Dorsal Region Research Articles

Relationship Between Resting State Functional Connectivity and Reading-Related Behavioural Measures in 69 Adults

Abstract In computational models of reading, written words can be read using print-to-sound and/or print-to-meaning pathways. Neuroimaging data associate dorsal stream regions (left posterior occipitotemporal cortex, intraparietal cortex, dorsal inferior frontal gyrus [dIFG]) with the print-to-sound pathway and ventral stream regions (left anterior fusiform gyrus, middle temporal gyrus) with the print-to-meaning pathway. In 69 typical adults, we investigated whether resting state functional connectivity (RSFC) between the visual word form area (VWFA) and dorsal and ventral regions correlated with phonological (nonword reading, nonword repetition, spoonerisms), lexical-semantic (vocabulary, sensitivity to morpheme units in reading), and general literacy (word reading, spelling) skills. VWFA activity was temporally correlated with activity in both dorsal and ventral reading regions. In pre-registered whole-brain analyses, spoonerisms performance was positively correlated with RSFC between the VWFA and left dorsal regions (dIFG, superior parietal and intraparietal cortex). In exploratory region-of-interest analyses, VWFA-dIFG connectivity was also positively correlated with nonword repetition, spelling, and vocabulary. Connectivity between the VWFA and ventral stream regions was not associated with performance on any behavioural measure, either in whole-brain or region-of-interest analyses. Our results suggest that tasks such as spoonerisms and spellings, which are both complex (i.e., involve multiple subprocesses) and have high between-subject variability, provide greater opportunity for observing resting-state brain-behaviour associations. However, the complexity of these tasks limits the conclusions we can draw about the specific mechanisms that drive these associations. Future research would benefit from constructing latent variables from multiple tasks tapping the same reading subprocess.

Activation of androgen receptor-expressing neurons in the posterior medial amygdala is associated with stress resistance in dominant male hamsters

Social stress is a negative emotional experience that can increase fear and anxiety. Dominance status can alter the way individuals react to and cope with stressful events. The underlying neurobiology of how social dominance produces stress resistance remains elusive, although experience-dependent changes in androgen receptor (AR) expression is thought to play an essential role. Using a Syrian hamster (Mesocricetus auratus) model, we investigated whether dominant individuals activate more AR-expressing neurons in the posterior dorsal and posterior ventral regions of the medial amygdala (MePD, MePV), and display less social anxiety-like behavior following social defeat stress compared to subordinate counterparts. We allowed male hamsters to form and maintain a dyadic dominance relationship for 12 days, exposed them to social defeat stress, and then tested their approach-avoidance behavior using a social avoidance test. During social defeat stress, dominant subjects showed a longer latency to submit and greater c-Fos expression in AR+ cells in the MePD/MePV compared to subordinates. We found that social defeat exposure reduced the amount of time animals spent interacting with a novel conspecific 24 h later, although there was no effect of dominance status. The amount of social vigilance shown by dominants during social avoidance testing was positively correlated with c-Fos expression in AR+ cells in the MePV. These findings indicate that dominant hamsters show greater neural activity in AR+ cells in the MePV during social defeat compared to their subordinate counterparts, and this pattern of neural activity correlates with their proactive coping response. Consistent with the central role of androgens in experience-dependent changes in aggression, activation of AR+ cells in the MePD/MePV contributes to experience-dependent changes in stress-related behavior.

Functional Connectivity of Moral Cognition and Traits of Psychopathy in Youth: An Analysis of the Scientific Literature

The aim of the study is to analyze the scientific literature and evidence on the mechanisms of functional connectivity involved in moral cognition processes in youth with psychopathy traits. Scientometric methods of citation networks based on graph theory were used. Bibliometrix, Sci2 Tool, and Gephi were used for the analysis. It was found that the dorsal and ventral regions of the prefrontal cortex, orbitofrontal cortex, amygdala, hippocampus, angular gyrus, anterior cingulate and temporal cortex evidence functional alterations in young people with psychopathic traits. It was also reported that graymatter concentration in the left posterior and right anterior cingulate are possible endophenotypes of psychopathic traits. The theoretical, empirical, and legal implications of a moral neural perspective of psychopathy andantisocial behavior are discussed. The results demonstrated that psychopathic traits, which occasionally lead to criminal and violent behaviors, have a neurobiological basis related to moral cognition processes. However, a neuronal moral model has theoretical and practical limitations, as well as legal implications for free will and moral agency capacity.

Associations between day and night-shifts, work-related musculoskeletal symptoms and absenteeism in the manufacturing industry

Objectives. Associations between shift-work, musculoskeletal symptoms and absenteeism are poorly investigated in the manufacturing industry. This study aimed to investigate associations between working schedule, musculoskeletal symptoms and days of absenteeism among pulp and paper industry workers. Methods. Musculoskeletal symptoms of 904 workers were assessed through the Nordic Musculoskeletal Questionnaire. χ 2 tests assessed associations between being a day-worker or shift-worker, the prevalence of musculoskeletal symptoms and days of absenteeism. Results. A significant association was found between working schedule and symptoms in the lower back in the last 12 months, with shift-workers presenting higher prevalence than day-workers (p = 0.022). Significant associations were also found between days of absenteeism and symptoms in the shoulders (p = 0.002), which mostly led to absenteeism of 100–365 days; elbows (p < 0.001), wrists/hands (p = 0.045) and ankles/feet (p = 0.042), which produced absenteeism mostly of 25–99 days; and dorsal region (p = 0.001), which mainly led to absenteeism of 10–24 days. No associations were found between working schedule and days of absenteeism (p = 0.265). Conclusion. Shift-work is associated with increased prevalence of lower back symptoms, but seems not to influence days of absenteeism. Shoulders seem to be the region leading to higher days of absenteeism, followed by elbows, wrists/hands, ankles/feet and the dorsal region.

Thick Skin on the Dorsal Spine in Osteoproliferative Disease: Ossification of the Posterior Longitudinal Ligament and Diffuse Idiopathic Skeletal Hyperostosis.

Background Although the correlation between reduced skin thickness and reduced bone density has been investigated, no study has evaluated skin thickness and osteoproliferative diseases, including ossification of the posterior longitudinal ligament (OPLL) and diffuse idiopathic skeletal hyperostosis (DISH). Methodology This retrospective cohort study consisted of 99 consecutive patients aged ≥60 years treated for spinal surgery at our hospital between January 2022 and March 2023. Skin thickness was measured at the dorsal side of the cervical, thoracic, and lumbar vertebrae on the sagittal cross-section image of whole-spine CT. Based on the median value, skin thickness was categorized into two groups based on a median thickness of 4 mm. Bone mineral density (BMD) was assessed. The sum of the vertebral body and intervertebral bridging osteophytes of the anterior longitudinal and posterior longitudinal ligament were defined as the OALL index and OPLL index. Serum levels of bone metabolism-related markers, such as tartrate-resistant acid phosphatase type 5b, procollagen I N-propeptide, 25-hydroxyvitamin D, and periostin, were measured. To assess the association between skin thickness and imaging findings, we calculated the adjusted odds ratios, adjusting for age, sex, and body mass index (BMI) and using univariate and multivariate logistic regression analyses. Results No significant differences were found in skin thickness in the three dorsal regions of the cervical, thoracic, and lumbar spine (median = 3.3 mm versus 3.5 mm versus 3.4 mm, p = 0.357) and bone metabolism-related markers. Adjusting for age, sex, and BMI, cervical, thoracic, and lumbar skin thicknesses were related to DISH, the OPLL index, and the OPLL and OPLL index, respectively. Conclusions Skin thickness did not correlate with BMD but with the amount of spinal ossification. A correlation was found between skin thickness and vertebral and intervertebral ossification; vertebral osteophytes, OPLL, and DISH may be more common in thicker skin.

Respiratory internal kinematics of the tongue base and soft palate in obese minipigs with obstructive sleep apnea.

It is largely unknown how the tongue base and soft palate deform to alter the configuration of the oropharyngeal airway during respiration. This study is to address this important gap. After live sleep monitoring of five Yucatan and two Panepinto minipigs to verify obstructive sleep apnea (OSA), eight and four ultrasonic crystals were implanted into the tongue base and soft palate to circumscribe a cubic and square region, respectively. The 3D and 2D deformational changes of the circumscribed regions were measured simultaneously with electromyographic activity of the oropharyngeal muscles during spontaneous respiration under sedated sleep. The results indicated that both obese Yucatan and Panepinto minipigs presented spontaneous OSA, but not in threenonobese Yucatan minipigs. During inspiration, the tongue base showed elongation in both dorsal and ventral regions but thinning and thickening in the anterior and posterior regions, respectively. The widths showed opposite directions, widening in the dorsal but narrowing in the ventral regions. The soft palate expanded in both length and width. Compared to normal controls, obese/OSA ones showed similar directions of deformational changes, but the magnitude of change was two times larger in the tongue base and soft palate, and obese/OSA Panepinto minipigs presented 10 times larger changes in all dimensions of both the tongue base and the soft palate. The distance changes between the dorsal surface of tongue base and soft palate during inspiration increased in normal but decreased in obese OSA minipigs.

Seeing across variable ecological and social environments: comparative eye morphology of marine and terrestrial hermit crabs (Decapoda: Anomura: Coenobitidae, Paguridae)

Abstract Vision is a ubiquitous sensory modality adapted to vastly different environments, which place variable selection pressures on both macro- and microscopic dimensions of external eye morphology. The hermit crab clade (Crustacea: Decapoda: Anomura) spans environments from sea to land, yet, no systematic comparisons in eye morphology have been made between any species. We compared three species of hermit crabs inhabiting different ecological and social environments: two terrestrial species, one of which (Coenobita compressusH. Milne Edwards, 1837) is highly social and inhabits a flat, open diurnal habitat, and another (C. clypeatus Herbst, 1791) is its sister species that inhabits a rugged forested nocturnal habitat; and a third (Pagurus longicarpusSay, 1817) inhabits a marine intertidal habitat and is less social. We compared macroscopic eye morphology between species as well as microscopic differences in ommatidium-facet density and diameter within eyes. We found that eye dimensions (length, width, and thickness), but not overall volume, differed significantly between marine and terrestrial species. Furthermore, the highly social C. compressus had a significantly larger eye volume compared to its sister species, C. clypeatus, which is not as social. Larger eyes in C. compressus might be linked to its social lifestyle, where vision has been shown to be critical to finding conspecifics. All three species had a higher density of facets in the ventral compared to dorsal region of the eye. Our comparisons of external eye morphology revealed microscopic similarities but notable macroscopic variation between species, thus laying a foundation for future phylogenetically controlled tests within this species-rich clade, including comparisons of internal eye morphology.

Dung beetle populations's morphology show evidence of isolation in southern Brazil islands

AbstractInsects in islands may undergo morphological variations related to the geographic isolation faced by their populations. This isolation on insular biota can vary according to the history and characteristics of the islands, as well as the dispersal ability of each species. We investigated the existence of morphological variations in the populations of the Canthon rutilans cyanescens dung beetle from the southern Brazil islands and the nearby mainland. Dung beetles were sampled from December/2020 to April/2021 from five Islands in the Santa Catarina Archipelago and on the mainland through samplings with baited live traps. With geometric morphometry analyses and individuals from each population we compared the body size using an Analysis of Variance and body shape using a Discriminant Analysis with cross‐validation test, followed by a Canonical Variable Analysis to visualize the populations in morphometric space. We found a significant difference in the body length: the population of Ratones Grande Island has smaller individuals than the populations of the mainland, Dona Francisca Island, and Peri on Santa Catarina Island. We also observed that the body shape of the population of Campeche Island differs from the populations of Arvoredo Island and Dona Francisca Island, with a slightly oval body, a larger dorsal region, and a retracted abdomen. These results are consistent with the hypothesis that the populations found on the islands may have remained there since their formation after the Last Glacial Maximum. The isolation and the absence of connectivity between the populations would explain why some islands have populations with distinct morphology.Abstract in Portuguese is available with online material.

A potentially endangered new species of the genus Rowlandius (Arachnida: Schizomida: Hubbardiidae) from Northeastern Brazil

A new species of schizomid, Rowlandius ufpi sp. nov., is described based on individuals collected in gallery and riverine forests in a Cerrado-Caatinga ecotone in northeastern Brazil. Rowlandius ufpi sp. nov. is the sixth species of the genus found in Brazil and raises to 62 the number of described species of genus Rowlandius. This is also the first epigean species of Rowlandius inhabiting a Brazilian dry forest leaf litter. Males of Rowlandius ufpi sp. nov. can be easily distinguished from other conspecifics by the presence of three depressions in the dorsal region of the flagellum, with the posteromedian depression located in the posterior third part of the dorsal surface. The females of Rowlandius ufpi sp. nov. are recognized by the sub-square shaped spermathecae with short median lobes.

Wound Healing Effects of Liposomal Nanocurcumin and PL Pro Nanocurcumin on Thermal Burn and Skin Ulcer

Background Burn injuries and skin ulcers are important health problems resulting in physical and psychological scars and chronic disabilities. This study investigated the wound-healing effects of liposomal nanocurcumin and PL pro nanocurcumin on thermal burns in rats and doxorubicin-induced skin ulcers in mice and their systemic toxicity. Methods Having subjected to a cylindrical hot steel rod onto the dorsum, burned lesions were covered topically with silver sulfadiazine/liposomal nanocurcumin/PL pro nanocurcumin twice a day for 21 days. Besides, the other skin lesions which were induced by a single intradermal injection of doxorubicin on the dorsal region were topically administered with dimethyl sulfoxide/liposomal nanocurcumin/PL pro nanocurcumin twice a day for 21 days. Results The results indicated that liposomal nanocurcumin and PL pro nanocurcumin significantly reduced the wound size, increased the hydroxyproline content in animals’ skin, and improved the histopathological structure of the affected tissues. Specifically, liposomal nanocurcumin demonstrated better healing results than PL pro nanocurcumin on thermal burns. Furthermore, topical administration of liposomal and PL pro nanocurcumin was deemed not to exert any systemic toxicity to the wounded animals by not influencing considerably the hematological parameters and renal and hepatic functions and altering the histology of the liver and kidney. Additionally, liposomal nanocurcumin and PL pro nanocurcumin with average sizes of 206 nm and 344 nm were well-dispersed in water, accentuating that the disadvantages of limited water solubility have been overcome. Conclusion Thus, liposomal nanocurcumin and PL pro nanocurcumin exerted effective effects on burned wounds and skin ulcers whilst triggering no systemic toxicity in wounded animals.

Hydrogels based on galactomannan and κ-carrageenan containing immobilized biomolecules for in vivo thermal-burn wound treatment

Hydrogels based on natural polysaccharides have demonstrated efficacy in epithelial recovery from cutaneous burn wounds. Here, we prepared a double-network hydrogel consisting of galactomannan (from Cassia grandis seeds) and κ-carrageenan (commercially sourced), cross-linked with CaCl2, as a matrix for immobilizing lactoferrin and/or Cramoll, aiming at its applicability as dressings for second-degree burn wounds. The formulations obtained [H — hydrogel, HL — hydrogel + lactoferrin, HC — hydrogel + Cramoll and HLC — hydrogel + lactoferrin + Cramoll] were analyzed rheologically as well as in terms of their stability (pH, color, microbial contamination) for 90 days. The burn was created with an aluminum bar (97 ± 3 °C) in the dorsal region of Wistar rats and subsequently treated with hydrogels (H, HL, HC, HLC) and control saline solution (S). The burn was monitored for 3, 7 and 14 days to evaluate the efficacy of the hydrogels in promoting wound healing. The hydrogels did not reveal significant pH or microbiological changes; there was an increase in brightness and a reduction in opacity for H. The rheological analysis confirmed the gel-like viscoelastic signature of the systems without substantial modification of the basic rheological characteristics, however HLC proved to be more rigid, due to rheological synergy when combining protein biomolecules. Macroscopic analyses confirmed centripetal healing with wound contraction: S < H < HC < HL < HLC. Histopathological analyses showed that hydrogel-treated groups reduced inflammation, tissue necrosis and fibrosis, while promoting re-epithelialization with focal acanthosis, especially in HLC due to a positive synergistic effect, indicating its potential as a promising therapy in the repair of burns.

Injection rate, scanning position, and values of parameters on pulmonary computed tomography perfusion in normal Beagles.

This study evaluated the effects of scanning position and contrast medium injection rate on pulmonary CT perfusion (CTP) images in healthy dogs. 7 healthy Beagles. Experiments involved 4 conditions: dorsal and sternal recumbency at 2.5 mL/s (first) and sternal recumbency with additional rates of 1.5 and 3.5 mL/s (second). Various parameters, including the initial time of venous enhancement (Tv), peak time of arterial enhancement (PTa), and peak enhancement values of the artery, were measured. The PTa to Tv interval was calculated. Perfusion mapping parameters (pulmonary blood flow, pulmonary blood volume, mean transit time, time to maximum, and time to peak) were determined in different lung regions (left and right dorsal, middle, and ventral). There are significant variations in most perfusion mapping parameters based on the pulmonary parenchymal location. Dorsal recumbency had a lower peak value of arterial enhancement than sternal recumbency. Pulmonary blood flow in the dorsal region and mean transit time and time to maximum in all regions showed no significant differences based on position. Pulmonary blood volume and time to peak varied with scanning position. The PTa to Tv interval did not differ based on the injection rate, but the injection time at 1.5 mL/s was longer than at other rates. All perfusion mapping parameters of the ventral region increased with higher injection rates. The recommended CTP imaging approach in dogs is a low injection rate of 1.5 mL/s in the sternal recumbency. This study provides reference ranges for perfusion parameters based on the pulmonary parenchymal location, contributing to the acquisition and application of pulmonary CTP images for differential diagnosis in small-breed dogs.

Prediction of subthalamic stimulation efficacy on isolated dystonia via support vector regression

IntroductionDeep brain stimulation (DBS) of subthalamic nucleus (STN) has been well-established and increasingly applied in patients with isolated dystonia. Nevertheless, the surgical efficacy varies among patients. This study aims to explore the factors affecting clinical outcomes of STN-DBS on isolated dystonia and establish a well-performed prediction model. MethodsIn this prospective study, thirty-two dystonia patients were recruited and received bilateral STN-DBS at our center. Their baseline characteristics and up to one-year follow-up outcomes were assessed. Implanted electrodes of each subject were reconstructed with their contact coordinates and activated volumes calculated. We explored correlations between distinct clinical characteristics and surgical efficacy. Those features were then trained for the model in outcome prediction via support vector regression (SVR) algorithm and testified through cross-validation. ResultsPatients demonstrated an average clinical improvement of 56 ± 25 % after STN-DBS, significantly affected by distinct symptom forms and activated volumes. The optimal targets and activated volumes were concentratedly located at the dorsal posterior region to STN. Most patients had a rapid response to STN-DBS, and their motor score improvement within one week was highly associated with long-term outcomes. The trained SVR model, contributed by distinct weights of features, could reach a maximum prediction accuracy with mean errors of 11 ± 7 %. ConclusionSTN-DBS demonstrated significant and rapid therapeutic effects in patients with isolated dystonia, by possibly affecting the pallidofugal fibers. Early improvement highly indicates the ultimate outcomes. SVR proves valid in outcome prediction. Patients with predominant phasic and generalized symptoms, shorter disease duration, and younger onset age may be more favorable to STN-DBS in the long run.

Anatomy and ultrastructural details of the eye of the passalid beetle Ceracupes yui Okano 1988 (Scarabaeoidea; Passalidae)

One of the least studied eyes of any beetle taxon are those of the scarabaeoid family Passalidae. Some members of this family of around 600 species worldwide are known to have superposition eyes (Aceraius grandis; A. hikidai) while others have apposition eyes (Cylindrocaulus patalis; Ceracupes yui). In C. yui of nearly 3 cm body length (this paper) the retinal layer is very thin and occupies approximately half of an ommatidium's total length, the latter amounting to 284 and 266 μm in the respective dorsal and ventral eye regions. The two eye regions are almost completely separated by a prominent cuticular canthus, a feature usually associated with the presence of a tracheal tapetum, a clear-zone between dioptric and light-perceiving structures and a regular array of smooth facets. In C. yui the facets are smooth (but not very regular) and a tracheal tapetum and a clear-zone are absent. The rhabdoms, formed by 8–9 retinula cells, are complicated, multilobed structures with widths and lengths of around 15 and 80 μm, respectively. The combination of some superposition and mostly apposition eye features, e.g., extensive corneal exocones, relatively small number of ommatidia, absence of a clear-zone and tracheal bush, suggest an adaptation of this species' eye to the fossorial lifestyle of C. yui, and, thus, a manifestation of the passalid eye's plasticity.

Determination of optimal positive end-expiratory pressure using electrical impedance tomography in infants under general anesthesia: Comparison between supine and prone positions.

This study determined the optimal positive end-expiratory pressure levels in infants in supine and prone positions under general anesthesia using electrical impedance tomography (EIT). This prospective observational single-centre study included infants scheduled for surgery in the prone position. An electrical impedance tomography sensor was applied after inducing general anesthesia. The optimal positive end-expiratory pressure in the supine position was determined in a decremental trial based on EIT and compliance. Subsequently, the patient's position was changed to prone. Electrical impedance tomography parameters, including global inhomogeneity index, regional ventilation delay, opening pressure, the centre of ventilation, and pendelluft volume, were continuously obtained up to 1 h after prone positioning. The optimal positive end-expiratory pressure in the prone position was similarly determined. Data from 30 infants were analyzed. The mean value of electrical impedance tomography-based optimal positive end-expiratory pressure in the prone position was significantly higher than that in the supine position [10.9 (1.6) cmH2O and 6.1 (0.9) cmH2O, respectively (p < .001)]. Significant differences were observed between electrical impedance tomography- and compliance-based optimal positive end-expiratory pressure. Peak and mean airway, plateau, and driving pressures increased 1 h after prone positioning compared with those in the supine position. In addition, the centre of ventilation for balance in ventilation between the ventral and dorsal regions improved. The prone position required higher positive end-expiratory pressure than the supine position in mechanically ventilated infants under general anesthesia. EIT is a promising tool to find the optimal positive end-expiratory pressure, which needs to be individualized.

A new insight into the pigmentation of the three-spined stickleback exposed to oxidative stress: day and night study

The diverse and changing pigmentation of the skin allows fish to adapt to environmental conditions for survival and communication with conspecifics. However, various physical and chemical environmental factors, including pollutants, affect fish coloration. Therefore, the implementation of an analysis of skin pigmentation has been considered in fish well-being and ecotoxicological studies. A physiological color change is achieved by the motility of melanin-containing organelles: they aggregate into the perikaryon or disperse throughout the cytoplasm of melanophores in response to various stimuli. In our study, we addressed the issue of implementing the analysis of pigment dispersion in melanophores in stickleback skin to assess the response of fish to oxidative stress. We examined pigment dispersion in day and night skin samples collected from the dorsal, lateral and ventral regions. The degree of pigment dispersion we assessed by the melanophore index. The total number of melanophores counted in the defined skin area was significantly higher in the night samples than in the day samples. Only in day samples of dorsal skin we observed the significant changes in pigment dispersion after exposure to stress: melanin was predominantly in the aggregated state. In the night samples, we did not report any response to stress in any part of the skin. Examination of pigment dispersion in melanophores in stickleback skin can be useful for assessing the welfare of fish and detecting toxic agents in the environment, but under specified conditions: in sticklebacks, it is analysis of dorsal skin during the day.

Immunohistochemistry of the nasal cavity-associated lymphoid tissue in the dolphin (Stenella coeruleoalba, Meyen 1833).

The striped dolphin (Stenella coeruleoalba) is a medium-sized pelagic dolphin with a single external nasal opening (blowhole) located in the rostral and dorsal regions of the skull. The nasal cavity is divided into three sections: the olfactory, respiratory, and vestibular areas. The surface epithelium lining the regio vestibularis is the first tissue in the nose to be directly affected by environmental antigens. Cetaceans have a significant amount of mucosa-associated lymphoid tissue (MALT) located throughout their bodies. The lymphoid tissue found in the nasal mucosa is known as nose- or nasopharynx-associated lymphoid tissue (NALT). NALT has not yet been studied in dolphins, but it has been identified and documented in humans and laboratory rodents. This study utilized toll-like receptor 2 (TLR2), CD4, Langerin/CD207, and inducible nitric oxide synthase to characterize, for the first time, immune cells in the mucosal regio vestibularis of the S. coeruleoalba nasal cavity using confocal microscopy immunofluorescence techniques. The findings revealed scattered immune cells immunoreactive to the tested antibodies, present in both the epithelial tissue lining the nasal cavity vestibulum and the underlying connective tissue. This study enhances our comprehension of the immune system of cetaceans. RESEARCH HIGHLIGHTS: This study provides new insights into NALT in S. coeruleoalba. This research deepens the knowledge of the skin of cetaceans.

Morphofunctional changes in ventral and dorsal hippocampus in adult rats after chronic mild stress: a preclinical experimental study

Background. Stressful influences, depending on their severity and duration, can cause the development of pathological conditions. Repeated episodes of stress cause functional and structural changes in the central nervous system and can cause the development of depressive conditions. Depression is one of the leading mental illnesses. One of the most stress-sensitive brain structures is the hippocampus. Objective. To study is to evaluate structural changes in the hippocampus, which is considered as a heterogeneous structure with separate dorsal and ventral regions, to evaluate the expression of inducible nitric oxide synthase, endothelial nitric oxide synthase, serine racemase, synaptophysin in a mild stress model.Methods. A study of the effects of mild stress was carried out on 16 adult male Wistar rats (age 12 months, body weight 350–400 g). After acclimatization, the rats were divided into two equal groups (n = 8): intact (control) and stressed. When keeping animals, modeling and removing them from the experiment, we were guided by the Regulations for Carrying Out Work Using Laboratory Animals and the Declaration of Helsinki. Experimental modeling of depression in animals was induced by mild stress exposure for 7 days (30 minutes daily). Euthanasia was performed in a CO2 incubator. The brain was fixed in neutral buffered 10% formalin. Paraffin sections were made in the frontal plane, stained with hematoxylin and eosin, thionin using the Nissl method and examined at a level from –2.40 to –3.96 mm relative to bregma using an Axio Lab A1 microscope (Carl Zeiss Microscopy GmbH, Germany). Photo documentation was carried out with an AxioCam 105 color camera (Carl Zeiss Microscopy GmbH, Germany). Using the Image Analysis module of the ZEN 1.1.2.0 program (Carl Zeiss Microscopy GmbH, Germany) in the pyramidal layer of the hippocampus. Statistical analysis was performed with Microsoft Office Excel 2016 (Microsoft, USA) and Prism 6 (GraphPad Software Inc., USA). Comparisons of two conditions were made by nonparametric Mann-Whitney-U test to avoid a statistical bias of unequal data distribution. The level of significance was set at p &lt; 0.05. The summarized data were presented as a as mean ± standard error of mean.Results. Functional research methods and assessment of pathological changes in hippocampal neurons are presented. An increase in the relative number of wrinkled hyperchromatic pyramidal neurons in the dorsal cornu ammonis field 3 in stressed rats was noted by 23.6% (p &lt; 0.05) compared to the control. There was an increase in the relative number of inducible nitric oxide synthase-immunopositive neurons in the dorsal cornu ammonis field 3 by 40% ( p &lt; 0.05) and the relative area of inducible nitric oxide synthase-immunoreactive material by 35% (p &lt; 0.05) in the pyramidal layer of cornu ammonis field 3 in stressed rats. A decrease in the relative area of synaptophysin-immunopositive material in stressed rats was found in the ventral cornu ammonis field 3 compared to the control group by 16.8% (p &lt; 0.05); decrease in the relative area of serine racemase-immunopositive material in dorsal cornu ammonis field 3 by 4.3% (p &lt; 0.05) and ventral cornu ammonis field 3 by 7.8% (p &lt; 0.05).Conclusion. The results of the study demonstrate that mild stress is an adequate model of depression in rats. In animals exposed to mild stress, pronounced morphological signs of damage to hippocampal neurons were revealed; motor and indicative exploratory activity decreases. Differences were found in morphofunctional changes in the dorsal and ventral parts of the hippocampus under the influence of mild stress. In cornu ammonis field 3 of the dorsal hippocampus, in contrast to the ventral section, more pronounced signs of damage to pyramidal layer neurons were observed. The increase in the relative number of inducible nitric oxide synthase-immunopositive neurons and the relative area of inducible nitric oxide synthase-immunoreactive material in the cornu ammonis field 3 pyramidal layer in stressed rats indicates an increase in nitric oxide production and the participation of nitrooxide-dependent free radical mechanisms of damage to hippocampal neurons. The decrease in the relative area of synaptophysin-immunoreactive material in stressed rats may contribute to changes in synaptic plasticity. A decrease in the relative area of serine racemase-immunoreactive material in the dorsal and ventral parts of cornu ammonis field 3 is considered to be a sign of a possible decrease in N-methyl-D-aspartate-dependent neurotransmission in the hippocampus under stress.

A comparative study of gelatin-based nanofiber and sponge wound dressings

Gelatin is a collagen-derived biopolymer with high biocompatibility, commonly used in the production of wound dressing materials. Gelatin-based wound dressings, obtained through different processing methods, come with their own advantages and disadvantages depending on their physical structure. In this study, the effects of gelatin wound dressing materials with two different morphologies on wound healing are investigated in detail. The study investigated that the preparation of gelatin-based wound dressing materials using two different methods, followed by their chemical characterization and examination of their effects on biocompatibility and wound healing. To comprehend the impact of nanofiber structure and porous sponge structure on the wound healing process, the chemical structure of the prepared wound dressings was analyzed using Fourier Transform Infrared Spectrophotometer (FTIR). The morphological structure was visualized through Scanning Electron Microscope (SEM), the thermal properties were determined using Thermogravimetric Analyzer (TGA) and Differential Scanning Calorimeter (DSC). Additionally, the in vivo wound healing effects of gelatin-based wound dressings with different structures were evaluated through macroscopic observation and histological analysis in a dorsal region wound-healing rat model, monitored for 21 days. It was observed that wound healing materials with desired nanofiber and porous sponge structures were successfully obtained based on the SEM analysis. The gelatin nanofiber dressing showed a randomly oriented, bead-free, and smooth morphology with an average fiber diameter of approximately 1250 ± 0.35 nm, while the crosslinked gelatin sponge dressing had pore sizes ranging from 20 to 160 μm, and interconnected pore structures. The chemical structure remained unaltered according to FTIR graphs and these results were further supported by DSC and TGA graphs. Results from in vitro biocompatibility studies indicated that the wound dressing materials were biologically compatible, non-toxic, and did not cause irritation or sensitivity to the skin. Regarding in vivo analysis, it was determined that gelatin dressing materials were functional in the wound healing process, without the use of any auxiliary materials.

Clinicopathological and Molecular Profile of Sellar Neurocytoma

Abstract Objective To investigate the clinical features, imaging characteristics, and molecular profile of sellar neurocytoma (SN). Methods Clinical, imaging, and pathological features of 11 cases of SN were retrospectively analyzed. Electron microscopy was performed in 5 cases. Molecular features were detected in tumor tissue by RNA sequencing, quantitative polymerase chain reaction, and immunohistochemistry. Results The clinical features of SN patients showed a high incidence of hyponatremia (73%, 8/11), and the tumors tended to invade the lateral side of the saddle area from preoperative imaging analysis. The tumors had positive NeuN, synaptophysin, neurofilament, somatostatin receptor 2 (SSTR2) immunohistochemistry staining. Tumor transcriptomic analysis suggested a new LMCD1-AS1:GRM7-AS1 fusion gene event and increased expression of 10 hypothalamus-secreted hormones in SN. Fifteen differentially expressed genes were verified for quantitative polymerase chain reaction verification. SSTR2 has been verified by immunohistochemistry. Conclusion Hyponatremia is the dominant clinical features of SN. Preoperative imaging suggests that growth toward the dorsal region is the imaging feature of SN. SSTR2 expression and LMCD1-AS1:GRM7-AS1 fusion gene event expected to become a new molecular marker for SN. Somatostatin receptor ligand therapy may be a potential therapy for SN.