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Discusses hypersensitivity to cows' milk allergens. Food allergy in childhood; Diagnostic tests; Dietary management.

In the Medicago genus, saponins are complex mixtures of triterpene pentacyclic glycosides extensively studied for their different and economically relevant biological and pharmaceutical properties. This research is aimed at determining for the first time the tissue and cellular localization of triterpene saponins in vegetative organs of Medicago truncatula, a model plant species for legumes, by histochemistry and transmission electron microscopy. The results showed that saponins are present mainly in the palisade mesophyll layer of leaves, whereas in stems they are mostly located in the primary phloem and the subepidermal cells of cortical parenchyma. In root tissue, saponins occur in the secondary phloem region. Transmission electron microscopy revealed prominent saponin accumulation within the leaf and stem chloroplasts, while in the roots the saponins are found in the vesicular structures. Our results demonstrate the feasibility of using histochemistry and transmission electron microscopy to localize M. truncatula saponins at tissue and cellular levels and provide important information for further studies on biosynthesis and regulation of valuable bioactive saponins on agronomic relevant Medicago spp., such as alfalfa (Medicago sativa L.). RESEARCH HIGHLIGHTS: The Medicago genus represents a valuable rich source of saponins, one of the most interesting groups of secondary plant metabolites, which possess relevant biological and pharmacological properties. Plant tissue and cellular localization of saponins is of great importance to better understand their biological functions, biosynthetic pathway, and regulatory mechanisms. We elucidate the localization of saponins in Medicago truncatula with histochemical and transmission electron microscopy studies., (© 2024 Wiley Periodicals LLC.)

Cells are continuously exposed to various sources of insults, among which temperature variations are extremely common. Epigenetic mechanisms, critical players in gene expression regulation, undergo alterations due to these stressors, potentially leading to health issues. Despite the significance of DNA methylation and histone modifications in gene expression regulation, their changes following heat and cold shock in human cells remain poorly understood. In this study, we investigated the epigenetic profiles of human cells subjected to hyperthermia and hypothermia, revealing significant variations. Heat shock primarily led to DNA methylation increments and epigenetic modifications associated with gene expression silencing. In contrast, cold shock presented a complex scenario, with both methylation and demethylation levels increasing, indicating different epigenetic responses to the opposite thermal stresses. These temperature-induced alterations in the epigenome, particularly their impact on chromatin structural organization, represent an understudied area that could offer important insights into genome function and potential prospects for therapeutic targets., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier GmbH.. All rights reserved.)

Potassium permanganate solution has been used both as a fixative and as a staining for ultrathin sections at transmission electron microscopy, due to its ability to provide good contrast of different tissue components. Subsequently, it has been forgotten due to disadvantages such as conspicuous formation of precipitates and fragility of the tissue sections treated with this dye when placed under the electron beam. Here we demonstrate that the observed granularity of the sections is not related to the formation of non-specific precipitates, but rather to basic proteins such as chromatin proteins closely associated with DNA and ribosomal particles which are intensely stained. This results in a marked contrast of the nuclei, in particular of the heterochromatin areas, the granular component of the nucleoli, and the rough endoplasmic reticulum, that are rich in these protein complexes. We also show how the embedding in LR white acrylic resin can preserve a good morphology and be less sensitive to the treatment with potassium permanganate than the epoxy resin sections, also allowing to perform immunocytochemistry. The fragility of the epoxy resin sections can be partially improved by using formvar-coated grids., (© 2023. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Mercury is a highly toxic element that induces severe alterations and a broad range of adverse effects on health. Its exposure is a global concern because it is widespread in the environment due to its multiple industrial, domestic, agricultural and medical usages. Among its various chemical forms, both humans and animals are mainly exposed to mercury chloride (HgCl 2 ), methylmercury and elemental mercury. HgCl 2 is metabolized primarily in the liver. We analysed the effects on the nuclear architecture of an increasing dosage of HgCl 2 in mouse hepatocytes cell culture and in mouse liver, focusing specifically on the organization, on some epigenetic features of the heterochromatin domains and on the nucleolar morphology and activity. Through the combination of molecular and imaging approaches both at optical and electron microscopy, we show that mercury chloride induces modifications of the heterochromatin domains and a decrease of some histones post-translational modifications associated to heterochromatin. This is accompanied by an increase in nucleolar activity which is reflected by bigger nucleoli. We hypothesized that heterochromatin decondensation and nucleolar activation following mercury chloride exposure could be functional to express proteins necessary to counteract the harmful stimulus and reach a new equilibrium., (© 2022. The Author(s).)

Terbium citrate staining represents the method of choice for RNA visualization at transmission electron microscopy. Because of its affinity for guanosines in RNA rather than in DNA, terbium citrate gives precise results being a selective staining. However, difficulties often arise when performing this technique, especially in crucial and delicate steps such as rinses, when it is not uncommon to excessively reduce the already feeble contrast. For these reasons, we developed a straightforward and secure approach to overcome such complications. Here we report a new method for RNA single molecule localization by means of terbium citrate vapors, viable for every type of fixation and embedding., (© 2023. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Re-establishment of desiccation tolerance is essential for the survival of germinated seeds facing water deficit in the soil. The molecular and ultrastructural features of desiccation tolerance maintenance and loss within the nuclear compartment are not fully resolved. In the present study, the impact of desiccation-induced genotoxic stress on nucleolar ultrastructure and ribogenesis was explored along the rehydration-dehydration cycle applied in standard seed vigorization protocols. Primed and overprimed Medicago truncatula seeds, obtained through hydropriming followed by desiccation (dry-back), were analysed. In contrast to desiccation-tolerant primed seeds, overprimed seeds enter irreversible germination and do not survive dry-back. Reactive oxygen species, DNA damage and expression profiles of antioxidant/DNA Damage Response genes were measured, as main hallmarks of the seed response to desiccation stress. Nuclear ultrastructural features were also investigated. Overprimed seeds subjected to dry-back revealed altered rRNA accumulation profiles and up-regulation of genes involved in ribogenesis control. The signal molecule PAP (3'-phosphoadenosine 5'-phosphate) accumulated during dry-back only in primed seeds, as a distinctive feature of desiccation tolerance. The presented results show the molecular and ultrastructural landscapes of the seed desiccation response, including substantial changes in nuclear organization., (© 2022 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.)

Conservation of plant genetic diversity is fundamental for crop improvement, increasing agricultural production and sustainability, especially in the face of climatic changes. Although seed longevity is essential for the management of seed banks, few studies have, so far, addressed differences in this trait among the accessions of a single species. Eight Pisum sativum L. (pea) accessions were investigated to study the impact of long-term (approximately 20 years) storage, aiming to reveal contrasting seed longevity and clarify the causes for these differences. The outstanding seed longevity observed in the G4 accession provided a unique experimental system. To characterize the biochemical and physical status of stored seeds, reactive oxygen species, lipid peroxidation, tocopherols, free proline and reducing sugars were measured. Thermoanalytical measurements (thermogravimetry and differential scanning calorimetry) and transmission electron microscopy combined with immunohistochemical analysis were performed. The long-lived G4 seeds neither consumed tocopherols during storage nor showed free proline accumulation, as a deterioration hallmark, whereas reducing sugars were not affected. Thermal decomposition suggested a biomass composition compatible with the presence of low molecular weight molecules. Expansion of heterochromatic areas and reduced occurrence of γH2AX foci were highlighted in the nucleus of G4 seeds. The longevity of G4 seeds correlates with the occurrence of a reducing cellular environment and a nuclear ultrastructure favourable to genome stability. This work brings novelty to the study of within-species variations in seed longevity, underlining the relevance of multidisciplinary approaches in seed longevity research., (© 2022 The Authors. Physiologia Plantarum published by John Wiley & Sons Ltd on behalf of Scandinavian Plant Physiology Society.)

Since the discovery of DNA structure in 1953, the deoxyribonucleic acid has always been playing a central role in biological research. As physical and ordered nucleotides sequence, it stands at the base of genes existence. Furthermore, beside this 2-dimensional sequence, DNA is characterized by a 3D structural and functional organization, which is of interest for the scientific community due to multiple levels of expression regulation, of interaction with other biomolecules, and much more. Analogously, the nucleic acid counterpart of DNA, RNA, represents a central issue in research, because of its fundamental role in gene expression and regulation, and for the DNA-RNA interplay. Because of their importance, DNA and RNA have always been mentioned and studied in several publications, and the European Journal of Histochemistry is no exception. Here, we review and discuss the papers published in the last 60 years of this Journal, focusing on its contribution in deepening the knowledge about this topic and analysing papers that reflect the interest this Journal always granted to the world of DNA and RNA.

The spread technique proposed by Miller and Beatty in 1969 allowed for the first time the visualization at transmission electron microscopy of nucleic acids and chromatin in an isolated and distended conformation. The final step of staining the spread chromatin is of critical importance because it can strongly influence the interpretation of the results. We evaluated different staining techniques and the most part of them provided a good result. Specifically, well contrasted micrographs were obtained when staining with H3PW12O40 (PTA), as originally proposed by Miller and Beatty, and with two alternatives proposed here: uranyl acetate or terbium citrate staining. Quite good contrast of the spread DNA could be achieved also by using Osmium Ammine; while no or few contrast of nucleic acids was observed by staining with KMnO₄ and H3PMo12O40 (PMA) respectively.

In the last decades, it has become increasingly clear how the modulation of spatial organization of chromatin over time and through the cell cycle is closely connected to gene function regulation. Different physicochemical stimuli contribute to the realization of specific transcriptional programs and finally to a specific cellular phenotype. In this review, we aim to describe the current knowledge about the dynamics regulating the movements and the interactions of molecules within the nucleus and their impact on gene functions. In particular, taking into account that these forces exert their effect in a nuclear environment characterized by a high concentration of molecules, we will discuss the role of proteins and structures that regulate these movements and transduce physicochemical signals acting on the cell to the nucleus., (© The Author(s) 2020. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.)

Increasing evidence demonstrates that RNA nucleotides undergo epigenetic modifications, such as methylation on cytosine. Although the presence of modified bases on mRNA has been proven, their molecular significance is largely undefined. We describe here a methodology to dissect the timing of modification of cytosine to 5-methylcytosine (5mC or m 5 C) in relation to RNA elongation and processing. To do this we use chlorouridine and iodouridine, two synthetically modified nucleotide bases which can be recognized by RNA polymerase II and incorporated into nascent RNA. These modified bases are added to a cell culture for defined intervals of time, and then immunocytochemical staining using antibodies against the modified nucleotides is carried out. This procedure allows us to identify the range of time in which 5mC is produced in nascent mRNA. This method provides the ultra-resolution of electron microscopy and allows following nascent RNA molecules during their elongation.

Acute toxic exposures in childhood are quite a frequent event in Paediatric Emergency Medicine. Despite that, there are few papers about clinical toxicology in children, at least in Italy. This paper is the first that takes into account both epidemiological aspects and clinical features of acute poisoning in children on a national basis. Collected data show the increased use of activated charcoal as a treatment and the use of the short stay observation unit as an appropriate answer to the real clinical situation, although some aspects are still controversial. It will be necessary to reconsider the whole matter widening the number of participating centres, so that the most controversial aspects may be clarified.

The incidence of coeliac disease (CD) was calculated on 304 patients under eighteen who were born in the city of Turin and its province in the years 1975-1989; the prevalence on 494 patients who live in the Piedmont Region. The mean crude yearly incidence was 0.511/1000 (1:1957 live birth). It varied from year to year, reaching minimum values in the years 1984-1987. In a contemporary epidemiological study, the mean crude incidence of CD in Italy was 1.2/1000 (1:833 live birth) twice the rate observed in Turin. The prevalence of paediatric CD in Piedmont was 113 per million inhabitants. Since CD has a normal life expectancy, its prevalence may be expected to increase. In the provinces of Novara, Alessandria and Asti CD prevalence was lower than in the others. Mean age at onset was 6 mos in 1975 and increased to 34 mos in 1989. Mean age at diagnosis was 15 mos in 1981, and 7 yrs in 1989. Symptoms were more numerous and severe in patients under 12 mos of age, and became fewer and often atypical in older children. We can therefore speculate that the trend towards a decreasing incidence of CD in recent years my be due to delayed diagnosis.

Psittacosis or ornithosis is a bird disease caused by Chlamydia psittaci which can be transmitted to man. Little is known of the epidemiology of the disease in this region, but occasional cases which have been brought to the authors' attention have prompted an epidemiological study on the subject. The preliminary results indicate a surprising percentage, over 8%, of antibodies in infants and children. This percentage varies little in relation to place of residence, rural or urban, or the presence of animals, but confirms the high risk in parrot-owning households where anti-Chlamydia antibodies are found in 37.5% of children.

The evaluation of serum ferritin level in a population of 30 three months old babies is made by the Authors following a radioimmunological method. The reckoned average values reflect exactly the wellknown elements of iron kinetics during the first months of life. The Authors underline that those values show how complete is breast-feeding; moreover they emphasize the importance of a referring value which, together with those already known in subjects of different ages, allows on early diagnosis of syndromes due to iron decrease and subsequent check-up after therapeutic trial.

The literature and personal experience are referred to in an assessment of psycho-affective situations in hospitalised children awaiting non-emergency surgery (appendicectomy, adenotonsillectomy, inguinal hernia, phymosis, hypospadias, cryptorchidism). Psychological and somatic damage resulting from an absence of preparation before hospitalisation and during admission immediately prior to surgery is described. A method whereby this may be avoided as far as possible with the aid of relatives is described.