Morphometric Analysis Research Articles

Morphometric analysis of actin networks.

The organization of cytoskeletal elements is pivotal for coordinating intracellular transport in eukaryotic cells. Several quantitative measures based on image analysis have been proposed to characterize morphometric features of fluorescently labeled actin networks. While helpful in detecting differences in actin organization between treatments or genotypes, the accuracy of these measures could not be rigorously assessed due to a lack of ground-truth data to which they could be compared. To overcome this limitation, we utilized coarse-grained computer simulations of actin filaments and cross-linkers to generate synthetic actin networks with varying levels of bundling. We converted the simulated networks into pseudofluorescence images similar to images obtained using confocal microscopy. Using both published and novel analysis procedures, we extracted a series of morphometric parameters and benchmarked them against analogous measures based on the ground-truth actin configurations. Our analysis revealed a set of parameters that reliably reports on actin network density, orientation, ordering, and bundling. Application of these morphometric parameters to root epidermal cells of Arabidopsis thaliana revealed subtle changes in network organization between wild-type and mutant cells. This work provides robust measures that can be used to quantify features of actin networks and characterize changes in actin organization for different experimental conditions.

Endosomal membrane budding patterns in plants

Multivesicular endosomes (MVEs) sequester membrane proteins destined for degradation within intralumenal vesicles (ILVs), a process mediated by the membrane-remodeling action of Endosomal Sorting Complex Required for Transport (ESCRT) proteins. In Arabidopsis, endosomal membrane constriction and scission are uncoupled, resulting in the formation of extensive concatenated ILV networks and enhancing cargo sequestration efficiency. Here, we used a combination of electron tomography, computer simulations, and mathematical modeling to address the questions of when concatenated ILV networks evolved in plants and what drives their formation. Through morphometric analyses of tomographic reconstructions of endosomes across yeast, algae, and various land plants, we have found that ILV concatenation is widespread within plant species, but only prevalent in seed plants, especially in flowering plants. Multiple budding sites that require the formation of pores in the limiting membrane were only identified in hornworts and seed plants, suggesting that this mechanism has evolved independently in both plant lineages. To identify the conditions under which these multiple budding sites can arise, we used particle-based molecular dynamics simulations and found that changes in ESCRT filament properties, such as filament curvature and membrane binding energy, can generate the membrane shapes observed in multiple budding sites. To understand the relationship between membrane budding activity and ILV network topology, we performed computational simulations and identified a set of membrane remodeling parameters that can recapitulate our tomographic datasets.

A magnetic resonance imaging-based morphometric analysis of bilateral L1-L5 oblique lumbar interbody fusion corridor: feasibility of safe surgical approach and influencing factors.

Retrospective cross-sectional study. To investigate the size and local anatomy of the right and the left-sided oblique corridors between L1-L5 levels and identify the potential impact of increasing age and sex on corridor size. The oblique lumbar interbody fusion (OLIF) was introduced by Silvestre and his colleagues as a solution to the approach-related complications associated with anterior lumbar interbody fusion and lateral lumbar interbody fusion. Limited data were available describing the local anatomy and morphology of this approach. Imaging data of 300 patients (150 males and 150 females) who underwent 1.5T magnetic resonance imaging (MRI) scans of the lumbar spine at Indian Spinal Injuries Centre, New Delhi, India between January 2023 and January 2024 were retrospectively reviewed. The cohort was stratified into six age groups (21-30, 31-40, 41-50, 51-60, 61-70, and >70 years) with 25 patients in each age group for both sexes. T2 weighted axial MRI images were analyzed from the L1-L5 level at the mid-disc level to calculate the corridor size. The local anatomical differences were recorded. At L1-L2, L2-L3, L3-L4, and L4-L5 levels, the mean corridor sizes in males were 17.48, 15.50, 13.41, and 9.32 mm on the left side, and 11.48, 7.12, 4.34, and 1.64 mm on the right side, respectively. The corresponding mean corridor sizes in females were 10.34, 12.94, 12.64, and 7.22 mm on the left side and 2.66, 3.52, 3.69, and 1.64 mm on the right side, respectively. For both sides, the corridor size was significantly affected by sex, increased with age, and decreased at the lower lumbar disc levels. A left-sided OLIF approach is more feasible for both sexes. The right-sided approach is less likely to be performed effectively.

Erosion of the temporal bone by vestibular schwannoma: morphometrics and predictive modeling.

To perform a comprehensive morphometric analysis of vestibular schwannomas (VS) using multimodal imaging, focusing on the relationship between tumor characteristics and internal acoustic canal (IAC) changes. We analyzed a cohort of patients undergoing radiosurgery for VS, utilizing high-definition MRI and bone CT for detailed anatomical assessment. Image co-registration and fusion techniques were employed to examine VS and IAC dimensions. Advanced statistical methods, including logistic regression, were applied to identify patterns of IAC dilation and establish predictive indicators for these morphological changes. The study included 659 patients (51.1% female, mean age 56.37years) with evenly distributed tumor lateralization. Koos grades were I (22.9%), II (29.9%), III (38.2%), IVa (8.9%), and IVb (0.3%). Most tumors (90.9%) extended both inside and outside the IAC. Ipsilateral IAC (IIAC) dimensions were significantly larger than contralateral, with IIAC volume 49% greater (p < .0001). Higher Koos grades correlated with increased intra-canalicular lesion volume (icLV), which was strongly associated with IIAC size. Logistic regression identified icLV as the strongest predictor of IIAC dilation (AUC = 0.7674, threshold = 137.52 mm3). The icLV appears central to the pathophysiological development of VS and its impact on IAC anatomy. While limited by a selective patient base and static imaging data, these findings enhance the understanding of VS-IAC interactions, offering insights for improved clinical management and further research.

TLR4-mediated chronic neuroinflammation has no effect on tangle pathology in a tauopathy mouse model.

Alzheimer's disease (AD) is marked by the accumulation of fibrillary aggregates composed of pathological tau protein. Although neuroinflammation is frequently observed in conjunction with tau pathology, current preclinical evidence does not sufficiently establish a direct causal role in tau tangle formation. This study aimed to evaluate whether chronic Toll-like receptor 4 (TLR4) stimulation, induced by a high dose of lipopolysaccharide (LPS, 5 mg/kg), exacerbates neurofibrillary tangle (NFT) pathology in a transgenic mouse model of tauopathy that expresses human truncated 151-391/3R tau, an early feature of sporadic AD. We utilized a transgenic mouse model of tauopathy subjected to chronic TLR4 stimulation via weekly intraperitoneal injections of LPS over nine consecutive weeks. Neurofibrillary tangle formation, microglial activation, and tau hyperphosphorylation in the brainstem and hippocampus were assessed through immunohistochemistry, immunofluorescence, and detailed morphometric analysis of microglia. Chronic LPS treatment led to a significant increase in the number of Iba-1+ microglia in the LPS-treated group compared to the sham group (p < 0.0001). Notably, there was a 1.5- to 1.7-fold increase in microglia per tangle-bearing neuron in the LPS-treated group. These microglia exhibited a reactive yet exhausted phenotype, characterized by a significant reduction in cell area (p < 0.0001) without significant changes in other morphometric parameters, such as perimeter, circumference, solidity, aspect ratio, or arborization degree. Despite extensive microglial activation, there was no observed reduction in tau hyperphosphorylation or a decrease in tangle formation in the brainstem, where pathology predominantly develops in this model. These findings suggest that chronic TLR4 stimulation in tau-transgenic mice results in significant microglial activation but does not influence tau tangle formation. This underscores the complexity of the relationship between neuroinflammation and tau pathology, indicating that additional mechanisms may be required for neuroinflammation to directly contribute to tau tangle formation.

Identification of erosion-prone watersheds for prioritizing soil and water conservation in a changing climate using morphometric analysis and GIS

Identification of erosion-prone watersheds for prioritizing soil and water conservation in a changing climate using morphometric analysis and GIS

Morphometric analysis of the hard palate in sex estimation among koreans using three-dimensional computed tomography

Accurate sex estimation is crucial for comprehensive analysis of the biological profiles of unidentified human skeletal remains. However, there is a notable lack of research specifically addressing the morphometrics of the hard palate. Therefore, this study aimed to derive discriminant equations using the hard palate and assess their applicability for sexing partial skeletal remains in a contemporary Korean population. Statistical analyses were performed for 24 measurements derived from three-dimensional models of the hard palate, generated using computed tomography scans of 301 individuals (156 males, 145 females). Descriptive statistics revealed significant sexual dimorphism in the mean comparison of hard palate sizes between Korean males and females, with males exhibiting larger palates across all measurements (p < 0.05). Discriminant function score equations were generated to aid in sex determination. Univariate analysis yielded an accuracy range of 57.8–75.1%, whereas the stepwise method achieved an accuracy of 80.7% with five selected variables: IF-PNS, GFL-GFR, IF-GFR, Pr-EcL, and Pr-EnR. The results of this metric analysis demonstrate the usefulness of the hard palate for sex estimation in the contemporary Korean population. These findings have potential implications for forensic investigations, archeological studies, and population-specific anatomical research.

Monitoring Myelin Lipid Composition and the Structure of Myelinated Fibers Reveals a Maturation Delay in CMT1A.

Findings accumulated over time show that neurophysiological, neuropathological, and molecular alterations are present in CMT1A and support the dysmyelinating rather than demyelinating nature of this neuropathy. Moreover, uniform slowing of nerve conduction velocity is already manifest in CMT1A children and does not improve throughout their life. This evidence and our previous studies displaying aberrant myelin composition and structure in adult CMT1A rats prompt us to hypothesize a myelin and axon developmental defect in the CMT1A peripheral nervous system. Peripheral myelination begins during the early stages of development in mammals and, during this process, chemical and structural features of myelinated fibers (MFs) evolve towards a mature phenotype; deficiencies within this self-modulating circuit can cause its blockage. Therefore, to shed light on pathophysiological mechanisms that occur during development, and to investigate the relationship among axonal, myelin, and lipidome deficiencies in CMT1A, we extensively analyzed the evolution of both myelin lipid profile and MF structure in WT and CMT1A rats. Lipidomic analysis revealed a delayed maturation of CMT1A myelin already detectable at P10 characterized by a deprivation of sphingolipid species such as hexosylceramides and long-chain sphingomyelins, whose concentration physiologically increases in WT, and an increase in lipids typical of unspecialized plasma membranes, including phosphatidylcholines and phosphatidylethanolamines. Consistently, advanced morphometric analysis on more than 130,000 MFs revealed a delay in the evolution of CMT1A axon and myelin geometric parameters, appearing concomitantly with lipid impairment. We here demonstrate that, during normal development, MFs undergo a continuous maturation process in both chemical composition and physical structure, but these processes are delayed in CMT1A.

Taxonomy of the Palearctic socially parasitic Temnothorax (Myrmoxenus) ants (Hymenoptera: Formicidae).

The ant genus Temnothorax is one of the most diverse in the Palearctic region, comprising several species with different life histories and uncertain taxonomic backgrounds. Socially parasitic Temnothorax ant species were typically described decades ago, primarily based on traditional morphological traits. In some aspects, these species have come back into the spotlight in recent years, necessitating a comprehensive taxonomic revision of the species of the genus. In this paper, we present a quantitative morphology-based taxonomic revision of the Temnothorax corsicus species group (formerly called Myrmoxenus genus) based on the analysis of 20 continuous morphometric traits collected from 394 worker and 19 traits from 473 gyne individuals belonging to 240 samples. Based on morphometric analyses, we propose junior synonymy for Temnothorax tamarae (Arnol'di, 1968) under T. ravouxi (André, 1896), and T. microcellatus (Soudek, 1925) is revived and is considered a senior synonym of T. menozzii (Finzi, 1924). Detailed descriptions, measurements, distribution, and host usage of all ten species are given. Dichotomous keys to workers, known gynes, and photographs of all species are presented.

Manifestation of polystyrene microplastic accumulation in brain with emphasis on morphometric and histopathological changes in limbic areas of Swiss albino mice

The widespread problem of microplastic (MP) contamination is becoming a major threat to the globe. Although most of the research to date has concentrated on the physiological impacts of MPs exposure, a relatively new field of study is beginning to examine its effects on the behaviour and limbic regions of the brain. In this study, exposure to polystyrene MPs (PS-MPs) for acute and sub-chronic durations negatively affected cognition and induced anxiety-like behaviour in mice. PS-MPs were detected in vital organs of mice, including the brain, which induced neurobehavioural and pathological changes in the limbic system. Furthermore, morphometric analysis revealed a significant decrease in the total cell count in the Dentate Gyrus (DG) and Cornu Ammonis (CA) regions of the hippocampus. Signs of neuronal injury and dystrophic changes were observed in the cortex, amygdala, and hypothalamus, potentially affecting anxiety and fear responses. Our study thus provides insight into the effect of PS-MPs on the neurobiology of the brain’s limbic system and related behavioural alterations.

Morphometric Tomographic Analysis of the Head of the Tridactyl Humanoid Specimen from Nasca-Peru

Objective: To report the tomographic and morphometric analysis of the head of the tridactyl humanoid specimen from Nazca, Peru. Method: A qualitative case study approach. RadiAnt DICOM Viewer software version 4.2.1 was used to analyze lengths, diameters, and volume in tomographic images of the head. The morphological biometric analysis applied anthropometric methods using some craniometric points and cephalometric angles. Results and Discussion: As a result, it is reported that there are atypical, strange, and exceptional morphometric imaging features in the cephalic segment of specimen M01. The cephalometric analysis based on the ANB angle revealed a class II skeletal pattern, and according to the Bjorl-Jarabak analysis, it has a convex facial profile with hypodivergent growth (brachyfacial). The patient also has maxillary biprotrusion, severe protrusion of upper and lower incisors, loss of teeth, presence of root remnants, severe dental abrasion, non-assessable canine class, absence of three third molars and ocular protrusion. Based on craniometric points, the SNA angle (Sella, Nasion and Point A) and the SNB angle (Sella, Nasion and Point B) maxillary protrusion and mandibular protrusion were diagnosed. Implications of the research: It is concluded that the combination of uncommon morpho-anatomical features in the maxillofacial and cranial massif do not correspond to a human craniofacial biotype, but could be considered as suggestive findings of morpho-anatomical features typical of a hominid species similar to humans. Originality/Value: The expansion of biometric and morphoanatomical data of the head reinforces the hypothesis that morphologically it would be a non-human hybrid species.

A computed tomography–based morphometric analysis of thoracic pedicles in a European population

PurposeThe goal of this retrospective study was to perform a CT imaging assessment of thoracic pedicles to provide a representative understanding of pedicle morphology for pedicle-based fixation systems commonly used in orthopedics, trauma and neurosurgery. This study aimed to better understand the morphology of the spine and give spine surgeons a better understanding of thoracic spine anatomy.MethodsIn this study, we retrospectively measured the thoracic spine pedicles of a total of 16 males and 16 females, totaling in 768 individual pedicles. For the measurements, we used standardized planes in computed tomography imaging with a maximum slice thickness of 1 mm.ResultsIn brief, we identified significant differences in various measurements of male and female pedicle morphology. The medial cortical wall of the pedicles was significantly thicker than the lateral wall, and, in both sexes, the thoracic vertebral body number four was the vertebra with the least amount of cortical bone in the pedicle.ConclusionsSurgeons performing operations involving pedicle screw placement should be aware of the sex-specific differences in thoracic spine pedicle morphology noted in this research.

Renal protective potential of pentoxifylline, chlorpromazine, and lovastatin in ischemia-reperfusion injury: An experimental study.

This study aimed to evaluate the ability of pentoxifylline when compared to lovastatin and chlorpromazine as nephroprotective substances in cases of renal ischemia and reperfusion syndrome (IRI). A total of 36 adult male animals were randomly allocated into four groups (untreated control group, pentoxifylline group, lovastatin group, and chlorpromazine group), each consisting of nine animals. All groups were submitted to experimental ischemia and reperfusion procedures. The animals were evaluated 24, 72 and 120 hours after IRI, including physical examinations, serum urea and creatinine measurements, as well as histopathological, morphometric, and stereological analyses of the renal tissue. Results indicated that 24 hours after IRI, only chlorpromazine was effective in controlling azotemia. At the 72-hour mark, both chlorpromazine and pentoxifylline exhibited efficacy. After 120 hours, all three substances demonstrated renal protective qualities. Pentoxifylline was the most effective in preserving the structural integrity of kidney tissue, followed by chlorpromazine. In conclusion, all three treatments (pentoxifylline, chlorpromazine, and lovastatin) were effective. Pentoxifylline proved to be promising in the response against acute tubular necrosis, although chlorpromazine presented earlier renoprotective effects in terms of maintaining renal function.

Floral morphology and pollen placement strategies of bat-pollinated flowers: a comparative analysis within a guild of chiropterophilous plants in a neotropical dry forest

BackgroundSynchronopatric plant species, coexisting and flowering simultaneously, often engage in intense competition for pollen deposition on shared pollinators. This study focuses on the intricate dynamics of chiropterophilous flowers within the neotropical bat-pollination plant guild, specifically investigating the mechanical fit of reproductive structures to pollinating bats at the community level.MethodsUtilizing a diverse guild of bat-pollinated plant species from the Caatinga, the largest dry forest in the Neotropics, our research integrates various key components. Initially, we identified specific contact sites for floral reproductive structures on the bat's body, exploring diverse pollen placement strategies. Subsequent efforts involved characterizing floral traits within the guild and examining their associations with different pollen placement strategies. Precision in the contact of floral reproductive structures was estimated, and findings were integrated by associating pollen placement strategies and precision with the investment in pollen production.ResultsWe found that certain bat body parts, particularly the face and neck, were more frequently contacted by reproductive structures. The three identified categories of pollen placement strategies were evenly distributed among plant species, each linked to specific floral traits. Notably, the absence of oriented herkogamy prevailed in 70% of the species. Morphometric analyses unveiled significant variations in operative distances among species, emphasizing exceptional variability in certain outliers. While precision in pollen transfer was influenced by key factors, surprisingly, investment in pollen production did not differ among plants with distinct pollen placement strategies. Furthermore, it showed no correlation with fundamental accuracy.ConclusionsThe subsequent exploration delves into the intricate associations between distinct floral characteristics and various pollen placement strategies, shaping the complex pollen landscape on bat bodies. This research provides valuable insights into the community-level dynamics of chiropterophilous flowers in the Caatinga Dry Forest, emphasizing the role of different pollen deposition strategies in facilitating the coexistence of multiple plant species within the chiropterophilous guild.

Integrated Morphometric and Hypsometric Analysis of Niragantipalli Micro Watershed Using Remote Sensing and Geographical Information System Techniques

Employing Remote sensing (RS) and geographic information system (GIS) for the morphometric parameters analysis are discovered to be tremendous usefulness in the prioritization of watersheds for soil, water conservation and natural resource management at micro watershed level. The analysis of morphometric parameters plays a crucial role for understanding and managing watersheds. In current study an, attempt was to determine the morphological parameters of Niragantipalli micro-watershed in Chikkaballapura District of Karnataka, India. For detail study, Google earth pro, GPS visualizer conversion toll and Arc GIS were used for preparation of DEM and delineation of the watershed boundary. GIS was used for evaluation of basic, linear, areal and relief aspects of morphometric parameters. The Niragantipalli micro-watershed occupies an area of 632 ha with third order stream (truck order) and dendritic drainage pattern. The mean bifurcation ratio of the micro-watershed is 2.5 it suggests that the drainage system formed on homogeneous rock when the influences of geologic structures on the network of streams were negligible and generate sharp peak flow. With a drainage density of 1.31 km/km2, the drainage network is extremely coarse. The watershed is elongated, as shown by the form factor of 0.27 and elongation ratio of 0.58. The results from the morphometric analysis of the watershed are very beneficial for developing and designing conservation structures of soil and watershed management measures. The hypsometric curves’ structure as well as estimated hypsometric integral results reflects the Niragantipalli Micro Watershed erosional stages. As a result, the study concludes that morphometric and hypsometric analysis findings may be useful to stakeholders participating in catchment development and management projects.

Computer-assisted morphometric analysis of the relationship between the coronoid and condylar processes of the mandible

: The mandible is the most durable and only movable bone that constitutes the lower one-third of the face.The mandibular condyle and coronoid processes are two anatomical structures located in the superior portion of the ramus of the mandible. Morphometric understanding of these structures is key to the diagnosis of various disorders associated with the temporomandibular region. It also aids in devising a plan for the management of such disorders.: The purpose of this study is to evaluate the anatomical corelation between the condyle and coronoid of the mandible.: This retrospective study was conducted by obtaining 100 high-resolution computed tomography images from departmental archived records between 2018 and 2024. After acquisition, these images were incorporated into MIMICS Materialize software to create stereolithography models, and morphometric analysis was carried out. Out of 100 HRCT data obtained, 87 were male and 13 were female. There is a statistically significant difference in length and angulation of the coronoid and condyle on both sides. The condyle length for males was (4 ± 5.5 mm) higher than the condyle length of females on both sides. However, the coronoid length of males and females varies in a range of 0.5-2mm on both sides of the mandible. Understanding the morphological variation of mandibular condylar and coronoid processes aids in various fields of medicine like forensics, anthropology, and reconstructive maxillofacial surgery. Our study inference will aid surgeons in planning coronoid grafts for condylar reconstruction as well as other maxillofacial reconstructions. Additionally, it helps in forensic odontology to determine a person's age and gender.

Morphometric trait normalization, cluster analysis and molecular phylogenetic analysis in delimiting sympatric Neolissochilus hexastichus and N. hexagonolepis in Umngi River, Meghalaya (India)

Aim: To assess the ability of an integrative approach comprising multivariate morphometric data analysis and mitochondrial cytochrome oxidase subunit I (CO I) sequence divergence analysis in delimiting sympatric Neolissochilus hexastichus (McClleland, 1839) and N. hexagonolepis (McClleland, 1839) mahseer populations in River Umngi, Meghalaya. Methodology: Authoritative descriptions of mahseers were referred during the sampling of 40 individuals from River Umngi, Meghalaya. Multivariate morphometric data were normalized with respect to standard length. The normalization procedure maintained the particular shape factor for each sample. Normalised data were subjected to hierarchical clustering on principal components Analysis (HCPC) for grouping samples according to morphometric features. Genetic affinities based on CO I sequence divergence were assessed by Bayesian Inference (BI) and Automatic Barcode Gap Discovery (ABGD) protocols. Results: The normalization protocols removed the variations in traits due to body size effects and facilitated the identification of allometric traits. HCPC analysis revealed morphometric features that had a significant impact on clustering. Nine N. hexagonolepis and 13 N. hexastichus individuals were identified by integrative morphological and molecular phylogenetic approach. The remaining 18 individuals had incongruence in their memberships in the morphometric and phylogenetic clusters. Interpretation: The integrative approach, apart from delineating N. hexagonolepis and N. hexastichus congeners, highlighted the need to include nuclear genetic markers in future studies for confirming the presence of natural hybrids in sympatric populations of Neolissochilus mahseers. Key words: Cluster, Morphometric, Neolissochilus, Normalization, Phylogenetics

Emc1 is essential for vision and zebrafish photoreceptor outer segment morphogenesis.

Inherited retinal diseases (IRDs) are a rare group of eye disorders characterized by progressive dysfunction and degeneration of retinal cells. In this study, we characterized the raifteirí (raf) zebrafish, a novel model of inherited blindness, identified through an unbiased ENU mutagenesis screen. A mutation in the largest subunit of the endoplasmic reticulum membrane protein complex, emc1 was subsequently identified as the causative raf mutation. We sought to elucidate the cellular and molecular phenotypes in the emc1-/- knockout model and explore the association of emc1 with retinal degeneration. Visual behavior and retinal electrophysiology assays demonstrated that emc1-/- mutants had severe visual impairments. Retinal histology and morphometric analysis revealed extensive abnormalities, including thinning of the photoreceptor layer, in addition to large gaps surrounding the lens. Notably, photoreceptor outer segments were drastically smaller, outer segment protein expression was altered and hyaloid vasculature development was disrupted. Transcriptomic profiling identified cone and rod-specific phototransduction genes significantly downregulated by loss of emc1. These data shed light on why emc1 is a causative gene in inherited retinal disease and how outer segment morphogenesis is regulated.

Accessory Ligament of the Deep Digital Flexor Tendon of the Horse Forelimb and Its Relationship with the Superficial Digital Flexor Tendon: A Plastination, Histological, and Morphometry Study.

The accessory ligament of the deep digital flexor tendon (AL-DDFT) plays a crucial role in the stay apparatus of the horse. This study aimed to investigate the anatomical relationship between the AL-DDFT, the superficial digital flexor tendon (SDFT), and other structures in the metacarpal region. Sixteen distal forelimbs from eight horses, aged 1 to 6 years, were evaluated through macroscopic, microscopic, and morphometric analyses, utilizing detailed dissection, E12 plastinated sections, and histological analysis. During lateral dissection, a connection was observed between the AL-DDFT and the SDFT. Histological evaluation revealed that this connection was a fibrous band (FB), extending the common synovial sheath (CSS) to the SDFT, along with associated collagen fibrils of the epiligament and peritenon. Additionally, two distinct forms of the AL-DDFT were identified, Type I and Type II, with Type II showing a greater cross-sectional area (CSA) than Type I. While numerous morphological and morphometric studies have explored the AL-DDFT and related structures, research incorporating plastination-based morphological and histological evaluations remains scarce. The findings provide valuable insights for both the morphological and clinical assessment of structures within the metacarpal region.

Long COVID in Immunocompromised and Immunocompetent Patients: A Clinical, Morphologic, and Virologic Portrait.

Coronavirus disease 2019 (COVID) primarily affects the lung and can lead to chronic/post-COVID syndrome. Some insights about late pulmonary changes occurring in patients recovering from COVID have been published, but the evidence of detailed pathologic changes coming from follow-up care patients with long COVID is limited. To evaluate tissue morphologic and viral features in transbronchial biopsies of long COVID patients (immunocompetent and immunocompromised). This retrospective observational study included 18 patients (9 immunocompetent and 9 immunocompromised) who were consecutively referred to outpatient clinic for post-COVID pneumonia, undergoing transbronchial biopsy. Several histologic changes were analyzed by computer-assisted morphometric analysis. As organizing pneumonia (OP) was consistently detected, fibrosis and inflammation were also evaluated in transbronchial biopsies from 28 control patients with histologic confirmation of OP. Tissue SARS-CoV-2 and the subgenomic transcripts were investigated. Morphologic findings were correlated with clinical and radiologic data. Long COVID patients showed lower inflammation than controls (P < .001) despite a similar fibrotic extension. When considering separately the 2 long COVID groups, the same inflammatory infiltrate extension was found, whereas a higher fibrotic remodeling characterized the immunocompetent subgroup (P = .05). Molecular investigation showed that SARS-CoV-2 was present in tissue samples obtained from 3 long COVID patients. Long COVID patients showed a peculiar OP pattern, with more vascular and fibrotic changes. SARS-CoV-2 RNA, even in replicative status, can be detected in lung biopsies of both immunocompetent and immunocompromised patients. This pilot study is a forerunner of more in-depth lung tissue investigations to gain a better understanding of long COVID pathobiology.