Ultrastructural Features of Apoptosis

Apoptosis is a gene-directed physiological and programmed process of cell deletion aimed at the regulation of tissue and organ development. It affects different cell types and is triggered by a variety of stimuli all inducing closely comparable structural changes. Despite the deeply different morphology and metabolism of the cell models and the various inducers and their initial effects, a convergence seems to take place in a common metabolic pathway that, in most cases, involves the activation of a Ca2+ dependent endonuclease. A growing body of data is now available on the molecular events that lead to DNA damage. DNA cleavage in nucleosomic or oligonucleosomic fragments is related to the appearance of unusual and very characteristic ultrastructural changes. The nucleus is especially affected, and shows chromatin rearrangements consisting of cup-shaped marginations, sharply separated from diffuse chromatin areas. Nuclear fragmentation subsequently appears, finally followed by the formation of numerous micronuclei. Cytoplasmic damage appears at a very late stage and the process takes place despite good preservation of plasma membrane and cytoplasm

Melatonin role in skeletal muscle disorders

Abstract. – OBJECTIVE: This review discusses the impact of the neuro-hormone melatonin on skeletal muscle disorders based on recent literature data with the aim to clarify the utility of the melatonin therapy in patients affected by muscle diseases. MATERIALS AND METHODS: It has been pointed out the possible role of melatonin as a food supplement to cure muscular disorders characterized by muscle wasting. Oxidative damage has been proposed as one of the major contributors of the skeletal muscle decline occurring both in physiological and pathological conditions. It is known that excessive oxidant levels lead to mitochondrial damage, and in turn, contribute to apoptotic signaling activation and autophagic impairment. This condition is common in a variety of skeletal muscle disorders. RESULTS: The scientific evidence enhances the antioxidant effect of melatonin, that has been demonstrated by several studies both in vitro and in vivo. This effect counteracts mitochondrial impairments and reduces oxidative stress and autophagic alterations in muscle fibers. Its beneficial role in restoring muscle decline, takes place mainly in atrophic conditions correlated to muscle aging. CONCLUSIONS: The findings of the research suggest that melatonin may be considered as a valid dietary supplement, useful to prevent muscle wasting, in particular, in sarcopenia-associated diseases

Nuclear pores in the apoptotic cell.

During apoptosis, nuclear pores undergo strong modifications, which are described here in five different apoptotic models, Conventional electron microscopy, supported by freeze-fracture analysis, showed a constant migration of nuclear pores towards the diffuse chromatin areas, In contrast, dense chromatin areas appear pore-free and are frequently surrounded by strongly dilated cistemae, A possible functional significance of this pore behaviour during apoptosis is discussed

Alfa-Tocopherol supplementation induces morphological changes in the hippocampus of adult offspring

none6noopenSalucci, Sara; Ambrogini, Patrizia; Lattanzi, Davide; Minelli, Andrea; Falcieri, Elisabetta; Gobbi, PietroSalucci, Sara; Ambrogini, Patrizia; Lattanzi, Davide; Minelli, Andrea; Falcieri, Elisabetta; Gobbi, Pietr

Novel insights into pericarp, protein body globoids of aleurone layer, starchy granules of three cereals gained using atomic force microscopy and environmental scanning electronic microscopy

In this study, we applied Environmental Scanning Electron Microscopy-Energy Dispersive Spectroscopy (ESEM-EDS) and Atomic Force Microscopy (AFM) analysis of three different cereal caryopses: barley, oat and einkorn wheat. The morphological structures, chemical elemental composition and surface characteristics of the three cereals were described. Regarding the morphology, barley showed the thickest pericarp, providing a strong barrier to digestion and absorption of nutrients. The aleurone layer of each cereal type contained protein body globoids within its cells. Large type-A and small type-B starchy granules were revealed in the endosperm of barley and einkorn wheat, whereas irregular starchy granules were found in oats. The starchy granule elemental composition, detected by ESEM-EDS, was rather homogenous in the three cereals, whereas the pericarp and protein body globoids showed heterogeneity. In the protein body globoids, oats showed higher P and K concentrations than barley and einkorn wheat. Regarding the topographic profiles, detected by AFM, einkorn wheat starchy granules showed a surface profile that differed significantly from that of oats and barley, which were quite similar to one another. The present work provides insights into the morphological and chemical makeup of the three grains shedding light on the higher bio-accessibility of einkorn wheat nutrients compared to barley and oats, providing important suggestions for human nutrition and technological standpoints

Dentin proteoglycans: an immunocytochemical FEISEM study.

Dentin proteoglycans are fundamental constituents of the dentin matrix and are distributed ubiquitously both in dentin and cement. They have several important functional properties; in particular, they have a fundamental role in the maintenance and the correct stabilization of collagen fibers. The use of phosphoric acid on dentin, as proposed in most common dental adhesive systems to establish a reliable bond, may affect the molecular structure of proteoglycans. The aim of this study was to evaluate, after the application of EDTA or phosphoric acid on dentin, the dentin proteoglycans with an immunocytochemical approach with high resolution SEM. For this purpose, dentin disks obtained from recently extracted human molars were etched with a 35% water solution of phosphoric acid for 15 s, 30 s, and 60 s. Control specimens were conditioned with EDTA. Specimens were immunolabeled with a monoclonal antibody antichondroitin sulfate and visualized with a gold-conjugated secondary antibody. Conditioning dentin with EDTA resulted in a distinct labeling of the proteoglycans, as visualized on branching fibrillar structures in the order of 10–20 nm. The use of 35% phosphoric acid on dentin revealed a coagulation of proteoglycans after etching for 15 s while a very low labeling signal was detectable after 30 s. No labeling was obtained after etching dentin with phosphoric acid for 60 s. These results suggest that the use of 35% phosphoric acid on dentin is able to produce significant structural modifications of the dentin proteoglycans even after short application times. Additionally, when applied on the dentin surface for more than 30 s, phosphoric acid produces a dramatic decrease in proteoglycans’ antigenicity, probably due to structural modifications of the three-dimensional conformation of these molecules

Evidence for redifferentiation of human chondrocytes grown on a hyaluronan-based biomaterial (HYAFF11): Molecular, Immunohistochemical and ultrastructural analysis.

Association of biomaterials with autologous cells can provide a new generation of implantable devices for cartilage repair. Such scaffolds should provide a preformed three-dimensional shape and prevent cells from escaping into the articular cavity. Furthermore, these constructs should have sufficient mechanical strength to facilitate handling in a clinical setting and stimulate the uniform spreading of cells and their phenotype redifferentiation. The aim of this study was to verify the ability of HYAFF®11, a recently developed hyaluronic-acid-based biodegradable polymer, to support the growth of human chondrocytes and to maintain their original phenotype. This capability was assessed by the evaluation of collagen types I, II and aggrecan mRNA expression. Immunohistochemical analyses were also performed to evaluate collagen types I, II and proteoglycans synthesis. A field emission in lens scanning microscopy was utilized to verify the interactions between the cells and the biomaterial. Our data indicate that human chondrocytes seeded on HYAFF®11 express and produce collagen type II and aggrecan and downregulate the production of collagen type I. These results provide an in vitro demonstration for the therapeutic potential of HYAFF®11 as a delivery vehicle in a tissue-engineered approach towards the repair of articular cartilage defects

Three-Dimensional Virtual Anatomy as a New Approach for Medical Student’s Learning

none8noMost medical and health science schools adopt innovative tools to implement the teaching of anatomy to their undergraduate students. The increase in technological resources for educational purposes allows the use of virtual systems in the field of medicine, which can be considered decisive for improving anatomical knowledge, a requisite for safe and competent medical practice. Among these virtual tools, the Anatomage Table 7.0 represents, to date, a pivotal anatomical device for student education and training medical professionals. This review focuses attention on the potential of the Anatomage Table in the anatomical learning process and clinical practice by discussing these topics based on recent publication findings and describing their trends during the COVID-19 pandemic period. The reports documented a great interest in and a positive impact of the use of this technological table by medical students for teaching gross anatomy. Anatomage allows to describe, with accuracy and at high resolution, organ structure, vascularization, and innervation, as well as enables to familiarize with radiological images of real patients by improving knowledge in the radiological and surgical fields. Furthermore, its use can be considered strategic in a pandemic period, since it ensures, through an online platform, the continuation of anatomical and surgical training on dissecting cadavers.openBartoletti-Stella, Anna; Gatta, Valentina; Mariani, Giulia Adalgisa; Gobbi, Pietro; Falconi, Mirella; Manzoli, Lucia; Faenza, Irene; Salucci, SaraBartoletti-Stella, Anna; Gatta, Valentina; Mariani, Giulia Adalgisa; Gobbi, Pietro; Falconi, Mirella; Manzoli, Lucia; Faenza, Irene; Salucci, Sar

How Inflammation Pathways Contribute to Cell Death in Neuro-Muscular Disorders

Neuro-muscular disorders include a variety of diseases induced by genetic mutations resulting in muscle weakness and waste, swallowing and breathing difficulties. However, muscle alterations and nerve depletions involve specific molecular and cellular mechanisms which lead to the loss of motor-nerve or skeletal-muscle function, often due to an excessive cell death. Morphological and molecular studies demonstrated that a high number of these disorders seem characterized by an upregulated apoptosis which significantly contributes to the pathology. Cell death involvement is the consequence of some cellular processes that occur during diseases, including mitochondrial dysfunction, protein aggregation, free radical generation, excitotoxicity and inflammation. The latter represents an important mediator of disease progression, which, in the central nervous system, is known as neuroinflammation, characterized by reactive microglia and astroglia, as well the infiltration of peripheral monocytes and lymphocytes. Some of the mechanisms underlying inflammation have been linked to reactive oxygen species accumulation, which trigger mitochondrial genomic and respiratory chain instability, autophagy impairment and finally neuron or muscle cell death. This review discusses the main inflammatory pathways contributing to cell death in neuro-muscular disorders by highlighting the main mechanisms, the knowledge of which appears essential in developing therapeutic strategies to prevent the consequent neuron loss and muscle wasting