Anatomical Similarities Research Articles

Thoracic ultrasound for diagnosing pneumopathies in neotropical primates

Lung ultrasound can be useful for the early diagnosis and treatment of respiratory complications. The combination of air and soft tissue confirms imaging artefacts that can contribute to differentiation between healthy and deteriorated lung tissue. Although non-human primates are often chosen as research models due to their anatomical and physiological similarity to humans, there is a lack of data on the use of lung ultrasound in these individuals. The aim of this study was to evaluate the contribution of ultrasound examinations of the thoracic region of Callithrix sp. for diagnosing pneumopathy. Parameters were obtained from 166 new world non-human primates of both sexes, aged between 1 and 15 years and weighing between 128 g and 680 g kept under human care at the Mucky Project in Itu, São Paulo. Thoracic ultrasound examinations were carried out using a LOGIQe—R7 device (GE, United States), with a 10–22 MHz linear transducer, at four points on the left and right antimeres. Among these 166 individuals, 72 had some kind of pulmonary alteration. Forty-one of the animals with pulmonary alterations diagnosed on ultrasound died and underwent necropsy. Histopathological examination showed that in half of the samples the lung tissue was compatible with some form of pneumopathy. Considering these cases, the pulmonary alterations diagnosed through thoracic ultrasound examination in Callithrix sp. can be correlated with the occurrence of pneumopathy, which is often asymptomatic. Lung ultrasound is an important tool for use in clinics to detect and monitor respiratory diseases and can save lives by enabling early treatment.

Structural MRI of brain similarity networks.

Recent advances in structural MRI analytics now allow the network organization of individual brains to be comprehensively mapped through the use of the biologically principled metric of anatomical similarity. In this Review, we offer an overview of the measurement and meaning of structural MRI similarity, especially in relation to two key assumptions that often underlie its interpretation: (i) that MRI similarity can be representative of architectonic similarity between cortical areas and (ii) that similar areas are more likely to be axonally connected, as predicted by the homophily principle. We first introduce the historical roots and technical foundations of MRI similarity analysis and compare it with the distinct MRI techniques of structural covariance and tractography analysis. We contextualize this empirical work with two generative models of homophilic networks: an economic model of cost-constrained connectional homophily and a heterochronic model of ontogenetically phased cortical maturation. We then review (i) studies of the genetic and transcriptional architecture of MRI similarity in population-averaged and disorder-specific contexts and (ii) developmental studies of normative cohorts and clinical studies of neurodevelopmental and neurodegenerative disorders. Finally, we prioritize knowledge gaps that must be addressed to consolidate structural MRI similarity as an accessible, valid marker of the architecture and connectivity of an individual brain network.

Characterization of A Bronchoscopically Induced Transgenic Lung Cancer Pig Model for Human Translatability.

There remains a need for animal models with human translatability in lung cancer (LC) research. Findings in pigs have high impact on humans due to similar anatomy and physiology. We present the characterization of a bronchoscopically-induced LC model in Oncopigs carrying inducible KRAS G12D and TP53 R167H mutations. Twelve Oncopigs underwent 29 injections via flexible bronchoscopy. Eighteen Adenovirus-Cre recombinase gene (AdCre) inductions were performed endobronchially (n=6) and transbronchially with a needle (n=12). Eleven control injections were performed without AdCre. Oncopigs underwent serial contrast-enhanced chest CT with clinical follow-up for 29 weeks. Following autopsy, lung and organ tissues underwent histopathology, immunohistochemistry, and RNA-sequencing with comparative analysis with The Cancer Genome Atlas (TCGA) human LC data. All 18 sites of AdCre injections had lung consolidations on CT imaging. Transbronchial injections led to histopathologic invasive cancer and/or carcinoma in situ (CIS) in 11/12 (91.7%), and invasive cancer (excluding CIS) in 8/12 (66.6%). Endobronchial inductions led to invasive cancer in 3/6 (50%). A soft tissue metastasis was observed in one Oncopig. Immunohistochemistry confirmed expression of Pan-CK+/epithelial cancer cells, with macrophages and T cells infiltration in the tumor microenvironment. Transcriptome comparison showed 54.3% overlap with human LC (TCGA), in contrast to 29.88% overlap of KRAS-mutant mouse LC with human LC. The transgenic and immunocompetent Oncopig model has a high rate of LC following bronchoscopic transbronchial induction. Overlap of the Oncopig LC transcriptome with human LC transcriptome was noted. This pig model is expected to have high clinical translatability to the human LC patient.

Dynamic Narrowing of the Diaphragmatic Vena Cava in Ovis aries.

Dorset sheep (Ovis aries) are common models in translational cardiovascular research due to physiologic and anatomic similarities to humans. While employing ovine subjects to study single-ventricle physiology, we repeatedly observed position-based changes in central venous pressure (CVP) which could not be explained by hydrostatic (gravitational) effects. Inferior vena cava (IVC) narrowing or compression has been demonstrated in numerous species, and we hypothesised that this phenomenon might explain our observations in O. aries. This study aimed to characterise position-dependent morphology of the IVC in O. aries using catheter-based hemodynamic and dimensional measurements, three-dimensional MRI reconstruction and histological analysis. Baseline measurements revealed a significant reduction in IVC dimensions at the level of the diaphragm (dVC) compared to the abdominal vena cava (aVC) and thoracic vena cava (tVC). We also observed a transdiaphragmatic pressure gradient along the IVC, with higher pressures in the aVC compared to the tVC. We found that variation of position and fluid status altered IVC haemodynamics. Histological data showed variable muscularity along the length of the IVC, with greater smooth muscle content in the aVC than the tVC. These findings will improve understanding of baseline ovine physiology, help refine experimental protocols and facilitate the translation of findings to the clinic.

Wood Anatomical and Demographic Similarities Between Self-Standing Liana and Tree Seedlings in Tropical Dry Forests of Colombia.

Canopy lianas differ considerably from trees in terms of wood anatomical structure, and they are suggested to have a demographic advantage-faster growth and higher survival-than trees. However, it remains unclear whether these anatomical and demographic differences persist at the seedling stage, when most liana species are self-standing and, consequently, might be ecologically similar to trees. We assessed how self-standing liana and tree seedlings differ in relation to wood anatomy, growth, and survival. We measured 12 wood traits and monitored seedling growth and survival over one year for 10 self-supporting liana and 10 tree seedling species from three tropical dry forests in Colombia. Liana and tree seedlings exhibited similar survival rates and wood anatomies for traits related to water storage and mechanical support. Yet, for traits associated with water transport, liana seedlings showed greater variability in vessel lumen size, while tree seedlings had higher vessel density. Also, the liana relative growth rate was significantly higher than for trees. These results indicate that, while self-supporting liana and tree seedlings are anatomically similar in terms of mechanical support and water storage-likely contributing to their similar survival rates-liana seedlings have a growth advantage, possibly due to more efficient water transport. These findings suggest that the well-documented anatomical and demographic differences between adult lianas and trees may depend on the liana's developmental stage, with more efficient water transport emerging as a key trait from early stages.

A novel Non-rodent animal model of hydrochloric acid-induced acute and chronic lung injury

Hydrochloric acid is one of the most prevalent and hazardous chemicals. Accidental spills occur in industrial plants or during transportation. Exposure to HCl can induce severe health impairment, including acute and chronic pulmonary diseases. We have previously described the molecular, structural, and functional aspects of the development of chronic lung injury and pulmonary fibrosis caused by intratracheal instillation of HCl in mice. Although mouse models of human disease have many advantages, rodents are evolutionary far from human and exhibit significant anatomical and physiological differences. Genetic and anatomic similarities between rabbits and humans are significantly higher. Rabbit models of HCl-induced lung injury have been used sparsely to evaluate acute lung injury. In this study, for the first time, we utilized rabbits as a model of HCl-induced pulmonary fibrosis and chronic lung injury. We present molecular, histological, and functional evidence that demonstrate the utility of using this model for studying new pharmaceutics against pulmonary fibrosis.

Feasibility and early outcomes of atrial septal defect prostheses use for percutaneous closure of widely open patent foramen ovale

Abstract Background The efficient closure of patent foramen ovale (PFO) with short canal length and large width, usually associated with atrial septal aneurysm (ASA), remains challenging. These cases frequently require the use of larger PFO devices to avoid the risk of device embolism at the cost of a higher rate of residual shunting, mostly due to interdisk spacing. The use of atrial septal defect (ASD) prosthesis could be useful in these patients. Purpose To describe feasibility and early outcomes of the use of ASD device for percutaneous closure of widely open PFO representing an "ASD-like anatomy". Methods Since January 2022 in a high volume French university center, we started to use ASD device for percutaneous closure of selected cases of PFO with complex anatomy as mainly defined by a sheathed width of PFO ≥ 5 mm and sheathed canal length ≤ 10 mm (Figure 1) facing major per-operative residual shunt with PFO prostheses in some patients. In addition to the descriptive results, we compared this ASD device subgroup with a cohort of patients with similar anatomy but previously treated in our center with PFO device. All available transesophageal echocardiography (TEE) examinations were reviewed. The main objective was to describe the feasibility of the procedure (success and safety), the secondary endpoint was immediate post-procedural moderate to severe residual right-to-left shunt (RLS), defined as ≥ 10 bubbles in the left atrium within 3 cardiac cycles after transfemoral agitated saline injection. Results A total of 65 patients was treated with ASD devices, procedural success was achieved in all patients with a low rate (4,2%) of intrahospital complications (two supraventricular arrythmia, one anaphylactic shock and one minor laryngeal injury) and without device embolism. As compared with a cohort of 127 patients of similar anatomy treated with PFO device, patients in the ASD device group had more complex characteristics especially higher mean sheathed PFO width and shorter mean sheathed PFO canal length. Immediate post-procedural residual moderate to severe RLS did not differ significatively between groups (Table 1). No or minimal shunting was observed in 91% and 92% of cases (p=NS) but the three patients with severe RLS were all in the PFO device group. Conclusion Percutaneous closure of "ASD-like" PFO with ASD prostheses is feasible and safe. Larger studies and longer follow-ups are now required to confirm the expected improved sealing effect with this strategy.

The Use of Primates as Experimental Models in Scientific Research and its Ethical Implications

Non-human primates (NHPs) are considered ideal experimental models for replicating human diseases, due to their physiological, anatomical and neurological similarities to humans. However, the use of NHPs in research has ethical considerations and requires significant financial and temporal investments, due to the costs involved in the process and evaluation time. In addition to ethical issues and legal protection, research with experimental primate models involves advantages, such as the extreme physiological similarity, and disadvantages, such as the difficulty in establishing parameters for pain management and assessment. This literature review analyzed articles from the Pubmed, Scopus and Web of Science databases published in the last five years. This review included 12 articles that addressed topics such as scientific research, primate therapies, animal welfare and legal protection, highlighting the relevance of NHPs in scientific studies and interest in using these models to understand human diseases in order to develop new therapies. Despite the ethical challenges involved in this issue, it was discussed that it is important to take into account the scientific benefits and ethical considerations, as well as developing alternative methods to reduce the use of primates in research.

The post-cranial anatomy and functional morphology of Conoryctes comma (Mammalia: Taeniodonta) from the Paleocene of North America.

Conoryctes comma is a member of the enigmatic group Taeniodonta, Paleogene mammals that have been found only in North America. Taeniodonts were part of the first wave of placental mammal diversification after the end-Cretaceous extinction. The lack of postcranial elements has limited the understanding of the anatomy and locomotion of Conoryctes, and how it compared to other taeniodonts. We here describe the postcranial anatomy and functional morphology of Conoryctes, based largely on nine new specimens found in the San Juan Basin, New Mexico, USA. The specimens include elements of the axial column, such as the axis, sacrum, and ribs; the humerus, ulna, radius, and part of the manus; the innominate, femur, tibia, and part of the pes, including the tarsals. Conoryctes was a medium-sized mammal, with a robust humerus, radius, and femur, and with anatomical similarities to other conoryctid taeniodonts and Onychodectes. The tarsal elements of Conoryctes show characteristics of the "leptictimorph astragalocalcaneal morphology" as seen in other Paleogene mammals, such as Escavadodon, Palaeanodon, and Procerberus. Anatomical features of the forelimb and hindlimb of Conoryctes indicate that it was a scratch-digging animal with powerful forearm muscles and well-stabilized digits, features that may have helped it adapt to the subtropical forests of the San Juan Basin, approximately 63 million years ago. This corroborates the previous hypothesis that digging adaptations are seen in all members of Taeniodonta for which the postcranial elements are known, and that digging ability was present in the common ancestor of the clade and potentially central to their radiation after the environmental destruction of the end-Cretaceous extinction.

Exploring dual energy CT synthesis in CBCT-based adaptive radiotherapy and proton therapy: application of denoising diffusion probabilistic models

Background.Adaptive radiotherapy (ART) requires precise tissue characterization to optimize treatment plans and enhance the efficacy of radiation delivery while minimizing exposure to organs at risk. Traditional imaging techniques such as cone beam computed tomography (CBCT) used in ART settings often lack the resolution and detail necessary for accurate dosimetry, especially in proton therapy.Purpose.This study aims to enhance ART by introducing an innovative approach that synthesizes dual-energy computed tomography (DECT) images from CBCT scans using a novel 3D conditional denoising diffusion probabilistic model (DDPM) multi-decoder. This method seeks to improve dose calculations in ART planning, enhancing tissue characterization.Methods.We utilized a paired CBCT-DECT dataset from 54 head and neck cancer patients to train and validate our DDPM model. The model employs a multi-decoder Swin-UNET architecture that synthesizes high-resolution DECT images by progressively reducing noise and artifacts in CBCT scans through a controlled diffusion process.Results.The proposed method demonstrated superior performance in synthesizing DECT images (High DECT MAE 39.582 ± 0.855 and Low DECT MAE 48.540± 1.833) with significantly enhanced signal-to-noise ratio and reduced artifacts compared to traditional GAN-based methods. It showed marked improvements in tissue characterization and anatomical structure similarity, critical for precise proton and radiation therapy planning.Conclusions.This research has opened a new avenue in CBCT-CT synthesis for ART/APT by generating DECT images using an enhanced DDPM approach. The demonstrated similarity between the synthesized DECT images and ground truth images suggests that these synthetic volumes can be used for accurate dose calculations, leading to better adaptation in treatment planning.

Perspective on using non-human primates in Exposome research

The physiological and pathological changes in the human body caused by environmental pressures are collectively referred to as the Exposome. Human society is facing escalating environmental pollution, leading to a rising prevalence of associated diseases, including respiratory diseases, cardiovascular diseases, neurological disorders, reproductive development disorders, among others. Vulnerable populations to the pathogenic effects of environmental pollution include those in the prenatal, infancy, and elderly stages of life. Conducting Exposome mechanistic research and proposing effective health interventions are urgent in addressing the current severe environmental pollution. In this review, we address the core issues and bottlenecks faced by current Exposome research, specifically focusing on the most toxic ultrafine nanoparticles. We summarize multiple research models being used in Exposome research. Especially, we discuss the limitations of rodent animal models in mimicking human physiopathological phenotypes, and prospect advantages and necessity of non-human primates in Exposome research based on their evolutionary relatedness, anatomical and physiological similarities to human. Finally, we declare the initiation of NHPE (Non-Human Primate Exposome) project for conducting Exposome research using non-human primates and provide insights into its feasibility and key areas of focus. SynopsisNon-human primate models hold unique advantages in human Exposome research.

Translational Relevance and Future Integration of the Oncopig Cancer Model in Preclinical Applications.

Porcine cancer models offer a valuable platform for evaluating interventions such as devices, surgeries, and locoregional therapies, which are often challenging to test in mouse models. In addition to size and anatomical similarities with humans, pigs share greater similarities in genetics, immunity, drug metabolism, and metabolic rate with humans as compared to mouse models, increasing their translational relevance. This review focuses on the Oncopig Cancer Model, a genetically engineered porcine model designed to recapitulate human cancer. Harboring a transgenic cassette that expresses oncogenic mutant KRAS and TP53 under control of a Cre-Lox system, the Oncopig allows temporal and spatial control of tumor induction. Its versatility has enabled the development of diverse cancer models including liver, pancreatic, lung, and bladder cancer. Serving as a clinically relevant model for human cancer, the Oncopig addresses unmet clinical needs and holds immense promise for advancing preclinical cancer research and therapeutic development.

Zebrafish as a Model for Multiple Sclerosis.

Background: Zebrafish have become a key model organism in neuroscience research because of their unique advantages. Their genetic, anatomical, and physiological similarities to humans, coupled with their rapid development and transparent embryos, make them an excellent tool for investigating various aspects of neurobiology. They have specifically emerged as a valuable and versatile model organism in biomedical research, including the study of neurological disorders such as multiple sclerosis. Multiple sclerosis is a chronic autoimmune disease known to cause damage to the myelin sheath that protects the nerves in the brain and spinal cord. Objective: This review emphasizes the importance of continued research in both in vitro and in vivo models to advance our understanding of MS and develop effective treatments, ultimately improving the quality of life for those affected by this debilitating disease. Conclusions: Recent studies show the significance of zebrafish as a model organism for investigating demyelination and remyelination processes, providing new insights into MS pathology and potential therapies.

A pilot study examining periodontally healthy middle-aged humans and monkeys display different levels of alveolar bone resorption, gingival inflammatory infiltrate, and salivary microbiota profile.

Monkeys are an appropriate model for periodontal research owing to their similar dental anatomy and physiology unlike humans. Extensive literature exists on pathological periodontitis in monkeys and humans, although concerns regarding whether healthy middle-aged monkeys and humans display the same periodontal and oral microbial status remains unclear. The current study aimed to compare alveolar bone resorption, gingival inflammatory infiltrate, and salivary microbiota profile in periodontally healthy middle-aged humans and monkeys. CBCT examination and histological analysis were performed to compare the periodontal status in middle-aged healthy humans and monkeys. Oral saliva16S rRNA sequencing was performed to analyze the oral microbial profile. The alveolar resorption was compared between humans and monkeys, to determine the periodontal health. The percentage attachment of attachment loss was more around the posteriors teeth in humans when compared to monkeys (p<0.05). The degree of gingival inflammation was analyzed in both the groups, the expression of CD 34,45was higher in humans. 16S rRNA analysis demonstrated less diversity of salivary microorganisms in humans than in monkeys. The relative abundance of Aggregatibacter, Haemophilus, Gemella, and Porphyromonas at the genus level was significantly less in humans than in monkeys (p(<0.05). The periodontally healthy middle-aged humans and monkeys display different alveolar bone resorption and gingival inflammatory infiltrate levels. Furthermore, the salivary microbiota profile showed distinctly different oral microbiomes in these two primates. Our results suggest that the difference in alveolar bone status and gingival inflammatory infiltrate in healthy humans and monkeys might be associated with the diversity of the oral microbiome.

Current Scenario and Future Perspectives of Porcine Corneal Xenotransplantation.

Corneal diseases represent a significant cause of blindness worldwide, with corneal transplantation being an effective treatment to prevent vision loss. Despite substantial advances in transplantation techniques, the demand for donor corneas exceeds the available supply, particularly in developing countries. Cornea xenotransplantation has emerged as a promising strategy to address the worldwide scarcity, notably using porcine corneas. In addition to the inherent immune privilege of the cornea, the low cost of porcine breeding and the anatomical and physiological similarities between humans and pigs have made porcine corneas a viable alternative. Nonetheless, ethical concerns, specifically the risk of xenozoonotic transmission and the necessity for stringent biosafety measures, remain significant obstacles. Moreover, the success of xenotransplantation is compromised by innate and adaptive immune responses, which requires meticulous consideration and further studies. Despite these challenges, recent breakthroughs have further contributed to reducing immunogenicity while preserving the corneal architecture. Advances in genetic engineering, such as the use of CRISPR-Cas9 to eliminate critical porcine antigens, have shown promise for mitigating immune reactions. Additionally, new immunosuppressive protocols, such as have techniques like decellularization and the use of porcine-derived acellular matrices, have greatly increased graft survival in preclinical models. Future research must focus on refining immunomodulatory strategies and improving graft preparation techniques to ensure the long-term survival and safety of porcine corneal xenotransplantation in clinical trials in humans.

Multi-Omics Atlas-Assisted Discovery of Transcription Factors for Selective T Cell State Programming.

Transcription factors (TFs) regulate the differentiation of T cells into diverse states with distinct functionalities. To precisely program desired T cell states in viral infections and cancers, we generated a comprehensive transcriptional and epigenetic atlas of nine CD8 + T cell differentiation states for TF activity prediction. Our analysis catalogued TF activity fingerprints of each state, uncovering new regulatory mechanisms that govern selective cell state differentiation. Leveraging this platform, we focused on two critical T cell states in tumor and virus control: terminally exhausted T cells (TEX term ), which are dysfunctional, and tissue-resident memory T cells (T RM ), which are protective. Despite their functional differences, these states share significant transcriptional and anatomical similarities, making it both challenging and essential to engineer T cells that avoid TEX term differentiation while preserving beneficial T RM characteristics. Through in vivo CRISPR screening combined with single-cell RNA sequencing (Perturb-seq), we validated the specific TFs driving the TEX term state and confirmed the accuracy of TF specificity predictions. Importantly, we discovered novel TEX term -specific TFs such as ZSCAN20, JDP2, and ZFP324. The deletion of these TEX term -specific TFs in T cells enhanced tumor control and synergized with immune checkpoint blockade. Additionally, this study identified multi-state TFs like HIC1 and GFI1, which are vital for both TEX term and T RM states. Furthermore, our global TF community analysis and Perturb-seq experiments revealed how TFs differentially regulate key processes in T RM and TEX term cells, uncovering new biological pathways like protein catabolism that are specifically linked to TEX term differentiation. In summary, our platform systematically identifies TF programs across diverse T cell states, facilitating the engineering of specific T cell states to improve tumor control and providing insights into the cellular mechanisms underlying their functional disparities.

On the function and origin of the avian renal portal shunt and its potential significance throughout evolution.

All birds possess a unique venous architecture surrounding the kidneys known as the renal portal system. In veterinary medicine, this system is well known for causing a first-pass effect when medication is administered parenterally via the leg veins, that is venous blood from the leg is filtered before entering general circulation, thus possibly compromising adequate dosage. Additionally, bilateral valves are present in these veins, and it has been hypothesized that they play a crucial role in regulating flow through the kidneys to protect them against increases in blood pressure. While this hypothesis has been acknowledged, it has not been thoroughly explored. We propose that the function of the renal portal valve extends beyond its significance for kidney function, potentially impacting general hemodynamics. Examining anatomical similarities with extant non-avian reptiles, which lack the renal portal shunt with valve, could reveal additional functionalities of this system in birds. Given the endothermic metabolism and the energetically expensive locomotor activity of birds, the resistance of the hepatic and renal portal system might constrain the blood flow from splanchnic to non-splanchnic blood vessels necessary for (sustained) peak performance. Therefore, diverting blood from the renal portal system using the renal portal valve as a regulatory structure might represent a key adaptation to facilitate sustained peak performance. In addition, we hypothesize that this shunt and valve represents a very early adaptation in amniotes, possibly lost in extant non-avian reptiles but enhanced in birds, with a pivotal role in maintaining hemodynamic homeostasis to support the high metabolic rates characteristic of birds.

Dual knowledge‐guided two‐stage model for precise small organ segmentation in abdominal CT images

AbstractMulti‐organ segmentation from abdominal CT scans is crucial for various medical examinations and diagnoses. Despite the remarkable achievements of existing deep‐learning‐based methods, accurately segmenting small organs remains challenging due to their small size and low contrast. This article introduces a novel knowledge‐guided cascaded framework that utilizes two types of knowledge—image intrinsic (anatomy) and clinical expertise (radiology)—to improve the segmentation accuracy of small abdominal organs. Specifically, based on the anatomical similarities in abdominal CT scans, the approach employs entropy‐based registration techniques to map high‐quality segmentation results onto inaccurate results from the first stage, thereby guiding precise localization of small organs. Additionally, inspired by the practice of annotating images from multiple perspectives by radiologists, novel Multi‐View Fusion Convolution (MVFC) operator is developed, which can extract and adaptively fuse features from various directions of CT images to refine segmentation of small organs effectively. Simultaneously, the MVFC operator offers a seamless alternative to conventional convolutions within diverse model architectures. Extensive experiments on the Abdominal Multi‐Organ Segmentation (AMOS) dataset demonstrate the superiority of the method, setting a new benchmark in the segmentation of small organs.

Reduced diffusional limitations in carnation stems facilitate higher photosynthetic rates and reduced photorespiratory losses compared with leaves.

Green stem photosynthesis has been shown to be relatively inefficient but can occasionally contribute significantly to the carbon budget of desert plants. Although the possession of green photosynthetic stems is a common trait, little is known about their photosynthetic characteristics in non-desert species. Dianthus caryophyllus is a semi-woody species with prominent green stems, which show similar photosynthetic anatomy with leaves. In the present study, we used a combination of gas exchange and chlorophyll fluorescence measurements, some of which were taken under varying O2 and CO2 partial pressures, to investigate whether the apparent anatomical similarities between the species' leaves and stems translate into similar photosynthetic physiology and capacity for CO2 assimilation. Both organs displayed high photosynthetic electron transport rates (ETR) and similar values of steady-state non-photochemical quenching (NPQ), albeit leaves could attain them faster. The analysis of OJIP transients showed that the quantum efficiencies and energy fluxes along the photosynthetic electron transport chain are largely similar between leaves and stems. Stems displayed higher total conductance to CO2 diffusion, similar biochemical properties, significantly higher photosynthetic rates and lower water use efficiency than leaves. Leaf ETR was more sensitive to sub-ambient O2 and super-ambient CO2 partial pressures, while leaves also displayed a higher relative rate of Rubisco oxygenation. We conclude that the highly responsive NPQ and the enhanced photorespiration and WUE in leaves represent photoprotective and water-conserving adaptations to the high incident light intensities they experience naturally, at the expense of higher CO2 assimilation rates, which the vertically orientated stems can readily attain.

Correlation between meibomian gland dysfunction and sebaceous adenitis in dogs.

Sebaceous adenitis (SA) is an immune-mediated disease targeting the sebaceous glands. Meibomian gland dysfunction is a disease affecting meibomian glands with inflammatory features. Sebaceous and meibomian glands share anatomical, physiological and embryological similarities. The involvement of meibomian glands in dogs with SA is currently unknown. To evaluate meibomian glands in dogs affected by SA and compare them with healthy dogs. Eighteen dogs were enrolled. Nine dogs with SA were retrospectively identified from clinical records and represented the case group. Nine healthy, breed- and age-matched dogs were prospectively enrolled in the control group. Both groups underwent dermatological examination, Schirmer tear test-1 (STT-1), tear meniscus height (TMH), slit-lamp biomicroscopy, interferometry (INT) and noncontact infrared meibography (NIM). One third of SA dogs presented subepithelial crystalline opacities. No significant difference between groups was observed in TMH (p = 0.944) and STT-1 values (p = 0.066). INT (p = 0.016) and NIM grades (p = 0.010) were significantly higher and lower in the SA group compared to the control group, respectively. INT values decreased with age (η = 0.930), while NIM scores (η = 0.935) increased. Clinical Relevance: Subepithelial crystalline opacities in SA dogs might reflect a reduced tear film quality. In the absence of standardised methods, INT and NIM proved to be noninvasive and useful methods to examine meibomian glands. Dogs with SA showed a thinner lacrimal lipid layer and more severe meibomian gland abnormalities than control dogs, which seemed to progress with age.