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Background: It is well recognized that the molar activity of a radioligand is an important pharmacokinetic parameter, especially in positron emission tomography (PET) of small animals. Occupation of a significant number of binding sites by radioligand molecules results in low radioligand accumulation in a target region (mass effect). Nevertheless, small-animal PET studies have often been performed without consideration of the molar activity or molar dose of radioligands. A simulation study would therefore help to assess the importance of the mass effect in small-animal PET. Here, we introduce a new compartmental model-based numerical method, which runs on commonly used spreadsheet software, to simulate the effect of molar activity or molar dose on the pharmacokinetics of radioligands. Results: Assuming a two-tissue compartmental model, time-concentration curves of a radioligand were generated using four simulation methods and the well-known Runge–Kutta numerical method. The values were compared with theoretical values obtained under an ultra-high molar activity condition (pseudo-first-order binding kinetics), a steady-state condition and an equilibrium condition (second-order binding kinetics). For all conditions, the simulation method using the simplest calculation yielded values closest to the theoretical values and comparable with those obtained using the Runge–Kutta method. To satisfy a maximum occupancy less than 5%, simulations showed that a molar activity greater than 150 GBq/μmol is required for a model radioligand when 20 MBq is administered to a 250 g rat and when the concentration of binding sites in target regions is greater than 1.25 nM. Conclusions: The simulation method used in this study is based on a very simple calculation and runs on widely used spreadsheet software. Therefore, simulation of radioligand pharmacokinetics using this method can be performed on a personal computer and help to assess the importance of the mass effect in small-animal PET. This simulation method also enables the generation of a model time-activity curve for the evaluation of kinetic analysis methods. [ABSTRACT FROM AUTHOR]

Treating complex posterior cerebral artery (PCA) aneurysms, such as fusiform, giant, and dissecting aneurysms, poses significant challenges. Parent artery occlusion carries a risk of ischemic stroke and fails to alleviate mass effects. This study aims to analyze the technical nuances and patient outcomes of treating complex PCA aneurysms, ranging from the P1 to P2P segments, using a Zygomatic Anterolateral Temporal Approach(ZATA) combined with flow reconstruction. This study was a retrospective study. Surgical treatment was performed on twelve patients with complex PCA aneurysms located in the P1 to P2P segments. Ten patients underwent flow reconstruction including Superficial Temporal Artery(STA)-Middle Cerebral Artery(MCA),Internal Maxillary Artery(IMA)—Radial Artery(RA)—MCA,STA-PCA(P2), and IMA-RA-PCA(P2). The aneurysm occlusion rate, surgical complications, and patient prognosis, including stroke occurrence/ modified Rankin Scale(mRS), were recorded and analyzed. Using the ZATA, all twelve complex PCA aneurysms were successfully clipped/resected/trapped. This included two high-position aneurysms (> 3 mm above the posterior clinoid process) at the P1/P2 junction and three P2P aneurysms. The mass effects of six large or giant aneurysms were resolved or alleviated. Postoperative and follow-up CTA/DSA confirmed the patency of the bypass vessels. Four patients experienced strokes in the perioperative period, with three ischemic and one hemorrhagic. The median follow-up period was 28.5 months. At the last follow-up, the good prognosis rate (mRS ≤ 2) was 83.3%, and one patient had died. Clipping/resection/trapping of aneurysms via the ZATA, combined with flow reconstruction, is a feasible option for treating complex PCA aneurysms from the P1 to P2P segments. This approach helps maintain or improve cerebral perfusion in the affected vascular territory. [ABSTRACT FROM AUTHOR]

Abstract Background It is well recognized that the molar activity of a radioligand is an important pharmacokinetic parameter, especially in positron emission tomography (PET) of small animals. Occupation of a significant number of binding sites by radioligand molecules results in low radioligand accumulation in a target region (mass effect). Nevertheless, small-animal PET studies have often been performed without consideration of the molar activity or molar dose of radioligands. A simulation study would therefore help to assess the importance of the mass effect in small-animal PET. Here, we introduce a new compartmental model-based numerical method, which runs on commonly used spreadsheet software, to simulate the effect of molar activity or molar dose on the pharmacokinetics of radioligands. Results Assuming a two-tissue compartmental model, time-concentration curves of a radioligand were generated using four simulation methods and the well-known Runge–Kutta numerical method. The values were compared with theoretical values obtained under an ultra-high molar activity condition (pseudo-first-order binding kinetics), a steady-state condition and an equilibrium condition (second-order binding kinetics). For all conditions, the simulation method using the simplest calculation yielded values closest to the theoretical values and comparable with those obtained using the Runge–Kutta method. To satisfy a maximum occupancy less than 5%, simulations showed that a molar activity greater than 150 GBq/μmol is required for a model radioligand when 20 MBq is administered to a 250 g rat and when the concentration of binding sites in target regions is greater than 1.25 nM. Conclusions The simulation method used in this study is based on a very simple calculation and runs on widely used spreadsheet software. Therefore, simulation of radioligand pharmacokinetics using this method can be performed on a personal computer and help to assess the importance of the mass effect in small-animal PET. This simulation method also enables the generation of a model time-activity curve for the evaluation of kinetic analysis methods.

Intracerebral hemorrhage (ICH) is a critical neurological disease caused by the rupture of blood vessels within the brain parenchyma, with high mortality and morbidity rates. Currently, much research has focused on the injury mechanisms and intervention strategies following ICH, yet clinically effective treatments that significantly improve patient outcomes remain scarce. The mass effect refers to the mechanical compression of brain tissue by the hematoma during ICH, and its crucial role in neural function damage has been widely recognized in clinical practice. Therefore, exploring the mechanisms and pathways of the mass effect mediating primary and secondary injuries after ICH holds significant practical importance for the development of clinical intervention strategies. This article reviews the injury mechanisms and pathways of the mass effect during the onset and progression of ICH, aiming to provide references and theoretical bases for intervention research following ICH. [ABSTRACT FROM AUTHOR]

Seagrass recovery has been reported across the globe where previously eutrophied waters have become less nutrient‐rich. In the European Wadden Sea, different recovery trajectories were found after riverine nutrient loads decreased, namely full, temporary and no recovery. We compiled intertidal seagrass presence (Zostera noltei and Z. marina) and eutrophication data for 1930–2020, to relate the seagrass trajectories and regional eutrophication differences to riverine nutrient loads, and inferred prospects for seagrass recovery.Seagrass fully recovered in the less eutrophic North Frisian region. The recovery trajectory was tightly coupled to riverine nutrient load reduction. Relative seagrass area (meadow area/region area) dropped from 10% prior to eutrophication to 2% during the eutrophication peak, increased to 7% during the nutrient reduction period and subsequently expanded to 13%. Colonization of marginal habitats was observed, indicating propagule spillover from neighbouring meadows.The more eutrophic southern regions showed no or only temporary seagrass recovery. Prospects for (limited) recovery are good in only two out of four southern regions, provided that riverine nutrient loads are further reduced by ~40% (reference: 2010–2017). Without this reduction, seagrasses may only temporarily recover and will remain vulnerable to erratic disturbances like macroalgae accumulation or storms.Historical evidence and application of habitat suitability models suggest that the potential relative seagrass area in the southern regions is low: less than 0.2% in the western Dutch region and maximum 2.4% in the Ems‐Jade region.Synthesis and applications. Within a large seascape (15,000 km2) the least eutrophicated region showed seagrass recovery upon nutrient reduction. We translated the critical riverine nutrient loads for this recovery, via regional eutrophication indicators, to loads that may enable a sustained recovery in the other regions. This technique is applicable in other complex systems, provided sufficient historical data are available. Propagule spillover exerts a positive feedback at metapopulation scale leading to acceleration of recovery. Occupied and potential seagrass habitat (e.g. assessed by the maximum recorded area in the past) are thus important landscape selection criteria for restoration, particularly when eutrophication is not yet sufficiently reduced. [ABSTRACT FROM AUTHOR]

Oncocytoma arising from the parotid gland and extending into the parapharyngeal space (PPS) has not been previously reported. A 64-year-old woman presented with a large slowly growing mass extending from the parotid to the submandibular area, expanding medially to displace the pharynx across the midline. Core-needle biopsy revealed an oncocytoma in the PPS measuring 120 × 88 × 60 mm in size. Although the tumor was of an unprecedentedly large size and extended into multiple spaces, it could be removed via a cervical–parotid approach without osteotomy. The resected tumor was again diagnosed as oncocytoma. A postoperative complication was weakness of the ipsilateral facial nerve, which almost completely resolved in 6 months. No recurrence has been noted on 1 y follow-up. We were able to resect an extremely large oncocytoma arising from the parotid gland without osteotomy. [ABSTRACT FROM AUTHOR]

Background: Intracranial space is divided into three compartments by the falx cerebri and tentorium cerebelli. We assessed whether cerebrospinal fluid (CSF) distribution evaluated by a specifically developed deep-learning neural network (DLNN) could assist in quantifying mass effect. Methods: Head trauma CT scans from a high-volume emergency department between 2018 and 2020 were retrospectively analyzed. Manual segmentations of intracranial compartments and CSF served as the ground truth to develop a DLNN model to automate the segmentation process. Dice Similarity Coefficient (DSC) was used to evaluate the segmentation performance. Supratentorial CSF Ratio was calculated by dividing the volume of CSF on the side with reduced CSF reserve by the volume of CSF on the opposite side. Results: Two hundred and seventy-four patients (mean age, 61 years ± 18.6) after traumatic brain injury (TBI) who had an emergency head CT scan were included. The average DSC for training and validation datasets were respectively: 0.782 and 0.765. Lower DSC were observed in the segmentation of CSF, respectively 0.589, 0.615, and 0.572 for the right supratentorial, left supratentorial, and infratentorial CSF regions in the training dataset, and slightly lower values in the validation dataset, respectively 0.567, 0.574, and 0.556. Twenty-two patients (8%) had midline shift exceeding 5 mm, and 24 (8.8%) presented with high/mixed density lesion exceeding >25 ml. Fifty-five patients (20.1%) exhibited mass effect requiring neurosurgical treatment. They had lower supratentorial CSF volume and lower Supratentorial CSF Ratio (both p < 0.001). A Supratentorial CSF Ratio below 60% had a sensitivity of 74.5% and specificity of 87.7% (AUC 0.88, 95%CI 0.82-0.94) in identifying patients that require neurosurgical treatment for mass effect. On the other hand, patients with CSF constituting 10-20% of the intracranial space, with 80-90% of CSF specifically in the supratentorial compartment, and whose Supratentorial CSF Ratio exceeded 80% had minimal risk. Conclusion: CSF distribution may be presented as quantifiable ratios that help to predict surgery in patients after TBI. Automated segmentation of intracranial compartments using the DLNN model demonstrates a potential of artificial intelligence in quantifying mass effect. Further validation of the described method is necessary to confirm its efficacy in triaging patients and identifying those who require neurosurgical treatment. [ABSTRACT FROM AUTHOR]

Dispersal is more intense in the ocean than on land because most marine taxa present planktonic life stages that are transported by currents even without specific morphological traits. Thus, species dispersal shapes the distribution of biodiversity along seascapes and drives the composition of biodiversity assemblages. To identify marine assembling zones which characterise spatial areas particularly prone to receive and retain similar animal assemblages from the regional pool of species through passive dispersal, we propose a community‐based approach grounded on Lagrangian simulations of plankton dispersal. This novel approach was applied to communities (coast, outer shelf, slope, seamounts and islands; 0–80 m depth) of the Tropical Southwestern Atlantic and used to assess connectivity pathways. For that, we classified the modelled particles in 15 categories according to biological traits (planktonic life duration and spawning habitat) of representative planktonic communities. From the hierarchical clustering of the multivariate matrix containing the amount of arriving particles from each category in each cell we defined 14 assembling zones. Results highlighted that the assembling zones were mostly shaped by the degree of exposure to currents and the presence of mesoscale features (eddies, recirculation) derived from the interaction between these currents and coastlines. The boundaries, dispersal and connectivity patterns of these zones consistently align with local and regional in situ spatial distribution and abundance patterns of organisms, and provide an appropriate basis for the formulation of ecological hypotheses in the metacommunity framework to be tested in situ, such as the balance between species sorting and mass effect assembling archetypes. This approach, when coupled with the knowledge of other processes shaping communities' structure and distribution, provides important insights for regions and animal groups for which knowledge is limited or absent, and more generally allows for a comprehensive overview of the distribution of distinct communities and connectivity pathways along marine environments. [ABSTRACT FROM AUTHOR]

Abstract: Aim Our goal was to relate the phytoplankton metacommunity to its possible determinants in a micro watershed: (I) determinants related to landscape-scale filtering, (II) determinants referring to local microhabitat filtering, (III) determinants referring to previous colonization, and (IV) determinants representing three different dispersal routes. Methods Eight sampling stations were selected along the Cascavel River watershed, located in the state of Paraná, Brazil. Samples were collected quarterly for three years. All phytoplankton samples were quantitatively analyzed to determine the density of the metacommunity. In addition, it was characterized the landscape in terms of land use and occupation, and environmental characterization in terms of physical and chemical variables of the water. All data underwent relevant statistical analysis, where variance partitioning was carried out using partial RDA models, with prior selection of predictor variables, to estimate the relative role of each predictor in the community. We also compared three possible dispersal routes: “Asymmetric Eigenvector Map” (AEM), “Overland” and “Watercourse”. Results It was found that the metacommunity was best explained by “asymmetric eigenvector mapping” (AEM), indicating that because it is a small spatial scale the high connectivity between the sampling stations enables species to disperse overland as well. The different filters act together and depend on rainfall variation. Besides fluctuating temporally, the influence of these mechanisms is subject to which dispersal hypothesis is being considered. Conclusions At the watershed scale, we argue that small-scale processes should be considered, since they homogenize the landscape and consequently leave the environmental gradient similar between sampling stations. In addition, the connectivity of colonization patches is essential to understand the behavior of microalgae that have a high dispersal capacity and are not restricted only to the river course.

BackgroundIntracranial space is divided into three compartments by the falx cerebri and tentorium cerebelli. We assessed whether cerebrospinal fluid (CSF) distribution evaluated by a specifically developed deep-learning neural network (DLNN) could assist in quantifying mass effect.MethodsHead trauma CT scans from a high-volume emergency department between 2018 and 2020 were retrospectively analyzed. Manual segmentations of intracranial compartments and CSF served as the ground truth to develop a DLNN model to automate the segmentation process. Dice Similarity Coefficient (DSC) was used to evaluate the segmentation performance. Supratentorial CSF Ratio was calculated by dividing the volume of CSF on the side with reduced CSF reserve by the volume of CSF on the opposite side.ResultsTwo hundred and seventy-four patients (mean age, 61 years ± 18.6) after traumatic brain injury (TBI) who had an emergency head CT scan were included. The average DSC for training and validation datasets were respectively: 0.782 and 0.765. Lower DSC were observed in the segmentation of CSF, respectively 0.589, 0.615, and 0.572 for the right supratentorial, left supratentorial, and infratentorial CSF regions in the training dataset, and slightly lower values in the validation dataset, respectively 0.567, 0.574, and 0.556. Twenty-two patients (8%) had midline shift exceeding 5 mm, and 24 (8.8%) presented with high/mixed density lesion exceeding >25 ml. Fifty-five patients (20.1%) exhibited mass effect requiring neurosurgical treatment. They had lower supratentorial CSF volume and lower Supratentorial CSF Ratio (both p

The mass effect associated with large or giant intracranial aneurysms is difficult for traditional endovascular treatment. This study investigated whether flow diverters can relieve the aneurysmal mass effect caused by aneurysmal compression symptoms. Fifty-five patients with unruptured large and giant intracranial aneurysms treated by a flow diverter at our institution from January 2014 to February 2022 were retrospectively evaluated. In this study, 53 patients were included. Initially, 27 patients (51.9%), including 10 with compressive optic neuropathy, 12 with third nerve palsy, 2 with facial hyperesthesia, and 11 with sixth nerve palsy, were symptomatic. The symptom duration was shorter in the improved group (n = 2.2 ± 4.0 vs. n = 3.1 ± 3.9, P = 0.49). Thrombus formation following the flow diversion procedure was typically observed on magnetic resonance imaging (MRI) performed immediately and was not significantly associated with symptomatic improvement (OR = 0.395; 95% CI (0.058–2.698), P = 0.343). However, symptomatic improvement was seen in most patients when the aneurysm size decreased on MRI. A reduction in the aneurysm size on the MRI at the 3-month follow-up was correlated with symptomatic improvement in the multivariate analysis (OR = 0.08, 95% CI (0.013–0.485), P < 0.05). A flow diverter might help alleviate compression symptoms caused by large or giant intracranial aneurysms. Shrinkage of the aneurysm within 3 months postoperatively and a shorter duration of symptoms contribute to the favorable outcomes of mass effect. Ultimately, prompt treatment is crucial for improving symptomatic intracranial artery aneurysms. [ABSTRACT FROM AUTHOR]

An 84-year-old male with previously documented poor medical follow-up presented with progressive painless proptosis of the right eye. Right upper eyelid ptosis, limited motility, proptosis, and inferomedial displacement of the right globe were noted on the exam. Computed tomography (CT) imaging revealed a right retrobulbar extraconal heterogenous mass with ill-defined borders. Biopsy revealed a malignant adenocarcinoma with tumor markers suggestive of a colorectal primary. A rectal mass was identified during a systemic workup. After biopsy, the patient was diagnosed with stage IV metastatic rectal adenocarcinoma. He began palliative radiation therapy shortly following diagnosis.

Dispersal is a main determinant of community assembly. Landscape configurations of rivers, lakes, or ponds are often independently considered in this framework. However, these systems share species conforming to a waterscape with different environments coupled by dispersal. While empirical results support a main role of this coupling on biodiversity organization, it is difficult to assess its importance at large geographic scales. Using a theoretical approach, we quantified the potential role of dispersal through different freshwater ecosystems of the United Kingdom and Ireland on biogeographic diversity patterns. We implemented a coalescent model considering 11,131 communities connected by distance-dependent dispersal and with species that have different performances for recruitment in three different aquatic habitats. Biogeographic diversity patterns were estimated for each habitat alone or for the whole waterscape combining ephemeral, temporal, and permanent waters. The results indicated that the coupling between different types of environments fostered local diversity, in a magnitude that increased from the ephemeral to permanent waters and from poorer to richer communities. Furthermore, a strong spatial structure in the potential effect of dispersal among different freshwater environments was observed, indicating that freshwater biogeography was likely determined by the connection among freshwater ecosystems to a larger extent than previously thought. [ABSTRACT FROM AUTHOR]

Background and Objectives: Giant bullae rupture easily and cause tension pneumothorax, which can cause problems during general anesthesia. However, the hemodynamic instability that can occur due to the mass effect of an unruptured giant bulla should not be overlooked. Case report: A 43-year-old male patient visited the emergency room with an abdominal wound. There was a giant emphysematous bulla in the left lung. Emergency surgery was decided upon because there was active bleeding according to abdominal CT. After tracheal intubation, the patient's blood pressure and pulse rate dramatically decreased. His blood pressure did not recover despite the use of vasopressors and discontinuation of positive pressure ventilation applied to the lungs. Thus, a bullectomy was immediately performed. The patient's blood pressure and pulse rate were normalized after the bullectomy. Conclusions: If emergency surgery under general anesthesia is required in a patient with a giant emphysematous bulla, it is safe to minimize positive pressure ventilation and remove the giant emphysematous bulla as soon as possible before proceeding with the remainder of the surgery. Tension pneumothorax due to the rupturing of a bulla should be considered first. However, hemodynamic changes might occur due to the mass effect caused by a giant bulla. [ABSTRACT FROM AUTHOR]

Introduction: Splanchnic arterial aneurysms are a rare but potentially lethal disease with a mortality rate of more than 10% after rupture. Endovascular therapy is the first-line treatment for splanchnic aneurysms. However, appropriate management for splanchnic aneurysms after failed endovascular therapy remained inconclusive. Materials and methods: A retrospective review was performed for consecutive patients (from 2019 to 2022) who underwent salvage surgeries for splanchnic artery aneurysms following failed endovascular therapy. The authors defined failed endovascular therapy as the technical infeasibility to apply endovascular therapy, the incomplete exclusion of the aneurysm, or the incomplete resolution of preoperative aneurysm-associated complications. Salvage operations included aneurysmectomy with vascular reconstruction and partial aneurysmectomy with directly closing of bleeders from the intraluminal space of the aneurysms. Results: Seventy-three patients received endovascular therapies for splanchnic aneurysms, and 13 failed endovascular trials. The authors performed salvage surgeries for five patients and enrolled them in this study, including four false aneurysms of the celiac or superior mesenteric arteries and a true aneurysm of the common hepatic artery. The causes of failed endovascular therapy included coil migration, insufficient space for safely deploying the covered stent, a persistent mass effect from the postembolized aneurysm, or infeasibility for catheter cannulation. The mean hospital stay was nine days (mean ± SD, 8.8 ± 1.6 days), with no one suffering 90-day surgical morbidity and mortality, and all patients getting symptoms improvement. During the follow-up period (mean ± SD, 24 ± 10 months), one patient suffered a small residual asymptomatic celiac artery aneurysm (8 mm in diameter) and was treated conservatively due to underlying liver cirrhosis. Conclusion: Surgical management is a feasible, effective, and safe alternative for splanchnic aneurysms after failed endovascular therapy. [ABSTRACT FROM AUTHOR]

Testicular torsion is a commonly encountered medical emergency in children. A 10-year-old boy with diagnostically confirmed leukemia presented with new onset testis swelling. Scrotal ultrasound showed absent blood flow on the left, consistent with acute testicular torsion. The patient underwent left orchiectomy due to the testis being unsalvageable. Later pathology confirmed lymphoblastic infiltrates. A malignancy of the testicles is rarely associated with torsion and, in the setting of leukemia, suggests widespread disease. Due to the risk of scrotal violation, an inguinal approach is preferable for surgical exploration of the testicles in patients with a history of leukemia.

Background: Magnetic resonance imaging (MRI) is not routinely ordered following spinal fusion. Some literature suggests MRIs are unhelpful due to postoperative changes that obscure interpretation. We aim to describe findings of acute postoperative MRI following anterior cervical discectomy and fusion (ACDF). Methods: The authors retrospectively analyzed adult MRIs completed within 30 days of ACDF (from 2005–2022). T1 and T2 signal intensity in the interbody space dorsal to the graft, mass effect on the dura/spinal cord, intrinsic spinal cord T2 signal, and interpretability were reviewed. Results: In 38 patients there were 58 ACDF levels (1, 2, and 3 levels; 23, 10, and 5, respectively). MRIs were completed on mean postoperative day 8.37 (range; 0–30 days). T1-weighted imaging was described as isointense, hyperintense, heterogenous, and hypointense in 48 (82.8%), 5 (8.6%), 3 (5.2%), and 2 levels (3.4%), respectively. T2-weighted imaging was described as hyperintense, heterogenous, isointense, and hypointense in 41 (70.7%), 12 (20.7%), 3 (5.2%), and 2 levels (3.4%), respectively. There was no mass effect in 27 levels (46.6%), 14 (24.1%) had thecal sac compression, and 17 (29.3%) had cord compression. Conclusions: The majority of MRIs exhibited readily compression and intrinsic spinal cord signal even with various types of fusion constructs. Early MRI after lumbar surgery can be difficult to interpret. However, our results support the use of early MRI to investigate neurological complaints following ACDF. Our findings do not support the idea that epidural blood products and mass effect on the cord are seen in most postoperative MRIs after ACDF.

In the present report, we have described the case of a significantly delayed presentation of a pseudoaneurysm (PSA) and subsequent mass effect causing an acute deep vein thrombosis (DVT). The patient had presented with a mass in the right groin and edema of the right lower extremity prompting further imaging studies. The imaging studies demonstrated a superficial femoral artery PSA and an acute femoral vein DVT. Our patient had no history of recent trauma or femoral access procedures performed in the last ≥5 years. Surgical repair of the PSA was performed, and the DVT was managed with anticoagulation therapy.

Ewing's sarcoma/peripheral primitive neuroectodermal tumor (ES/pPNET) belongs to the family of malignant small and blue round cell tumors. It usually occurs in children and young adults with 3/4th of the cases arising from bone and 1/4 from soft tissue. Here, we present two cases of intracranial ES/pPNET who presented with mass effect. Management consists of surgical excision followed by adjuvant chemotherapy. Intracranial ES/pPNETs are highly aggressive and rare malignancies, reported to comprise of 0.03% of all intracranial tumors. The most common genetic aberration associated with ES/pPNET is chromosomal translocation t (11,12) (q24;q12). Patients with intracranial ES/pPNETs may present in acute or delayed manner. The presenting symptoms and signs depend on the location of the tumor. Intracranial pPNET although slow growing, they are highly vascular and may present as neurosurgical emergencies due to mass effect. We have presented the acute presentation of this tumor and its management. [ABSTRACT FROM AUTHOR]

Background and Objectives: Giant bullae rupture easily and cause tension pneumothorax, which can cause problems during general anesthesia. However, the hemodynamic instability that can occur due to the mass effect of an unruptured giant bulla should not be overlooked. Case report: A 43-year-old male patient visited the emergency room with an abdominal wound. There was a giant emphysematous bulla in the left lung. Emergency surgery was decided upon because there was active bleeding according to abdominal CT. After tracheal intubation, the patient’s blood pressure and pulse rate dramatically decreased. His blood pressure did not recover despite the use of vasopressors and discontinuation of positive pressure ventilation applied to the lungs. Thus, a bullectomy was immediately performed. The patient’s blood pressure and pulse rate were normalized after the bullectomy. Conclusions: If emergency surgery under general anesthesia is required in a patient with a giant emphysematous bulla, it is safe to minimize positive pressure ventilation and remove the giant emphysematous bulla as soon as possible before proceeding with the remainder of the surgery. Tension pneumothorax due to the rupturing of a bulla should be considered first. However, hemodynamic changes might occur due to the mass effect caused by a giant bulla.

Compared to the secondary brain injury after intracerebral haemorrhage (ICH), fewer reports focused on the mechanism of primary brain injury induced by mass effect. Here, the tandem mass tag (TMT) labeling proteomics method was used to study the mechanical damage of the mass effect after ICH. A total of 5390 proteins were identified, and 4593 proteins were quantified, included 80 up-regulated proteins (M/N Ratio > 1.2) and 30 down-regulated proteins (M/N Ratio > 1.2). Bioinformatics and enrichment analysis showed that the differentially expressed proteins were mainly involved in immune response, signal transmission, and oxidative phosphorylation. The mass effect affects the synthesis and metabolism of ATP by mechanically stretching and squeezing the brain tissue. Furthermore, the cell morphology and dendritic development of neurons were also significantly influenced by mass effect, which also cause neuronal damage through the formation of oxidative stress and oxygen-glucose deprivation, and activate the neuronal protection and defense mechanisms. Our results provide the relevant channels and key proteins of primary brain injury caused by mass effect after ICH, which offer a scientific basis for the understanding of ICH injury.

Abstract Background Many pancreatic pseudocysts spontaneously resolve, but larger or symptomatic pseudocysts may require procedural management. Though endoscopic ultrasound guided approaches are standard of care and have high success rates, complications can include bleeding, infection, and splenic perforation. This patient case report details an unusual series of complications of endoscopic cystogastrostomy that should encourage clinicians to evaluate for anatomic disruptions caused by mass effects of pancreatic pseudocysts prior to endoscopic pseudocyst drainage. Case presentation A 53-year-old African American male with a past medical history notable for alcohol use disorder, chronic pancreatitis, and insulin dependent diabetes presented with a 4-day history of left upper quadrant abdominal pain. Computed tomography imaging with contrast revealed enlargement of a known pancreatic pseudocyst to 15.9 × 10.4 cm. Due to pseudocyst size and the patient’s symptoms, endoscopic cystogastrostomy stent placement was performed. However, postprocedurally, he developed leukocytosis to 19,800 cells/m3 (from 14,100 cells/m3 preoperatively) as well as acute hypoxemic respiratory failure with a large left pleural effusion. Postprocedural computed tomography with contrast demonstrated a new large subcapsular splenic hematoma in communication with a new subdiaphragmatic fluid collection. Due to suspicion of endoscopic procedural complication, he underwent open laparotomy which revealed grade 4 splenic laceration, septic splenic hematoma, and a subdiaphragmatic abscess. Conclusions While endoscopic drainage of pancreatic pseudocyst was technically successful, this case demonstrates complications from mass effect of a large pancreatic pseudocyst which putatively tore the splenorenal ligament, leading to excessive separation of the left kidney and spleen. If anatomic disruptions caused by mass effect from a pancreatic pseudocyst are recognized through preprocedural abdominal imaging, such cases may be considered for early open repair versus cystogastrostomy.

The paper offers a reading of Mass Effect: Andromeda (BioWare, 2017) vis-à-vis lost world romance (also dubbed “lost race romance”, or “imperial romance”), a late-Victorian era novelistic genre originating from H. Rider Haggard’s King Solomon’s Mines and serving as a major tool for British Empire propaganda and a source of early science-fiction conventions. We claim that the narrative failure of this ill-received game stems from its adherence to the rigid principles and forceful themes of the genre and the colonial and imperial imaginary informing it. Our analysis aims at highlighting the way 19th-century novelistic convention can be remediated as contemporary digital games, and to expose the link between the imperial imaginary and the ways in which open-world digital games are structured, on both the narrative and gameplay levels, even when they do not directly refer to the historical colonial legacy.

Abstract Elevation is involved in determining plant diversity in montane ecosystems. This study examined whether the distribution of plants in the Yatsugatake Mountains, central Japan, substantiated hypotheses associated with an elevational diversity gradient. Species richness of trees, shrubs, herbs, ferns, and bryophytes was investigated in study plots established at 200‐m elevational intervals from 1,800 to 2,800 m. The changes in plant diversity (alpha and beta diversities, plant functional types, and elevational ranges) with elevation were analyzed in relation to climatic factors and elevational diversity gradient hypotheses, that is, mass effect, mid‐domain effect, and Rapoport's elevational rule. In addition, the elevational patterns of dominance of plant functional types were also analyzed. A comparison of alpha and beta diversities revealed that different plant groups responded variably to elevation; the alpha diversity of trees and ferns decreased, that of herbs increased, whereas the alpha diversity of shrubs and bryophytes showed a U‐shaped relationship and a hump‐shaped pattern. The beta diversity of shrubs, herbs, and bryophytes increased above the subalpine–alpine ecotone. In accordance with these changes, the dominance of evergreen shrubs and graminoids increased above this ecotone, whereas that of evergreen trees and liverworts decreased. None of the plant groups showed a wide elevational range at higher elevations. These elevational patterns of plant groups were explained by climatic factors, and not by elevational diversity gradient hypotheses. Of note, the changes in the dominance of plant groups with elevation can be attributed to plant–plant interactions via competition for light and the changes in physical habitat. These interactions could alter the elevational diversity gradient shaped by climatic factors.

In near-natural basins, zooplankton are key hubs for maintaining aquatic food webs and organic matter cycles. However, the spatial patterns and drivers of zooplankton in streams are poorly understood. This study registered 165 species of zooplankton from 147 sampling sites (Protozoa, Rotifers, Cladocera and Copepods), integrating multiple dimensions (i.e., taxonomic, functional, and phylogenetic) and components (i.e., total, turnover, and nestedness) of α and β diversity. This study aims to reveal spatial patterns, mechanisms, correlations, and relative contribution of abiotic factors (i.e., local environment, geo-climatic, land use, and spatial factors) through spatial interpolation (ordinary kriging), mantel test, and variance partitioning analysis (VPA). The study found that α diversity is concentrated in the north, while β diversity is more in the west, which may be affected by typical habitat, hydrological dynamics and underlying mechanisms. Taxonomic and phylogenetic β diversity is dominated by turnover, and metacommunity heterogeneity is the result of substitution of species and phylogeny along environmental spatial gradients. Taxonomic and phylogenetic β diversity were strongly correlated (r from 0.91 to 0.95), mainly explained by historical/spatial isolation processes, community composition, generation time, and reproductive characteristics, and this correlation provides surrogate information for freshwater conservation priorities. In addition, spatial factors affect functional and phylogenetic α diversity (26%, 28%), and environmental filtering and spatial processes combine to drive taxonomic α diversity (10%) and phylogenetic β diversity (11%). Studies suggest that spatial factors are key to controlling the community structure of zooplankton assemblages in near-natural streams, and that the relative role of local environments may depend on the dispersal capacity of species. In terms of diversity conservation, sites with high variation in uniqueness should be protected (i) with a focus on the western part of the thousand islands lake catchment and (ii) increasing effective dispersal between communities to facilitate genetic and food chain transmission. [Display omitted] • Unravelling the relative roles of abiotic factors on zooplankton α and β diversity. • Phylogenetic and taxonomic β diversity are highly correlated. • Spatial factors strongly affect phylogenetic and functional α diversity. • Environmental filtering and spatial processes co-drive phylogenetic β diversity. • Zooplankton diversity protection should focus on the western TIL catchment. [ABSTRACT FROM AUTHOR]

Ophthalmic artery (OA) is a potential origin of aneurysms. We present a patient with a giant OA aneurysm, with a sudden onset of psychomotor agitation at the admission. Digital subtraction angiography showed an aneurysm originating from the ophthalmic segment of the left internal carotid artery of irregular shape, with diameters up to 6.5 x 4.5 mm, while the neck of the aneurysm was 4 mm wide. On computed tomography angiography, the aneurysm was seen as much larger and round, up to 4.7 cm in diameter and with a calcified wall. In the further course of treatment, the microcatheter was placed in the lumen of the aneurysm and the embolization spirals were set within. This resulted in a complete exclusion of the aneurysm from the circulation. Endovascular treatment for the giant OA aneurysm, such as coil embolization technique, might be successful for the complete exclusion from circulation of a giant and partially thrombosed aneurysm. [ABSTRACT FROM AUTHOR]

Reintroduction of grazing to counteract insect decline will lead to an increase of semi-open habitats. Semi-open habitats are highly heterogeneous, consisting of a mosaic of patches of trees or shrubs embedded in a matrix dominated by dwarf shrubs or grasses. Despite a lack of evidence, structural heterogeneity is expected to allow many species to co-occur, making semi-open habitats appear highly valuable for invertebrate conservation. We studied ground beetles in eight sites in two landscapes of Central Europe each encompassing semi-open, open, and forest habitats. Rapid response to environmental change and limited dispersal abilities make ground beetles an excellent model taxon to evaluate the effectiveness of such conservations measures. In both studied landscapes, ground beetle assemblages in semi-open habitats tended to be distinct and intermediate between those from the forest and open habitats. Species richness and functional diversity in semi-open habitats were similar to open habitats at site level. The majority of species entered the semi-open habitats, except for most threatened species, yet, few species were exclusively associated with semi-open habitats. We conclude that the continuous presence of many species in semi-open habitats likely results from mass effects rather than habitat heterogeneity per se. Our findings underline the conservation value of the existing forest, heathland, and grassland habitats over semi-open habitats which can, however, function as dispersal habitats and increase landscape connectivity. Strategies aiming at promoting semi-open habitats to counteract insect decline should target enhancing connectivity rather than the creation of habitats only. [ABSTRACT FROM AUTHOR]

Simple Summary: A growing high-grade glioma exerts a local pressure on its surroundings, resulting in a tissue displacement known as the gross mass effect that is considered a major cause of acute neurological symptoms in patients with brain cancer. Mass effects are usually manifested when significant deformations caused by the tumor growth are observed radiologically or clinically; however, minor deformations in peritumoral tissue could provide early evidence of processes related to tumor relapse and recurrence. In this study, we propose an automated method to quantify the subtle deformations that occur in the peritumoral region. We also propose four biomarkers for differentiating where peritumoral displacements translate into compression. Biomarkers quantifying peritumoral compression were found to be associated with patient progression and prognosis and demonstrated the ability to stratify patients between long-time and short-time survivors. We conclude that compression biomarkers can be key to early treatment assessment during follow-up. The compression of peritumoral healthy tissue in brain tumor patients is considered a major cause of the life-threatening neurologic symptoms. Although significant deformations caused by the tumor growth can be observed radiologically, the quantification of minor tissue deformations have not been widely investigated. In this study, we propose a method to quantify subtle peritumoral deformations. A total of 127 MRI longitudinal studies from 23 patients with high-grade glioma were included. We estimate longitudinal displacement fields based on a symmetric normalization algorithm and we propose four biomarkers. We assess the interpatient and intrapatient association between proposed biomarkers and the survival based on Cox analyses, and the potential of the biomarkers to stratify patients according to their survival based on Kaplan–Meier analysis. Biomarkers show a significant intrapatient association with survival (p < 0.05); however, only compression biomarkers show the ability to stratify patients between those with higher and lower overall survival (AUC = 0.83, HR = 6.30, p < 0.05 for CompCH). The compression biomarkers present three times higher Hazard Ratios than those representing only displacement. Our study provides a robust and automated method for quantifying and delineating compression in the peritumoral area. Based on the proposed methodology, we found an association between lower compression in the peritumoral area and good prognosis in high-grade glial tumors. [ABSTRACT FROM AUTHOR]

Comparing spatio-temporal patterns between planktonic and benthic algae is helpful for understanding their associations and differences. However, such studies are still rare especially in large rivers. We used a dataset collected in the upper reach of the Jinsha River in different seasons to explore biodiversity and assembly processes of planktonic and benthic diatom assemblages. We found that planktonic and benthic diatoms presented different seasonal variation in species richness and community compositions. We also found evidence that planktonic and benthic diatoms were coupled in the summer. Planktonic diatom assemblages were mainly affected by spatial processes via directional spatial dispersal, especially in the summer. By comparison, benthic diatom assemblages were more affected by environmental processes. Our findings suggest that mass effect and species sorting paradigms explain the assembly processes of planktonic and benthic diatom assemblages, respectively, but the explanatory powers of these two paradigms vary seasonally. To effectively monitor and assess ecological conditions of large rivers, we recommend using benthic algae as a biotic indicator group as they had stronger correlations with environmental factors. [ABSTRACT FROM AUTHOR]

Understanding how and why fish species composition varies between locations through beta‐diversity has received increased interest recently. The physical structure, extension and environmental characteristics along the river basins influence the dispersal of organisms, which ultimately affects metacommunity dynamics and biodiversity patterns. Here, we aimed to identify major breaks delimiting fish assemblages in a large dam‐free river basin on its main channel, which is almost pristine in hidrology, and to evaluate the influence of geo‐climatic variables in the observed beta‐diversity patterns. We used the statistical techniques Species Composition Interpolation (SCI) and Generalized Dissimilarity Modeling (GDM) to analyse beta‐diversity patterns based on georeferenced fish records from the Ivaí River basin. Ichthyofauna units were delimited, estimating the association between geo‐climatic predictors and beta‐diversity. We identified three major breaks delimiting fish assemblages in the Ivaí River basin (i.e. the upper, middle and lower sections). The fish communities were very distinct at the upper and lower sections, while the middle section was recovered as less differentiated. Turnover was the main component contributing to total beta‐diversity, and dissimilarity in fish species composition was moderately associated with geo‐climatic variables. Fish communities from the Ivaí River basin must be associated with niche‐based processes, and we hypothesize that dispersal processes can be equally significant at the basin scale. The investigations may produce insights on strategies for conservation and restoration of degraded rivers, contributing to the long‐term maintenance of fish communities and to the delimitation of new strategic areas for the effective conservation of freshwater biodiversity. [ABSTRACT FROM AUTHOR]

This study evaluates the temporal evolution of the spatial relationship between the pituitary adenoma transsphenoidal surgical cavity and the adjacent optic chiasm and discusses implications on timing and choice of radiotherapy modality. This retrospective observational review analyzed factors that might influence the postoperative relationship between the surgical cavity and the optic chiasm, including tumor type, craniocaudal tumor and resection cavity dimensions, the preoperative distance between tumor and the optic chiasm, the presence of cavernous sinus invasion, and the choice of intraoperative packing material. Changes observed on magnetic resonance imaging in the preoperative, immediate (within 72 h), and delayed (≥3 months) postoperative periods were compared. Sixty-five patient histories were analyzed. Preoperatively, the pituitary adenoma was apposed to the optic chiasm in 43 patients (66%). Postoperatively, 34 patients (52%) in the immediate postoperative period and 54 patients (83%) in the delayed postoperative period had a distance ≥2 mm between the resection cavity and the optic chiasm. This distance provides a greater margin of safety with adjuvant radiosurgery. Preoperative tumor size showed a strong association with postoperative descent of the optic chiasm. Preoperative tumor size and degree of mass effect on the optic chiasm predict postoperative changes. In this study, the distance between the resection cavity and the optic chiasm was greater at ≥3 months postoperatively than in the immediate postoperative period, regardless of preoperative mass effect, indicating radiotherapy planning should be deferred to ≥3 months postoperatively when not precluded by aggressive histological characteristics that necessitate more immediate treatment. To investigate the temporal relationship between the postoperative sellar surgical cavity and the adjacent optic apparatus after transsphenoidal resection of pituitary adenomas and the implications for radiotherapy. • MRIs were evaluated in 65 patients after transsphenoidal pituitary adenoma surgery. • A subset of these patients may require adjuvant radiotherapy. • Radiosurgery is safest when the optic chiasm is >2 mm from the resection cavity. • The surgical cavity involutes predictably, increasing distance from the optic chiasm over time. [ABSTRACT FROM AUTHOR]

The mechanisms of brain injury after intracerebral hemorrhage (ICH) involve mass effect‐induced primary injury and secondary injury caused by a pathologic response to the hematoma. Considerable attentions have recently been paid to the mechanisms and therapeutic strategy for secondary brain injury due to no overall benefit from early surgery compared with initial conservative treatment. However, it is unclear whether there is a causal relationship between mass effect and secondary brain injury. Here, the role of mass effect on early erythrolysis after experimental ICH was investigated based on the poly(N‐isopropylacrylamide) (PNIPAM) ICH model. Autologous blood and PNIPAM hydrogel were co‐injected into the right basal ganglia of rats to induce different degrees of mass effect, but with a constant hematoma. The influences of different mass effect and time courses on erythrolysis and brain damages after ICH were investigated. Furthermore, the protective effect of trehalose against erythrolysis after ICH was evaluated. The results showed that mass effect caused erythrocyte morphological change at 24 hr after ICH. The released hemoglobin was quantitatively evaluated by a polynomial concerning with the mass effect, the volume of hematoma, and the time of ICH. An obvious increase in heme oxygenase‐1 (HO‐1) and ionized calcium binding adaptor molecule‐1 (Iba‐1) expression, iron deposition, cell death, and neurological deficits was observed with increasing mass effect. Moreover, trehalose alleviated brain injury by inhibiting erythrolysis after ICH. These data demonstrated that mass effect accelerated the erythrolysis and brain damages after ICH, which could be relieved through trehalose therapy. [ABSTRACT FROM AUTHOR]

MS (multiple sclerosis) has specific criteria to avoid misdiagnosis. However, the Marburg variant of MS is so fulminant that initial axonal damage and other atypical observations have been allowed in past reports. We present a 74-year-old autopsy case with a vanishing tumor after steroids and radiation therapy, which was pathologically diagnosed as a Marburg variant with initial axonal loss. The case displayed radiological lymphoma-like observations: mass effects protruding to the lateral ventricle, fused extension from the choroid plexus to white matter with C opening sign, a growing lesion from the skull dura mater, high in diffusion-weighted imaging and low in apparent diffusion coefficient on magnetic resonance imaging (MRI) suggesting high cell density lymphoma. In addition, clinical manifestations were atypical for MS: upper limb monoplegia without ipsilateral lower limb involvement, pleocytosis over 50 cells/μL, and class 3 cytological abnormality in cerebrospinal fluid. However, at autopsy following steroids and radiation therapy, there were no lymphoma-like lesions, such as mass effects, fused extensive lesions, masses on the skull dura mater, or high cell density lesions. Instead, there were only myelin losses corresponding to the MRI lesions, highlighting the potential for contamination by other diseases in steroid-modified Marburg's variant of multiple sclerosis, possibly due to lymphoma, even at autopsy., Competing Interests: The authors declare that they have no conflicts of interest., (© 2024 The Authors.)

Bioassessment is widely used to measure ecological integrity of natural habitats following anthropogenic disturbances and modifications. Traditionally, bioassessment has been based exclusively on species-environment interactions, i.e. niche processes. However, dispersal processes, and in particular mass effect, could mask the influence of niche processes and lead to erroneous conclusions about ecosystem health. To circumvent this problem, we identified 40 diatom species with distributions driven primarily by mass effect and propose an alternative version of the Biological Diatom Index (IBD2007) excluding these species. We tested the environmental responses of both the original IBD (IBD2007) and the modified IBD (IBDmod) with a benthic diatom dataset from France, collected between 2007 and 2013 and including 9487 samples from 3913 spatially distinct localities. Our results indicate a better relationship between the IBDmod scores and environmental conditions, compared to the IBD2007 scores, leading to a more accurate determination of river ecological status, especially in conditions of moderate nutrient enrichment. This study supports the idea that mass effect may result in biased evaluation of water quality. It is advocated that this process is considered in other diatom-based indices, and by extension, in any biotic index.

Background: Many pancreatic pseudocysts spontaneously resolve, but larger or symptomatic pseudocysts may require procedural management. Though endoscopic ultrasound guided approaches are standard of care and have high success rates, complications can include bleeding, infection, and splenic perforation. This patient case report details an unusual series of complications of endoscopic cystogastrostomy that should encourage clinicians to evaluate for anatomic disruptions caused by mass effects of pancreatic pseudocysts prior to endoscopic pseudocyst drainage.Case Presentation: A 53-year-old African American male with a past medical history notable for alcohol use disorder, chronic pancreatitis, and insulin dependent diabetes presented with a 4-day history of left upper quadrant abdominal pain. Computed tomography imaging with contrast revealed enlargement of a known pancreatic pseudocyst to 15.9 × 10.4 cm. Due to pseudocyst size and the patient's symptoms, endoscopic cystogastrostomy stent placement was performed. However, postprocedurally, he developed leukocytosis to 19,800 cells/m3 (from 14,100 cells/m3 preoperatively) as well as acute hypoxemic respiratory failure with a large left pleural effusion. Postprocedural computed tomography with contrast demonstrated a new large subcapsular splenic hematoma in communication with a new subdiaphragmatic fluid collection. Due to suspicion of endoscopic procedural complication, he underwent open laparotomy which revealed grade 4 splenic laceration, septic splenic hematoma, and a subdiaphragmatic abscess.Conclusions: While endoscopic drainage of pancreatic pseudocyst was technically successful, this case demonstrates complications from mass effect of a large pancreatic pseudocyst which putatively tore the splenorenal ligament, leading to excessive separation of the left kidney and spleen. If anatomic disruptions caused by mass effect from a pancreatic pseudocyst are recognized through preprocedural abdominal imaging, such cases may be considered for early open repair versus cystogastrostomy. [ABSTRACT FROM AUTHOR]

Introduction: The mass effect caused by large and giant aneurysms of the internal carotid artery (ICA) was the cause of compression of the cranial nerves (CN) with the phenomena of gaze palsy, diplopia, cephalgia and visual disturbances. In this regard, it is relevant to use a method of treatment aimed not only at excluding the aneurysm from the bloodstream, but also a method that helps to reduce the size of the aneurysmal sac. The introduction of flow diverter (FD) is a promising method that can also be used to reduce the aneurysms’ mass effect. In this regard, our goal was to study the predisposing factors influencing the effect of “shrinking” of large and giant aneurysms of the internal carotid artery after the installation of flow diverters. Methods: From 2011 to 2020, 56 patients with large and giant ICA aneurysms were treated at our center with the use FD. For the analysis, we used only the data of 21 patients from this number, where FD were installed without additional coiling aneurysm. To solve the problem, the following factors were analyzed: the location of the aneurysm, the age of the patients, the average sizes of the dome, neck and dome-neck ratio, as well as the degree of aneurysm contrast filling after FD placement according to the O’Kelly Marrota classification (OKM). Results: According to our observations, the aneurysm’s location, patients’ age and dome, neck and domeneck ratio average sizes did not affect on the aneurysm’s shrinkage size. However, the A (28.7%) and B (33.3%) groups on the OKM scale showed the best results where the size reduction was more than 75% from the initial size. Whereas C (19%) and D (19%) grades showed the least aneurysm shrinking effect - up to 25% and 25-50% from the initial size, respectively. Conclusions: The predisposing factor that had the greatest influence on giant and large ICA aneurysms shrinking effect in our observations series was A and B grades by O’Kelly Marrota scale. [ABSTRACT FROM AUTHOR]