Search Results (159)

Syphilis, which is caused by Treponema pallidum, remains one of the most common congenital infection worldwide and has tremendous consequences for the mother and her developing foetus if left untreated. The complexity of the exposure to this pathogen extends beyond the well-established clinical manifestations, as it can profoundly affect placental histomorphology. This study aimed to compare T. pallidum-exposed placental villi structures with healthy placentae at term to evaluate the histomorphological differences using stereology. In this case-control study conducted at term (38 weeks ± 2 weeks), 78 placentae were collected from the hospital delivery suites, comprising 39 cases (T. pallidum-exposed) and 39 controls (non-exposed), who were gestational age-matched with other potential confounders excluded. Blood samples from the umbilical vein and placental basal plate were tested for syphilis, using rapid diagnostic test (RDT) kits for T. pallidum (TP) antibodies (IgG and IgM) to classify placentae as exposed to T. pallidum (cases) and non-exposed (controls). Tissue sections were prepared and stained with haematoxylin and eosin, and the mean volume densities of syncytial knots, foetal capillaries, syncytial denuded areas, and intervillous spaces were estimated using stereological methods. Statistical analysis was performed to compare the mean values between the case and control groups. Stereological assessment revealed significant differences between the T. pallidum-exposed and non-exposed groups with regard to syncytial knots (p < 0.0001), syncytial denudation (p < 0.0001), and foetal capillaries (p < 0.0001), but no significant difference in the intervillous space was found (p = 0.1592). Therefore, our study shows, for the first time, that the histomorphology of human placental villi appears to be altered by exposure to T. pallidum. It will, therefore, be interesting to determine whether these changes in the placental villi translate into long-term effects on the baby. Full article

Global warming raises surface water temperatures, impacting fish alongside pollutants, such as ubiquitous xenoestrogens. Combined stressor effects are poorly studied but likely to worsen impacts and hinder biota adaptation, warranting further research. Unadapted fish face heightened risks. The liver is a vital metabolic organ, sensitive to temperature and xenoestrogens, eventually adjusting hepatocyte size and number to ensure survival, growth, and reproduction. This study assessed, for the first time, the impact of exposure (45 days) to thermal stress (29 °C versus 26 °C) and ethinylestradiol (EE2, 5 ng/L) on male guppies, primarily on body and quantitative liver morphology. Higher temperature reduced body mass (14%) and standard length (3.6%) gain. EE2 exposure reduced body mass increase (14%), hepatosomatic index (20%), and the volumes of the liver (32%), hepatocytes (16%), and their nuclei (17%). The nucleus-to-cytoplasm ratio and total hepatocyte number remained stable. No histopathological lesions existed. Guppies appear to have adapted to stressors by reducing hepatocyte size and utilizing lipid reserves, yet they exhibited deficits in body growth and hepatosomatic index. Gonadal maturation was unaffected. Only under EE2 at 29 °C did hepatocytes show minimal lipid droplet content (less vacuolation). This indicated exhausted reserves, reinforcing how heat and toxicants interact to exacerbate impacts. Full article

Background: Salmonella infections impose a substantial global health burden, with an estimated 95.1 million cases occurring annually. Pregnant women exhibit a heightened vulnerability due to pregnancy-specific immune adaptations and dietary habits that increase their risk of Salmonella exposure, facilitating possible damage to the placental barrier. Despite this significant burden, Salmonella-associated placental pathology remains poorly understood, particularly its impact on foetal development through microstructural alterations. Aim: This study utilised stereology to assess histomorphological and functional alterations in term placentae of Salmonella Typhi-exposed placentae, compared to unexposed controls. Methods: A hospital-based case-control study was conducted in Ghana. Of 237 screened women, 62 placentae were selected for analysis, comprising 31 Salmonella-exposed cases (IgG/IgM-positive in placental and cord blood) and 31 gestational age-matched controls (IgG/IgM-negative). Placental tissues were processed for histology and stereology. Neonatal birthweights were also compared. Results: Stereological assessment revealed significantly higher mean volume densities of syncytial knots in the study group (0.4755 ± 0.04) compared to the controls (0.3342 ± 0.04, p = 0.0219). Syncytial denudation was increased in the study group (0.8113 ± 0.09) relative to the controls (0.1975 ± 0.08, p < 0.0001). Foetal capillary volume density was also significantly elevated in the study group (5.1010 ± 0.32) compared to the controls (3.562 ± 0.47, p < 0.0001). In contrast, intervillous space volume was significantly reduced in the study group (9.5810 ± 0.05) compared to the controls (11.593 ± 0.26, p = 0.0053). Neonates of exposed mothers showed a non-significant reduction in birthweight. Conclusion: Salmonella Typhi exposure in pregnancy induces subtle, yet significant alterations in placental architecture, compromising villous integrity and vascular organisation. Although birthweight may appear unaffected, the observed changes point to reduced placental efficiency and merit further research into their developmental consequences and long-term effects on babies. Full article

The study investigates the influence of an air-entraining admixture on the properties and pore structure of ordinary concrete. The aim was to examine how modifications to the concrete mix affect compressive strength, ultrasonic pulse velocity, and resistance to freeze–thaw cycles. Concrete samples with varying admixture dosages (0.00–1.50% of cement mass) were tested for mechanical properties and pore structure. Freeze–thaw resistance was assessed using both direct (PN-B-06265) and indirect methods (EN 480-11), while pore characteristics were evaluated via computer-aided image analysis. Results show that increasing the admixture dosage enhances freeze–thaw resistance by refining the pore structure—particularly by increasing the content of micropores below 0.3 mm—while simultaneously reducing compressive strength and ultrasonic velocity. Statistical analysis revealed that pore parameters such as total air content, specific surface area, and spacing factor significantly correlate with concrete performance. The regression models confirmed that compressive strength and ultrasonic velocity are negatively impacted by increased pore volume, while freeze–thaw resistance improves due to a more favorable pore size distribution. The findings demonstrate that optimizing the admixture dosage can effectively balance durability and mechanical performance, and that quantitative stereological parameters provide a valuable basis for predicting the behavior of air-entrained concrete. Full article

The lemon flavonoid extract Eriomin^® (LE), which is rich in eriocitrin, has demonstrated antioxidant and anti-inflammatory properties in both animal and human studies. Given the established interplay among aging, oxidative stress, and inflammation, this study investigated the influences of LE on the pituitary–adrenal (PA) axis in aged rats and its potential to mitigate age-related physiological changes in this system. The effects of LE (40 mg/kg/day suspended in sunflower oil) on the morphofunctional properties of the PA axis were studied in 24-month-old male Wistar rats following four weeks of oral treatment. Control groups included vehicle-treated (sunflower oil; CON) and untreated intact controls (ICON). Stereological and imaging analyses revealed no significant changes in pituitary ACTH cells; however, Pomc gene expression was significantly downregulated in the LE group compared to both controls (p ≤ 0.05). LE treatment resulted in a significant reduction in adrenal gland weight (p ≤ 0.05), adrenal gland volume (p ≤ 0.01), zona fasciculata (ZF) volume (p ≤ 0.01) and ZF cell volume (p ≤ 0.05). These changes were accompanied by a significant decrease in serum corticosterone levels (p ≤ 0.05). In conclusion, LE downregulated PA axis activity in aged rats. Considering the association between age-related increases in PA activity and adverse health outcomes, citrus flavonoid extracts such as LE may hold promise as anti-aging supplements aimed at mitigating age-related stress dysregulation. Full article

Machine learning strategies for the semantic segmentation of materials’ micrographs, such as U-Net, have been employed in recent years to enable the automated identification of grain-boundary networks in polycrystals. For example, most recently, this architecture has allowed researchers to address the long-standing problem of automated image segmentation of thin-film microstructures in bright-field TEM micrographs. Such approaches are typically based on the minimization of a binary cross-entropy loss function that compares constructed images to a ground truth at the pixel level over many epochs. In this work, we quantify the rate at which the underlying microstructural features embodied in the grain-boundary network, as described stereologically, are also learned in this process. In particular, we assess the rate of microstructural learning in terms of the moments of the k-th nearest-neighbor pixel distributions and associated metrics, including a microstructural cross-entropy, that embody the spatial correlations among the pixels through a hierarchy of n-point correlation functions. From the moments of these distributions, we obtain so-called learning functions that highlight the rate at which the important topological features of a grain-boundary network appear. It is found that the salient features of network structure emerge after relatively few epochs, suggesting that grain size, network topology, etc., are learned early (as measured in epochs) during the segmentation process. Full article

Background: Early-life stress and dietary habits are key determinants of metabolic health. This study investigates the combined effects of maternal separation (MS) and a post-weaning high-fat diet (HFD) on liver morphology in male C57BL/6 mice. Methods: Male mice were subjected to MS during early postnatal life or kept unmanipulated (UM). After weaning, animals were assigned to either a control diet (CD) or an HFD, forming four groups: UM-CD, UM-HFD, MS-CD, and MS-HFD. Liver histology, collagen deposition, and both morphometric and stereological parameters were assessed following 16 weeks of dietary intervention. Results: MS and HFD independently altered liver structure, while the combination of both factors intensified these changes. The MS-HFD group exhibited pronounced steatosis, mixed inflammatory infiltrates, and hepatocellular ballooning, with a significantly higher NAFLD Activity Score (NAS). No significant differences were observed in liver fibrosis. Morphometric analysis revealed increased body mass in HFD-fed groups and elevated liver mass in MS-HFD. Liver volume was higher in MS-HFD, though not significantly. Liver stereology revealed reduced numerical density of hepatocytes (Nv_hep) and increased surface density (Sv_hep) in MS groups, with the most pronounced effects in MS-HFD. Conclusions: Maternal separation amplifies the hepatic alterations induced by HFD, promoting early inflammatory and steatotic changes. These findings highlight the significance of early-life stress as a factor increasing susceptibility to diet-induced liver damage. Full article

Background/Objectives: A novel 3D-printed, bioresorbable bone graft, made of nanohydroxyapatite (nHAP) covered by poly(lactide-co-glycolide) (PLGA), showed strongly expressed osteoinductive properties in our previous investigations. The current study examines its application in the dual regeneration of bone and cartilage by combining with nHAP gel obtained by nHAP enrichment with hydroxyethyl cellulose, sodium hyaluronate, and chondroitin sulfate. Methods: In the in vitro part of the study, the mitochondrial activity and osteogenic and chondrogenic differentiation of stem cells derived from apical papilla (SCAPs) in the presence of nHAP gel were investigated. For the in vivo part of the study, three rabbits underwent segmental osteotomies of the lateral condyle of the femur, and defects were filled by 3D-printed grafts customized to the defect geometry. Results: In vitro study revealed that nHAP gel displayed significant biocompatibility, substantially increasing mitochondrial activity and facilitating the osteogenic and chondrogenic differentiation of SCAPs. For the in vivo part of the study, after a 12-week healing period, partial resorption of the graft was observed, and lamellar bone tissue with Haversian systems was detected. Histological and stereological evaluations of the implanted grafts indicated successful bone regeneration, marked by the infiltration of new bone and cartilaginous tissue into the graft. The existence of osteocytes and increased vascularization indicated active osteogenesis. The hyaline cartilage near the graft showed numerous new chondrocytes and a significant layer of newly formed cartilage. Conclusions: This study demonstrated that tailored 3D-printed bone grafts could efficiently promote the healing of substantial bone defects and the formation of new cartilage without requiring supplementary biological factors, offering a feasible alternative for clinical bone repair applications. Full article

This study evaluates the perfection of the crystal structure of single-crystal turbine blade castings made from the CMSX-4 nickel superalloy. The analysis included primary and secondary crystal orientation measurements using the Ω-scan method and the novel OD-EFG X-ray diffractometer. The selected microstructural parameters of the single crystals were also analyzed, including the assessment of stereological parameters and the degree of porosity. A creep test was performed according to standard procedures and under conditions simulating real operational environments. The model single-crystal turbine blades were manufactured using the Bridgman–Stockbarger method, with variable withdrawal rates of 1 and 3 mm/min. Heat treatment of the single-crystal castings involved solution treatment followed by double aging. The evaluation of structural perfection was carried out in three states: as-cast, after solution heat treatment, and after double aging. The crystallographic orientation of the blades was determined on both the airfoil and the root part. The study determined how crystallographic orientation and microstructural parameters influence the creep resistance of the castings. It was found that in the as-cast condition, the greatest influence on high creep strength has a small deviation of the primary and constant value of secondary crystal orientation along the height of the blade casting. After heat treatment, the highest creep resistance was obtained for the blade manufactured at a withdrawal rate at 1 mm/min. Full article

Nonarteritic anterior ischemic optic neuropathy (NAION) is an ischemic lesion of the anterior optic nerve (ON), currently untreatable due to the length of time from symptom onset until treatment. We evaluated angiotensin-(1-7) (Ang-(1-7)): the MAS1-receptor ligand, as a possible NAION treatment using the rodent NAION model (rNAION). Long-Evans rats were unilaterally rNAION-induced. One-day post-induction, lesion severity was quantified via optic nerve head (ONH) edema using spectral domain optical coherence tomography. Animals meeting rNAION induction criteria were randomized into (1) Subcutaneous Ang-(1-7) infusion for 28 days and (2) Vehicle. Visual function was assessed using both visual acuity and flash visual evoked potentials (fVEP). Tissues were collected >30d and RGC neurons were quantified by stereology. ONs were histologically examined for inflammation. Ang-(1-7) improved post-rNAION visual function. Ang-(1-7)-treated animals showed improved visual acuity (ANCOVA: p = 0.0084) and improved fVEP amplitudes (ANCOVA: p = 0.0378) vs vehicle controls. The relative degree of improvement correlated with ONH edema severity. Treated animals showed trends towards increased RGC survival, and reduced optic nerve inflammatory cell infiltration. Ang-(1-7) is the first agent effective ≥1 day after rNAION induction. Ang-(1-7) type agonists may be useful in improving long-term function and neuronal survival in clinical NAION and other forms of white matter ischemia. Full article

In recent years, there has been significant interest in the development of self-compacting concrete (SCC). This study views SCC as a two-phase composite material and introduces a new aggregate spacing coefficient model based on the concept of Fullman’s mean free path and stereological theory. The validity of the aggregate spacing coefficient model was verified. The relationship between the fine and coarse aggregate coefficients and the properties of SCC are revealed. The results show that the slump and slump flow of SCC increase as the fine and coarse aggregate coefficients increase. The coarse aggregate spacing coefficient has a significant influence on the compressive strength and drying shrinkage of SCC. A significant linear relationship between the coarse aggregate spacing coefficient and SCC dry shrinkage properties is revealed. Compared to the conditional mixing proportion method, which considers the aggregate volume as a control factor, the aggregate spacing coefficient takes into account the aggregate volume and gradation, which can more accurately reflect the characteristics of the aggregate. Meanwhile, this new perspective on the macroscopic composition of SCC provides insights into the controlling factors of its performance. Full article

This article introduces a novel approach for assessing microstructure, particularly its degradation after extended operation. The authors focus on creep processes in power plant components, highlighting the importance of diagnostics in this field. This article emphasizes the value of combining traditional microstructure observation techniques with image analysis. A non-destructive method of evaluating microstructure parameters (matrix replicas) is presented, and its accuracy is evaluated against the conventional destructive method. The assessment utilizes quantitative data derived from classical stereological principles and image analysis. Parameters like mean chord length, relative surface area, mean cross-sectional area, and mean equivalent diameter are compared for replica and metallographic specimens. The results show that the replica method accurately reproduces the microstructure. In their conclusions, the authors highlight the importance of developing visual methods alongside the application of artificial intelligence while indicating the challenges in achieving this goal. Full article

Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder. However, the core biology of the disorder that leads to the hypofunctioning of the cerebral dopaminergic network requires further elucidation. We investigated midbrain synaptic changes in male rats exposed to repeated hypoxia during the equivalent of extreme prematurity, which is a new animal model of the hyperactive/impulsive presentation of ADHD. We used a novel combination of a lentiviral vector, peroxidase-immunonanogold double-labelling, three-dimensional serial section transmission electron microscopy and stereological techniques to investigate the synapses formed between GABAergic axons of the rostromedial tegmental nucleus (RMTg) and dopaminergic neurons of the posterior ventral tegmental area (pVTA). This is a key site that sends extensive dopaminergic projections to the forebrain. We also compared the results to our previous study on a schizophrenia risk factor that produces cerebral hyperdopaminergia. In total, 117 reconstructed synapses were compared. Repeated hypoxic rats had a significantly thicker (22%) and longer (18%) postsynaptic density at RMTg GABAergic-pVTA dopaminergic synapses compared to their controls. These results were opposite to those previously observed in rats exposed to a schizophrenia risk factor. These findings for repeated hypoxic rats suggest that the enhanced inhibition of pVTA dopaminergic neurons may contribute to hypodopaminergia in ADHD motor hyperactivity. Synaptic triads, a key component of pVTA circuitry, were not detected in repeated hypoxic rats, indicating a marked deficit. The current knowledge may guide development in males of novel, site-specific ADHD drugs, which is necessary due to the rising prevalence of ADHD, the chronic nature of ADHD symptoms and the limitations of the currently available medications. Full article

The air void system in concrete significantly affects its mechanical, thermal, and frost durability properties. This study explored the use of ChatGPT, an AI tool, to generate Python code for analyzing air void parameters in hardened concrete, such as total air void content (A), specific surface (α), and air void spacing factor (L). Initially, Python scripts were created by requesting ChatGPT-3.5 to convert MATLAB scripts developed by Fonseca and Scherer in 2015. The results from Python closely matched those from MATLAB when applied to polished sections of seven different concrete mixes, demonstrating ChatGPT’s effectiveness in code conversion. However, generating accurate code without referencing the original MATLAB scripts required detailed prompts, highlighting the need for a strong understanding of the test method. Finally, a Python script was applied to modify void reconstruction in 2D images into 3D by stereology, and comparing this with (3D) CT scanner results, showing comparable results. Full article

Recently, it has been hypothesized that alpha-synuclein protein strain morphology may be associated with clinical subtypes of alpha-synucleinopathies, like Parkinson’s disease and multiple system atrophy. However, direct evidence is lacking due to the caveat of conformation-specific characterization of protein strain morphology. Here we present a new cell model based in vitro method to explore various alpha-synuclein (αsyn) aggregate morphotypes. We performed a spectroscopic investigation of the HEK293 cell model, transfected with human wildtype-αsyn and A53T-αsyn variants, using the amyloid fibril-specific heptameric luminescent oligomeric thiophene h-FTAA. The spectral profile of h-FTAA binding to aggregates displayed a blue-shifted spectrum with a fluorescence decay time longer than in PBS, suggesting a hydrophobic binding site. In vitro spectroscopic binding characterization of h-FTAA with αsyn pre-formed fibrils suggested a binding dissociation constant K_d < 100 nM. The cells expressing the A53T-αsyn and human wildtype-αsyn were exposed to recombinant pre-formed fibrils of human αsyn. The ensuing intracellular aggregates were stained with h-FTAA followed by an evaluation of the spectral features and fluorescence lifetime of intracellular αsyn/h-FTAA, in order to characterize aggregate morphotypes. This study exemplifies the use of cell culture together with conformation-specific ligands to characterize strain morphology by investigating the spectral profiles and fluorescence lifetime of h-FTAA, based upon its binding to a certain αsyn aggregate. This study paves the way for toxicity studies of different αsyn strains in vitro and in vivo. Accurate differentiation of specific alpha-synucleinopathies is still limited to advanced disease stages. However, early subtype-specific diagnosis is of the utmost importance for prognosis and treatment response. The potential association of αsyn aggregates morphotypes detected in biopsies or fluids to disease phenotypes would allow for subtype-specific diagnosis in subclinical disease stage and potentially reveal new subtype-specific treatment targets. Notably, the method may be applied to the entire spectrum of neurodegenerative diseases by using a combination of conformation-specific ligands in a physicochemical environment together with other types of polymorphic amyloid variants and assess the conformation-specific features of various protein pathologies. Full article