not correlated with induction of necrosis or apoptosis and was accompanied by accumulation in G(2)/M cell cycle phase and by dramatic modification of cell morphology. Spermidine reversed these effects, suggesting that the marked decrease of the polyamine pool is the main target of agmatine ., Conclusions: The results obtained show a relationship between the decrease of intracellular polyamine content, the rate of cell growth and the cytoskeleton organization.