Social media has become an increasingly important tool in monitoring the onset and spread of infectious diseases globally as well monitoring the spread of information about those diseases. This includes the spread of misinformation, which has been documented within the context of the emerging COVID-19 crisis. Understanding the creation, spread and uptake of social media misinformation is of critical importance to public safety. In this descriptive study, we detail Twitter activity regarding spinal manipulative therapy (SMT) and claims it increases, or “boosts”, immunity. Spinal manipulation is a common intervention used by many health professions, most commonly by chiropractors. There is no clinical evidence that SMT improves human immunity.Social media searching software  was used to describe Twitter activity regarding SMT and improving or boosting immunity. Searches were performed for the 3 months and 12 months before March 31, 2020 using terms related to 1) SMT, 2) the professions that most often provide SMT and 3) immunity. From these searches, we determined the magnitude and time course of Twitter activity then coded this activity into content that promoted or refuted a SMT/immunity link. Content themes, high-influence users and user demographics were then stratified as either promoting or refuting this linkage.Twitter misinformation regarding a SMT/immunity link increased dramatically during the onset of the COVID crisis. Activity levels (number of tweets) and engagement scores (likes + retweets) were roughly equal between content promoting or refuting a SMT/immunity link, however, the potential reach (audience) of tweets refuting a SMT/immunity link was 3 times higher than those promoting a link. Users with the greatest influence on Twitter, as either promoters or refuters, were individuals, not institutions or organizations. The majority of tweets promoting a SMT/immunity link were generated in the USA while the majority of refuting tweets originated from Canada.Twitter activity about SMT and immunity increased during the COVID-19 crisis. Results from this work have the potential to help policy makers and others understand the impact of SMT misinformation and devise strategies to mitigate its impact. More than half of all persons on earth 53.5%) are estimated to now have regular internet access with 47% in low-middle income countries and 86.6% in high income countries . With th.5% are eSocial media has been used in recent decades to anticipate various health events including the spread of infectious disease  and new While all misinformation is concerning, the public does not expect misinformation to be propagated by regulated health professions whose activities are overseen for public protection. Unfortunately, this has not been the case during the COVID-19 outbreak. Claims that personal immunity can be improved or “boosted” through spinal manipulative therapy , an intervention applied by many professions but most commonly by chiropractors , appeareHas Twitter activity describing a relation between SMT and “boosting” immunity increased during the COVID-19 crisis?What is the magnitude and engagement of Twitter activity that promotes or refutes an SMT/immunity link?Does Twitter activity differ between health professions that are mentioned in relation to SMT and immunity?What are the demographics  of Twitter authors who promote or refute a SMT/immunity link?In this descriptive study, we detail how Twitter activity can be used to not only document the magnitude and time course of misinformation describing a link between spinal manipulative therapy (SMT) and boosting immunity, but how social media activity promotes or refutes these claims. Specifically, our study aimed to answer the following research questions:We anticipate that knowledge gained from answering these questions will be important not only in predicting future internet misinformation about SMT, but also in preventing and/or mitigating its impact.Social media searching was performed using Talkwalker Quick Search . Similar to tools used for searching health literature (e.g. EMBASE), Talkwalker performs searches of specific internet content including social media platforms, news agencies, forums and blogs. Talkwalker’s functionality allows searching to be limited to specific content sources, date ranges, electronic devices and many other parameters using standard Boolean syntax. Analysis of search results can be performed in several ways including descriptive metrics generated by Talkwalker using existing data (e.g. sex distribution), derived metrics generated by Talkwalker using artificial intelligence algorithms (e.g. sentiment) and user-generated metrics obtained by downloading raw search results directly into other software .For this project, Talkwalker searches were performed exclusively on Twitter for the 3 months before March 31, 2020. Twitter was searched preferentially for the following reasons. First, the entirety of Twitter is searchable (except for direct messaging which is a private discussion between Twitter users) compared to sources such as Facebook whose users must purposefully make their activity available for searching. Second, Twitter is a one-to-one communication model where direct dialogue is possible between all users compared to news media where unbalanced communication occurs through a one-to-many model. Finally, Twitter activity is unmoderated creating potential for a full range of conversation (except for content excluded by Twitter’s rules and policies).between searches , we performed additional searches to explore how search terms contributed to the primary search. Search #2 and Search #3 were performed to understand the impact of procedures and professions on the main search. Similarly, we conducted searches #4–8 to understand if procedure terms occurred more frequently for specific professions. Searches #9–13 were performed to understand how individual professions were linked specifically to immunity. Finally, Search #1 was performed again for the 12 months before March 31, 2020 as this is the longest period Talkwalker can search backwards in time (not listed in Table Our primary search Search #1) was constructed of three main components using Boolean syntax: 1) [procedure] terms related to SMT, 2) [profession] terms related to professions most often associated with SMT and 3) an immunity term [immun*]. In this study, we limited professions to be those that most often provide SMT . No additional filters were used (e.g. language). Procedure terms included wildcard representations of words commonly used to describe SMT including manipulation, adjustment and SMT. Profession terms included wildcard card representations of chiropractic, physical therapy, naturopathy, osteopathy and naprapathy. As Talkwalker lacks the ability to perform Boolean operations  was consThe above searches identified tweets that contained the search terms in the body of the tweet as words and/or hashtags (e.g. #chiropractic). For each individual tweet identified, multiple attributes describing its content were provided including date, creator, content, country of origin, language, likes, retweets, followers etc. A glossary of Twitter-related terms such as #hashtag can be found in Table The above searches resulted in mentions (see Table Tweets arising from Search #1 were first coded for their tone using the Twitter Tone Index (TTI). The TTI Table  is a nomFollowing TTI scoring, four evaluators  individually scored tweets arising from Search #1 regarding professions mentioned within each tweet . Tweets that did not mention a relevant profession were coded as “none mentioned”. Tweets not having at least 3 evaluators in agreement were discussed to agree on a majority rating. Unresolved ties were broken by a fifth evaluator (GK). Importantly, it was possible to code only whether tweets mentioned a profession; it was not possible to determine if or how the author was associated with a specific profession.The content of all tweets obtained from Search #1 were pooled, analyzed for word frequency by a public website , then seInfluencers were considered to be tweet authors having an engagement score (retweets + likes) of greater than zero. Tweets from each author were segregated by their TTI value and sorted by engagement score.Descriptive statistics from Search #1 were derived for each Twitter user including language, and country of origin using geographical coordinates.Total mentions over the 3 month study period are described in Table In the 12 months before March 31, 2020 Fig. , baselinThere were 1118 individual tweets generated from Search #1 Table . When coWhen these 1118 tweets were coded for the 5 professions related to SMT, there were 809 tweets where a profession was not mentioned and 7 tweets mentioning an irrelevant profession. Of tweets mentioning a profession relevant to SMT, some mentioned a single profession while others mentioned multiple professions; a distinction retained in our coding  or refuted (148 mentions) a link between SMT and immunity, chiropractic was mentioned 108/189 times (57%) in promoting tweets and 123/148 times (83%) in refuting tweets. Naturopathy was the next-most mentioned profession with 40/189 (21%) mentions in promoting tweets and 20/148 (14%) mentions in refuting tweets.The major themes (frequent words) contained within the 1118 tweets from Search #1 are presented in Table In total, there were 132 Twitter authors having engagement scores of > 0 for the study period. Table Demographics from Search # 1 were segregated by TTI value (promoting or refuting) and are displayed in Table This paper presents the novel finding that Twitter misinformation regarding a SMT/immunity link increased dramatically during the onset of the COVID crisis. Further, activity levels and engagement were roughly equal between tweets promoting a SMT/immunity link and tweets refuting this claim. Interestingly, the potential audience (reach) of tweets refuting these claims was 3 times higher than those promoting these claims.The majority of search results (i.e. mentions) from Search #1 were coded as not relevant on the TTI and did not mention a specific profession (778 (70%)). Combined with tweets having a neutral tone (12 (2%)), the vast majority of mentions from Search #1 were not relevant to our analysis. While our search terms could have been made more restrictive to reduce this number of irrelevant mentions , we preferred to err on the side of having too many search results that were then coded by our team rather than construct too narrow a search that potentially missed relevant tweets.Clearly, Twitter mentions about a SMT/immunity link increased during the onset of the COVID-19 crisis with peak activity being almost 5 x higher on March 9, 2020 (19.7 k mentions) compared to any other peak activity in the prior 12 months . This suggests that mentions during the COVID-19 crisis were intentional and not an aberration of baseline activity. To further assess baseline Twitter activity, we evaluated the second largest peak of mentions in the preceding 12 months . This activity consisted almost entirely of twitter content unrelated to the aims of the paper. However, our analysis did reveal a smaller activity peak on October 21, 2019 that appeared to be related to an automated message delivered from a web content subscription service.“Chiropractic care can improve your immune system, mobility, strength, and so much more. If you want to see a positive change in your health, schedule an appointment with us”.This specific tweet appeared in 17/21 unique tweets on October 21, 2019 within hours of each other. These 17 tweets generated a total potential reach of 54 users and an engagement score of 1 (retweets + likes). In contrast, a single tweet in the same time period that refuted this message generated a potential reach of 2657 users with an engagement score of 25.potential impact of a tweet. In contrast, if someone acknowledges a tweet by giving it a like or retweeting it (i.e. rebroadcasting it to their own followers), this confirms that the original tweet was both read and acknowledged indicating a true interaction between users. Considering this, tweets that refute a SMT/immunity link had almost 3 times the potential reach compared to those that promoted this link although the engagement between these two groups was similar. This is an important finding as it suggests that promoting tweets create as much engagement as refuting tweets but with the important note that refuting tweets have the potential of reaching many more persons with their message. Still, it is highly likely that the engagement and potential reach of promoting and refuting tweets have differing audiences who are unaligned in their belief systems about SMT and immunity [When a tweet is made, it automatically goes out to all persons who follow (i.e. subscribe) the author’s Twitter account. While sometimes the potential reach of that author is in the thousands or even millions, there is no guarantee that their followers open their device and see the tweet let alone read it. Therefore, the number of followers, or the potential reach of an author is a measure of the immunity .Regarding professions mentioned in tweets, our coding revealed that our initial wildcard search terms for physiotherapy and osteopathy were too broad resulting in tweets having topics related to physiology and osteology for example. Following coding to eliminate these tweets, chiropractic was the profession most often referenced with 4 times more mentions than the next profession (naturopathy). These data suggest that the majority of twitter activity regarding a SMT/immunity link is associated with the chiropractic profession with the total number of posts being roughly equal between those promoting and those refuting this link.Tweet themes do not appear to be a good indicator of the impact of specific content as the frequency of the theme is not related to the potential reach or engagement associated with the message; an infrequent theme may be posted in a tweet with far greater reach and engagement than higher ranked themes with lower reach and engagement.The top influencers for tweets promoting and refuting a SMT/immunity link each had engagement scores that were ~ 1000 points higher than the next influencer. This shows influence distribution is not equal within each group. Even more so, top influencers appear to be individuals and not academic institutions, regulatory bodies or professional organizations. Thus, few institutions  were identified as influencers although some individuals with a specific institutional affiliation could be identified. Although Twitter data is publicly available, and Twitter users agree to make their information available publicly, we have chosen not to identify user names of influencers so as not to inadvertently legitimize those who promote misinformation.The majority of those promoting or refuting a SMT/immunity link were male and English speakers. Interestingly, tweets promoting a SMT/immunity link most commonly originated in the United States. Although tweets rarely were affiliated with specific institutions, we note that the majority of chiropractic, naturopathic and osteopathic schools in the world are in the United States. In contrast, the majority of tweets refuting a SMT/immunity link were from Canada which suggests that geographic proximity between countries is not a factor in establishing a position on this topic. These data likely reflect the distribution of Twitter use around the world. The United States is the number one user of Twitter with Japan in second place and Canada in 12th place .Results from this work have the potential to help policy makers and others understand the impact of SMT misinformation and devise strategies to mitigate its impact. Specifically, our results suggest that while the potential reach of messaging that refutes misinformation about SMT was substantial, very few institutions added to this total. Assuming that most institutions related to SMT stand to gain from combating misinformation about SMT , these same institutions should re-evaluate their social media strategies lest their silence be taken to be complicit of misinformation or lead to their own demise from an erosion of public trust.The results reported here are different from those presented previously by investigators who explored chiropractic messaging on Twitter in December of 2015 . In thisWhile Talkwalker can assess other electronic data sources, only Twitter provides full access to its “firehose”, the entirety of its activity except for direct messaging between users (a private channel of communication between users). As a result, the data from this paper are presumed to be robust in that they represent all activity taking place on a single social media platform although search results from Talkwalker have not been compared against other services/techniques for accessing Twitter data.Although Twitter provides a window into conversations within a social media community, it is limited in that it does not represent all persons in the world. Presently, Twitter ranks 13th in total monthly users; Facebook has 2.45 billion active monthly users compared to Twitter’s 340 million .Some of the data used in this study were obtained from proprietary algorithms available from TalkerWalker Quick Search but whose methods of calculation were not available to us (e.g. sentiment scores). Similarly, Talkwalker Quick Search uses artificial intelligence to derive some demographic information not directly included in Twitter user profiles . These proprietary metrics of defining user profiles were not used in our analysis.Twitter activity regarding misinformation about spinal manipulation and immunity increased above baseline levels during the COVID crisis. Direct Twitter activity  was similar between tweets promoting and refuting a SMT/immunity link. Importantly, tweets refuting a SMT/immunity link had the potential to be viewed by 3 times more people than tweets promoting this link. Whether promoting or refuting in tone, the chiropractic profession was most often mentioned in tweets compared to other professions associated with SMT provision. Results from this work have the potential to help policy makers and others understand the impact of SMT misinformation and devise strategies to mitigate its impact.


Fluid therapy is administered to veterinary patients in order to improve hemodynamics, replace deficits, and maintain hydration. The gradual expansion of medical knowledge and research in this field has led to a proliferation of terms related to fluid products, fluid delivery and body fluid distribution. Consistency in the use of terminology enables precise and effective communication in clinical and research settings. This article provides an alphabetical glossary of important terms and common definitions in the human and veterinary literature. It also summarizes the common routes of fluid administration in small and large animal species. Fluid therapy is an important component in the treatment of many hospitalized veterinary patients. The breadth of literature on fluid therapy-related concepts and management strategies is continually expanding and clarity in the use of the terminology is essential for effective communication and patient care. Using incorrect terms can lead to misunderstanding, misinterpretations, and inappropriate therapeutic decisions. The first aim of this article is to provide a glossary of key terms with reference to definitions found in the veterinary and human medical literature. Commonly used abbreviations, synonyms, and related words are listed after the associated term, where applicable. An expanded definition is provided for any term for which there is no widely accepted definition. The second aim of this article is to describe the different routes of fluid administration in veterinary species.For the glossary, a list of fluid therapy related terms was compiled based on common terms encountered in the fluid therapy literature pertaining to intravenous fluid classifications, intravenous fluid administration strategies, body fluid volume and hydration, body fluid compartments, body fluid composition, and acid-base balance. A systematic PubMed/MEDLINE search and literature review of the veterinary and human medical literature was performed between January to October 2020 to search for individual terms in the title, key words or abstract. The full glossary term was used as the search term by itself, individually as well as with the addition of the following words: “definition,” “veterinary,” and if needed, included terms denoting to specific veterinary species such as “dog,” “cat,” or “horse.”. For example, the search strategy for “Acute Normovolemic Hemodilution” used the following search terms: “acute normovolemic hemodilution,” “acute normovolemic hemodilution definition,” “acute normovolemic hemodilution veterinary,” “acute normovolemic hemodilution dog” and “acute normovolemic hemodilution cat.” Publications were considered if they were available in English and were published or in press. A minimum of 3 articles were reviewed for each search term, up to a maximum of 6 articles. Priority was given to articles from journals with a high impact factor, veterinary journals, and consensus-type articles, as well as the most recently published definitions. Case reports, comments, editorials and letters to the editor were excluded because they rarely contained definitions. The full text of all identified articles were screened for definitions to one or more glossary terms and multiple articles were evaluated in order to determine the degree of agreement. If the literature search revealed inconsistencies in the definition for any particular term, the literature search was expanded, and the most commonly encountered definition was provided with the addition of a notation mentioning the lack of widespread consensus. Where multiple similar terms could be used describe the same concept, the most frequently encountered term was listed in the glossary and synonyms were provided at the end of the applicable definition.A reduction in total circulating blood volume. Absolute hypovolemia can be caused by dehydration  or the loss of blood from the body or into a body cavity  , 2.+) when dissolved in water (aqueous solution) (A substance that is capable of increasing the concentration of hydrogen ions (Holution) .A blood pH that is below the normal physiologic range for the species in question .A process in which there is a net accumulation of acid in the body .isovolemic hemodilution.A blood conservation strategy where a specific volume of whole blood is removed from the patient and stored, and replaced by sufficient volumes of crystalloid or colloid solutions to restore intravascular volume prior to surgery. The rationale of this technique is to reduce the loss of red blood cells from surgical bleeding through hemodilution, thereby lowering the need for allogenic blood transfusions. The reserved blood is subsequently returned to the patient during or after surgery . SynonymCirculating blood protein weighing 69 kDa that is synthesized by the liver and is the major determinant of plasma oncotic pressure  and bicarbonate (HCO3−)  .+ + K+) − (Cl− + HCO3−). Anion gap is useful to help narrow down the potential causes of metabolic acidosis  , 11. Synbalanced isotonic electrolyte solution, polyionic crystalloid solution, or balanced salt solution.A fluid that contains an electrolyte composition  that is similar to that found in plasma. A balanced solution should maintain or normalize acid-base balance and be isosmotic and isotonic  with normal plasma , 12, 13.+) when dissolved in water  .+, K+, Ca2+) or molecule  , 8.autotransfusion.See Measurement of venous blood pressure within a large central vein, or more specifically, the cranial or caudal vena cava . A contrAlterations in the properties of a solvent due to the addition of solutes. Colligative properties depend on the concentration of molecules in solution, rather than the type of chemical species present , 20. ExaLarge molecular weight molecules (>30 kDa) that are preferentially retained in the intravascular space following intravenous administration. Types of natural colloids include plasma and albumin. Synthetic colloids include hydroxyethyl starches, dextrans, and gelatins , 21.oncotic pressure.The osmotic force generated by large molecules (colloids) in solution when separated by a semipermeable membrane from a region with a different colloid concentration . The colbiophysical therapy  or within cells (cellular edema) , 42.An electrolyte (ion) that exerts an osmotic force  across a semi-permeable membrane. Effective osmoles determine a solution's tonicity. Sodium ion is the predominant effective osmole in the body .Dissolved ions in solution that carry a positive or negative electric charge, such as sodium, potassium, chloride, and calcium .A negatively charged, mesh-like layer on the luminal surface of vascular endothelial cells, composed of membrane-bound glycoproteins and proteoglycans, which have an important role in regulating vascular permeability, endothelial anticoagulation and modulating interactions between the endothelium and the vascular environment , 44–46. Normal circulating blood volume , 47.Delivery of fluids to a patient through an enteral or parenteral route . The ratdaily fluid balance, cumulative fluid balance.The net difference between bodily fluid gains or inputs  and fluid losses or outputs  over a specified time period , 50. InsRapid intravenous administration of a small or large volume of fluid for the purpose of restoring tissue perfusion, such as during the treatment of hypovolemic shock , 51–53.Rapid intravenous administration of a modest volume of fluid, usually a crystalloid, in order to assess the likelihood of volume-responsiveness in a patient with hemodynamic instability, while minimizing the risk of fluid overload , 54. A fDescribes the distribution pattern of total body fluid within several well-defined spaces separated from each other by cell membranes . TogetheThis term has two different situation-dependent meanings. Fluid creep describes the administration of IV fluid to burn patients in excess of fluid requirements calculated by the Parkland Formula , 57. ThiIntravenous fluid administration .volume overload, which refers to excess fluid in the intravascular fluid compartment, or overhydration, which describes excessive pure water gain in the body.An increase in total body fluid  in excess of physiologic requirements. Some publications define it as a 10% or more increase in total body weight due to fluid administration which represents the threshold for an increased risk of adverse clinical effects such as pulmonary edema, peripheral edema or body cavity effusion , 59–61. 2O) or an increase urine output    or a dec+Cl−) , 13, 75.A colloid solution with an oncotic pressure above that of plasma  .Increased (supraphysiologic) blood flow to the tissues .A crystalloid solution with a higher effective osmolality than plasma  .A sterile hypertonic intravenous crystalloid composed of water, sodium and chloride. Available in multiple concentrations including 3%, 5% and 7.2% , 78.turbostarch.A resuscitation fluid containing a hypertonic crystalloid (>310 mosmol) and a hyperoncotic (>5%) colloid that is used as an alternative small volume fluid resuscitation strategy to rapidly increase intravascular fluid volume in the treatment of hypovolemia  , 80. Synfluid overload.Excessive circulating blood volume , 61. SeeA colloid solution with an oncotic pressure below that of plasma  .Insufficient blood flow to the tissues, resulting in decreased oxygen delivery. End-organ hypoperfusion can manifest as cool extremities, reduced pulse quality, oliguria and tachycardia , 82.permissive hypotension.See A crystalloid solution with a lower effective osmolality than plasma (e.g. 0.45% sodium chloride: 154 mOsm/L) . A solutInsufficient intravascular fluid volume, which may be absolute such as from dehydration and hemorrhage, or relative such as with vasodilatory shock , 83.Small dissolved particles in solution that contribute to total osmolality but do not exert an osmotic pressure because they freely cross and equilibrate across cell membranes  .Body fluid losses that cannot be easily measured, such as evaporative losses from the skin and respiratory tract, and the water content of stool , 86.The total volume of extracellular fluid contained within the interstitial tissues surrounding cells  .The total volume of fluid contained within cells  .The total volume of extracellular fluid contained within arteries, veins and capillaries in the circulatory system  .volume depletion.Reduction in intravascular fluid volume, which is a type of extracellular fluid volume depletion . RelatedA colloid solution with an oncotic pressure similar to that of plasma  .A crystalloid solution with an osmolality similar to plasma. The two types of isotonic crystalloids are isotonic saline (0.9% sodium chloride) and balanced solutions  .acute normovolemic hemodilution.See Hyperlactatemia with concurrent metabolic acidosis –93. LactTotal body weight minus the weight of fat. Calculated as 80% of ideal body weight when 20% of total body weight is fat .Term applied to randomized trials investigating the effect on morbidity and mortality of a conservative (restrictive) fluid strategy, compared to a standard  fluid regimen. Many standard fluid regimens are more likely to result in a positive fluid balance –97.Large and medium-sized arteries and veins that serve as conduit vessels, transporting blood to and from organs and tissues .A type of crystalloid solution that is designed to maintain hydration by meeting daily water and electrolyte requirements , 23, 86.A fluid therapy plan designed to provide water and electrolytes in quantities that meet normal daily fluid needs and replace urinary, gastrointestinal, and evaporative losses .Loss of > 40–50% of total blood volume over 3 h or less, or > 100% of total blood volume over 24 h .Replacement of > 40-50% of total blood volume over 3 h , 99, or Blood vessels <200–300 micrometers in diameter, consisting of small arteries, arterioles, capillaries, and venules , 102–104Hyperchloremic metabolic acidosis.See sotonic saline.See ieuvolemia.See colloid osmotic pressure.See A measure of the concentration of osmotically active particles per unit volume of solution, measured in milliosmoles per liter of solution (mOsm/L) , 22, 105A measure of the concentration of osmotically active particles per unit mass of solution, measured in milliosmoles per kilogram of solution (mOsm/kg) , 22, 105The process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated solution, thus equalizing the concentrations on both sides of the membrane .Administration of food or medication through a non-enteral  route, such as intravenous, subcutaneous, intramuscular and intradermal .A fluid resuscitation protocol for burn patients which calls for lactated Ringer's solution dosed at 4 ml/kg/%TBSA, where %TBSA refers to the percentage of the total body surface area burned , 109. HaThe passage of fluid through the circulatory system to organs and tissues , 110.hypotensive resuscitation.A fluid therapy technique that aims to provide enough resuscitation fluid to ensure adequate end-organ perfusion while maintaining mild hypotension (systolic pressures <90 mmHg) until definitive hemorrhage control can be achieved , 33, 111The liquid portion of blood that remains after the cells are removed. Plasma is retrieved by centrifugation of an anticoagulated blood sample, and so unlike serum, it contains fibrinogen and clotting factors .An automatic measure of the dynamic change in perfusion index (PI), as determined by a pulse oximeter, occuring during a complete respiratory cycle. The pulse oximeter derived pulsatile signal is indexed against the non-pulsatile infrared signal and expressed as a percentage [PI = (AC/DC) × 100] reflecting the amplitude of the pulse oximeter waveform. The pulse variability index is calculated as PVI = [(PImax – PImin)/PImax] × 100 .balanced crystalloid solution.See A complex biomolecule predominantly made of polypeptides that is found in all living matter .The difference between arterial systolic and diastolic blood pressure measured in millimeters of mercury (mm Hg) .The difference between the maximum (PPmax) and minimum (PPmin) arterial pulse pressures during one respiratory cycle, divided by their sum divided by 2 ([PPmax + PPmin]/2) and expressed as a percentage . Pulse pTime needed for a pulse wave to travel between two arterial sites . Due to Hypovolemia produced by diuresis induced by rapid bolus fluid administration to conscious animals .A reduction in the effective circulating blood volume due to venodilation and increased venous capacitance . RelativA type of crystalloid solution that is isotonic, has a composition similar to extracellular fluid, and is administered to replace water and electrolyte losses  , 23.A conceptual framework that describes four different stages of fluid resuscitation, beginning with initial rapid fluid administration to treat life-threatening shock (Rescue), continued fluid therapy until adequate perfusion is restored (Optimization), followed by ongoing maintenance fluids (Stabilization), and gradual discontinuation of fluid support  , 121.fluid resuscitation.See Starling Principle.An updated version of the traditional Starling equation that incorporates current understanding of the role of the endothelial glycocalyx in transvascular fluid filtration , 123. ReMeasurable body fluid losses, such as urine, vomit, and diarrhea , 86.hypovolemic shock refers to reduced effective circulating volume, from internal or external intravascular fluid loss  divided by systolic blood pressure (SBP) . SI >1.0The relative elasticity of the skin, used as an estimate of hydration status , 130. Skin vitro to 1 L of fully oxygenated whole blood to return the sample to standard conditions , at a hemoglobin concentration of ~50 g/L  that needs to be added  ~50 g/L , 131. Unbase excess of the extracellular fluid (BEEcf). Related term: base excess.Synonym: Fluid flux across the capillary wall is determined by a balance of hydrostatic and oncotic pressures such that fluid leaves the capillary at the arterial end of the capillary and is absorbed at the venous end of capillary .unstressed vascular volume.The volume of blood within a vein that produces a transmural pressure above zero , 132. CoThe difference between maximum and minimum stroke volume during one respiratory cycle, divided by their mean, and averaged over several breaths . Stroke A cation and anion that are considered to be fully dissociated at physiologic pH , 135. ThThe difference between the concentrations of strong cations and strong anions in plasma –136.+, K+, Mg2+, Ca2+) with the common anions  and other measured non-volatile weak acids (A−). SIG is calculated as SIDa – SIDe, or more specifically, as [Na+] + [K+] + [Mg2+] + [Ca2+] – [Cl− corrected] – [lactate] - [A−] – [SIG quantifies [unmeasured anions] – [unmeasured cations] of both strong and weak ions. It is reflects the difference between the activity of all common cations  , 152.Fluids are typically administered to veterinary patients through enteral, subcutaneous and intravenous routes , 48, 153Subcutaneous or enteral fluids can be considered in small animal patients with mild to moderate fluid deficits. Compared to intravenous fluid administration, there is a lower limit to the amount of fluid that can be delivered by these routes. In the presence of severe dehydration and hypovolemia, avoid fluid replacement by the subcutaneous route due to the potential for decreased absorption resulting from peripheral vasoconstriction , 48.Where larger volumes of fluid are necessary but venous access cannot be obtained , placement of an intraosseous (IO) catheter may be considered , 157. DeWhen voluntary oral intake is insufficient or undesirable, fluids can be rapidly and inexpensively administered by nasogastric tube to horses , 160 andAlternative fluid administration sites have also been described. A 6-h crystalloid infusion given per rectum was reported to be safe and well-tolerated in horses , althougDespite the frequency with which fluids are administered to veterinary patients, developing an effective fluid management plan may at times be surprisingly complex. A thorough understanding of the physiology of body fluids, fluid administration routes, therapeutic delivery strategies, risks, and complications will help to optimize patient outcomes. National and multinational organizations, such as the International Fluid Academy (IFA), provide opportunities for clinicians and researchers to promote research and education in the practice of fluid therapy. The use of clear and consistent terminology is a key component to fostering effective communication and collaboration within the veterinary and human healthcare fields.The author confirms being the sole contributor of this work and has approved it for publication.The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Hydrous fluids released from subducting oceanic lithosphere fuel arc magmatism and associated hydrothermal mineralization, including formation of porphyry copper deposits. Critical magma degassing parameters are the depth, chemistry and style of fluid release during magma ascent, notably the behaviour of chlorine, a key metal-transporting ligand. Currently, understanding is limited by restricted data on fluid-melt partitioning of chlorine as a function of pressure and magma chemistry, and the complex interplay between the two that occurs in polybaric magmatic systems. Here we present experimental determinations of chlorine partitioning as a function of fluid and melt composition at pressures from 50 to 800 MPa. We provide, for the first time, a quantitative understanding of chlorine and copper evolution that is valid for shallow, deep or transcrustal differentiation and degassing. Monte Carlo simulations using our new data reproduce the chemical evolution of melt inclusions from arc volcanoes and fluid inclusions from upper crustal intrusions and porphyry copper deposits. Our results not only provide a novel chemical framework for understanding magma degassing, but quantify the primacy of magmatic chlorine concentration at the point of fluid saturation in promoting efficient copper extraction from magmas. Chlorine behaviour during complex, polybaric arc magma degassing is poorly understood. Here, the authors show that chemical feedbacks during coeval magma differentiation and degassing account for the Cl record at both volcanoes and ore deposits, and quantify the role of Cl in efficient copper extraction during degassing. Volcanic gas plumes and hydrothermal ore deposits are two manifestations of this degassing process. Although there is consensus that volatile-rich magmas are responsible for arc volcanism, plutonism and hydrothermal mineralization3, the manner of fluid release is keenly debated, with decompression (“first-boiling”) or cooling and crystallization (“second-boiling”) the main drivers4. Conventional concepts predicated on second-boiling of large, relatively volatile-poor (≤5 wt% H2O) melt-rich “magma chambers” in the shallow crust7 are now being challenged by models of vertically extensive, long-lived, mid- to lower-crustal crystal mushes containing a volatile-rich (8–15 wt% H2O) intergranular melt13. Such high dissolved H2O concentrations create problems for standard approaches to tracking magma degassing using H2O and CO2 because the latter is extensively degassed by the time magmas reach shallow sub-volcanic or ore-forming domains. More generally, emerging views on these “trans-crustal” magmatic systems14 invoke volatile release from chemically diverse arc melts over a wide pressure range that need to be considered in modelling both volcano degassing and hydrothermal ore formation.Volatile-rich subduction zone magmas release substantial volumes of halogen-bearing and sulphur-bearing H17, so the behaviour of chlorine is key to elucidating both degassing style and ore formation. Only by quantifying chemical feedbacks across the full range of differentiation paths can we evaluate the magmatic cycling of volatiles and ore metals under various degassing scenarios. Furthermore, by using Cl and H2O as probes of the degassing process, we circumvent problems with traditional use of CO2 and H2O (e.g. ref. 4) that arise because extensively degassed, evolved magmas typically have very low dissolved CO2 concentrations.First- and second-boiling processes impact differently on the behaviour of incompatible fluid-mobile elements, such as chlorine and copper, during degassing. In natural systems, fluid-mobile elements evolve along paths intermediate between these two end-members through competition between enrichment via crystallization and depletion by fluid exsolution Fig. . The exa20 identified pressure as a key control on chlorine partition coefficients  to determine fluid composition. Experiments utilizing robust mass-balance methods were very limited in pressure and composition space  was augmented by data from ref. 17 and a set of low-salinity (<20 wt% NaCleq) fluid + andesite experiments30. Full experimental details are provided in the “Methods” section; run conditions and analyses in 2 and trace metal chloride species  throughout this study to describe the total Cl concentration of the fluid, irrespective of its speciation.To address the lack of appropriate fluid-melt partitioning data we performed fluid-saturated experiments at 50–800 MPa, 800–950 °C using as starting materials natural metaluminous calc-alkaline rhyolite, dacite and andesite to which were added NaCl–KCl–HCl solution and quartz cylinders. An in-situ quartz fracturing technique31). This is in marked contrast to an existing 19 that suggests steady increase in 19. The apparent partial molar volume of NaCl in aqueous fluids  and an exponential function of melt SiO2 (wt%) and fluid salinity (wt% NaCleq)D0, a, b and c are constants and P0 is the inflection point. A weighted regression of the data (n = 38) yields the following parameter values:Our entclass1pt{minima2O concentration) and always falls along the defined metaluminous calc–alkaline compositional trend . While all degassing paths start at a melt fraction of 1 at varying SiO2 concentrations, the evolution of the melt fraction and melt composition was parametrized from a compilation of experimental data (see the “Methods” secton). This range of fluid saturation conditions (both in pressure and melt composition) and variable degassing paths serves to examine a wide range of possible degassing scenarios from shallow, deep or trans-crustal degassing of andesitic to rhyolitic magmas. For each modelled path we compute also the weighted average of the fluid fractions degassed at each increment in order to approximate the aggregated fluid composition discharged from the entire underlying system28. Note that, in nature, degassing will be some mixture of instantaneous and aggregated degassing modes depending on the style of fluid ascent and accumulation throughout degassing. Our models implement the latest H2O–CO2 solubility algorithm32; alternative formulations do not greatly change the key findings. We do not explicitly include the effects of CO2 on fluid chemistry or chlorine partitioning, although we recognize that this is a rich area for further study, especially if arc magmas have high initial CO2 concentrations33.To explore chlorine evolution during magma degassing we incorporated Eq.  into a M34 and Mount Hood35, by identifying a subset of random differentiation paths that matches the observed range of SiO2 and 2O solvus at low pressure when the single-phase fluid separates into a hypersaline liquid (or ‘brine’) and a low salinity vapour , crystallization (increasing SiO2), and evolving fluid salinity during degassing in a manner not possible using existing parameterizations  data from two arc volcanoes, Mount St. HelensH2O Fig. . We tuneH2O Fig. . Our modH2O Fig.  as well H2O Fig. . Excursimentclass2pt{minimmentclass2pt{minim2O solvus. Two-phase (brine + vapour) fluid degassing will occur in some very shallow (<150 MPa) Cl-rich systems. Nonetheless, limited brine partitioning data are also available in the 6. The deeper more hydrous degassing paths are designed to mimic the conditions where deep compressional magma degassing might occur11.To explore magma degassing more broadly, we modelled the composition of the silicate melt and fluid (instantaneous and aggregated) for incremental equilibrium degassing using 10,000 mixed 1B–2B degassing scenarios Fig. –11. The 2O concentrations at the onset of fluid saturation . The example isobaric paths starting with more evolved melts show that they do initially exsolve higher salinity fluids  of ID fluid inclusions is best matched by an initial Cl/H2O weight ratio of ~0.04 , supercritical fluid inclusions from magmatic rocks likely sample single-phase fluids released at different stages of magmatic differentiation17. Experimental copper partitioning data for andesites39 show that this expression holds for the range of melt compositions modelled.We calculated the copper concentration in both instantaneous and aggregated fluids and the extraction efficiency of copper by the fluid  using a salinity-dependant 2) than the peak in salinity  cannot be reproduced by our model, suggesting that post-entrapment copper diffusion affected some ID fluid inclusions, especially at salinities <8 wt% NaCleq42. Indeed, our calculated aggregated fluids from differentiation paths that yield the highest ID fluid salinities (~7 to 12 wt%) have copper concentrations below ~1500 ppm  magmas, whereby elevated pressure keeps H2O in solution enabling sufficient chlorine and SiO2 enrichment for high 2) magmas at mid-crustal pressures (400–200 MPa) results in efficient extraction  liberates fluids at low entclass1pt{minimameltFig.  and low meltFig. . Therefouid Fig. .19 between degassing behaviour of volcanoes and formation of hydrothermal ore deposits. Moreover, the use of H2O and Cl as tracers of magmatic degassing provides a companion to more conventional pairs, such as H2O and CO2, when examining water-rich systems. Significantly, we show how a combination of elevated magmatic chlorine and moderate to deep differentiation of H2O-rich magmas45 are required to optimize efficient copper extraction upon magma emplacement in the upper to middle crust.We present a chemical framework to evaluate chlorine–water degassing systematics in transcrustal, subduction-related magmatic systems. Through Monte Carlo models of polybaric, chemical differentiation of fluid-saturated magmas we quantify the strong chemical feedbacks between degassing pressure and the chemistry of coexisting melt and fluids that helps bridge the “missing link”2) shows considerably greater variability in concentrations of chlorine (~50 to ≥5000 ppm)46 than of H2O (1.3–7.1 wt%)47. At any subduction zone the ultimate source of chlorine is likely subducted oceanic crust and sediments50. Variations in supply of chlorine  along an individual arc segment may be related to subducted fracture zones or seamounts49, interaction with chlorine-rich crustal lithologies, or sequential enrichment via cyclic differentiation9. The chemical controls and feedbacks on chlorine degassing and copper extraction efficiency identified here work in tandem with other physical controls, including geodynamic stress regime and fluid focussing, to influence the size and location of porphyry copper deposits. Thus, even chlorine-rich volcanic systems  and piston cylinder apparatus at the University of Bristol. For all experiments, ~50 wt% powdered natural igneous starting material was mixed with ~50 wt% aqueous NaCl–KCl–HCl solution (in Cl proportions 20:10:1) and was loaded into welded 3.8 mm (CSPV) or 3 mm (piston cylinder) OD gold capsules. Samples of rhyolite, dacite, and andesite from Laguna del Maule, Chile were used for the experiments (samples held as part of the collection at the University of Bristol). Compositions of the starting materials can be found in Experiments were performed in Inconel2 ~ NNO + 0.6). Using a rod-centreing, double-cone sealing technique, these vessels performed successfully for more than 1000 h total run-time at 800–850 °C (Type K thermocouples ±5 °C) at 300 and 400 MPa following more than 5000 h run-time at lower pressures. Run pressure was measured using both a Wika HP-2-S digital pressure transducer (0–420 MPa working range ±2 MPa uncertainty) and a certified analogue Heise pressure gauge (0–700 MPa working range ±10 MPa uncertainty). In experiments performed with the Inconel713LC CSPV apparatus (ƒO2 ~ NNO + 0.6), a cylindrical 2.5 mm OD core of unfractured, inclusion-free Brazilian quartz was loaded into the capsule to trap fluid inclusions. After 5 days at elevated pressure and temperature (i.e. when fluid and melt had equilibrated) the quartz was fractured in situ29 using a magnetic filler rod control system. Following fracturing, the experiments were left to run another 3 days to allow the quartz to “heal” and trap fluid inclusions. At the end of the experiment, a modest quench rate was used to cool the capsule to room temperature over ~1 min, which prevents re-fracturing the quartz while still allowing for the transformation of the melt to homogeneous glass.Experiments at 100–400 MPa were performed in custom-machined Inconel713LC CSPVs of 12″ length and ID/OD = 0.25″/1.0″ (ƒO2 pressurized (ƒO2 ~ NNO) CSPV to achieve the higher temperatures (950 °C) necessary to maintain significant melt fraction. Approximately 20–30% crystallization of the melt in these runs resulted in a trachydacitic final melt composition. The lower bulk SiO2 concentration meant that melt was not close to silica saturation, thus quartz cores could not be used to trap fluid inclusions; for these runs mass balance calculations were used to determine Cl partition coefficients. Type K thermocouples and digital pressure transducers were used to control run pressure (±2 MPa) and temperature (±5 °C) similar to CSPV runs.Andesitic-dacitic experiments (CMPA141 and CPMA281) were run in a TZM-alloy Ar–H2 control was established by placing a small  Ni–NiO–H2O-filled gold capsule at the bottom of the sample capsule. Temperature was measured with a Pt–Rh thermocouple in contact with the capsule. A friction correction appropriate to the salt-Pyrex assembly52 was applied. Formation of CO2 due to infiltration of elemental carbon from the graphite furnace was minimized by coating the capsules with haematite prior to placing them in the assembly. Examination of run-product fluid inclusions, prior to microthermometry, using a Thermo Scientific DXRxi Raman spectrometer at 532 nm using variable laser power and scan times revealed no detectable CO2 in any inclusions.Experiments at 800 MPa were run in half-inch (12.7 mm) end-loaded piston cylinder apparatus using a salt-Pyrex assembly. Gold capsules  were filled with the same glass starting materials and NaCl–KCl–HCl aqueous solution, along with a pre-fractured quartz core (in-situ fracturing is not yet possible in piston cylinder experiments at these conditions). ƒO2, Al2O3, TiO2, MnO, MgO, FeO, CaO, K2O, Na2O, P2O5) and volatiles  in glasses were acquired at University of Bristol using a five spectrometer JEOL JXA8530F Hyperprobe. An accelerating voltage of 15 kV and a defocussed beam diameter of 10 µm was used for all glass analyses. Major oxides were measured at a beam current of 2 nA to minimize diffusive loss of Na from the analytical volume53; S, Cl, F were measured subsequently on the same spot using 20 nA. Analytical accuracy was assessed by measuring a hydrous rhyolitic glass secondary standard. Between 12 and 20 analyses were averaged for each experiment. Water concentrations were determined using the volatiles by-difference (VBD) method. Average glass analyses for all experimental runs are reported in Compositions of the silicate glasses and salinity of the fluid inclusions recovered after quenching were measured directly by electron probe microanalysis (EPMA) and microthermometry, respectively. Solid run products were mounted in one-inch epoxy rounds, polished and carbon-coated. Major oxides . Starting material ratios of NaCl/KCl = 2/1 were assumed for the calculations; little impact is expected due to modification of this ratio as their colligative impacts on ice melting are indistinguishable55. During interaction with the melt some FeCl2 may have dissolved into the fluids; the presence of FeCl2 (2/3 of ions are Cl) instead of NaCl/KCl (1/2 of ions are Cl) results in a 33% increase in Cl concentration for the same 2 content predicted for our inclusions 17 results in ≤3% underestimation of the Cl concentration, below the analytical scatter in the fluid inclusions assemblages.Microthermometric measurements were made using a Linkam THMS600 heating–freezing stage at University of Bristol. Measurements of the ice melting point (±0.1 °C) were input into the SALTY salinity model54. However, our At least fifteen synthetic fluid inclusion analyses were conducted from at least five assemblages to ensure a robust sampling of trapped fluids. Three of the new experiments produced co-existing vapour-brine assemblages. Brine salinity was evaluated using the halite and sylvite dissolution temperatures30 were used in the calibrant dataset to supplement the low SiO2 end of the melt evolution spectrum. The relevant experiments at 50 and 100 MPa were adjusted by applying the calculated56 brine–saturated vapour salinity value rather than using the reported bulk salinity calculated by mass balance. The adjusted vapour salinity was used to recalculate Data from ref. 67 for eq).Additional literature datasetsentclass1pt{minimaσP) were propagated onto the predicted 68. Using this calibration, we can reproduce literature Parameters of Eq.  were det2O, SiO2, Cl and Cu concentrations were randomly drawn and considered to represent the degassing conditions of a wide range of plausible water-saturated metaluminous calc–alkaline magmas. Degassing paths starting from these points were generated by a random combination of first boiling (decreasing H2O) and second boiling (increasing SiO2). Within the population of random paths, specific degassing paths linked to common models for differentiation are highlighted for reference. Melt H2O concentrations of water-saturated magmas was linked to pressure through a parametrized equation  is defined asm refers to mass. In the course of crustal magmatic evolution, F decreases as a result of crystallization  and/or decompression . At each calculation step (i), we model this by randomly drawing values of 0 or 1 for δF be the variation in melt fraction (F) between two successive steps. In order to extract a comparable mass of fluid from decompression or crystallization steps, the ratio (rδ) between the size (mass fraction of degassed H2O) of a crystallization step (i), the mass of each component is given byConsidering a fluid-saturated magma , the melt mass fraction  was defined as a function of SiO2  along a calc-alkaline differentiation trend by parameterizing published water-saturated experimental data76 using a fifth-order polynomial. A reference melt composition (Fr = 100%) was chosen at 55 wt.% SiO2 and the final (eutectic) melt was constrained at 79 wt% SiO2  concentration of SiO2 in the melt at the point of fluid-saturation was randomly selected within the input range of values. Each data series then follows the parameterized calc-alkaline trend , and the corresponding relative melt fraction at each step  was calculated asThe relative mass fraction of melt (2 in the melt at each step was obtained by solving Eq. (Using ving Eq.  using a i) both crystals and exsolved fluid leave the system, the bulk partition coefficient at each increment is:fluid) depends on fluid salinity, at each step this parameter was solved incrementally using Eqs.  ad ad44. ThFor each degassing path, we computed the salinity and Cu concentration of the aggregated extracted fluid as a weighted mean of the fluid fractions degassed at each increment along the path:For each path the Cu extraction efficiency was defined asSupplementary InformationDescription of Additional Supplementary FilesSupplementary Data 1


S)-(−)-[18F]fluspidine in imaging studies in an orthotopic mouse model of GBM (U87-MG) as well as in human GBM tissue. A tumour-specific overexpression of sig1R in the U87-MG model was revealed in vitro by autoradiography. The binding parameters demonstrated target-selective binding according to identical KD values in the tumour area and the contralateral side, but a higher density of sig1R in the tumour. Different kinetic profiles were observed in both areas, with a slower washout in the tumour tissue compared to the contralateral side. The translational relevance of sig1R imaging in oncology is reflected by the autoradiographic detection of tumour-specific expression of sig1R in samples obtained from patients with glioblastoma. Thus, the herein presented data support further research on sig1R in neuro-oncology.Glioblastoma multiforme (GBM) is the most devastating primary brain tumour characterised by infiltrative growth and resistance to therapies. According to recent research, the sigma-1 receptor (sig1R), an endoplasmic reticulum chaperone protein, is involved in signaling pathways assumed to control the proliferation of cancer cells and thus could serve as candidate for molecular characterisation of GBM. To test this hypothesis, we used the clinically applied sig1R-ligand ( Glioblastoma multiforme (GBM) is the most common primary tumour of the central nervous system. Although the global incidence is rare with less than 10 per 100,000 people, the median survival rates for patients with GBM remain dramatically low despite complex surgical, pharmacological and radiation therapy approaches . An impo18F]FDG), amino acid transport (by [11C]MET or [18F]FET), and membrane turnover (by [18F]FMC) FMC) ,14. They18F]FMC) , or the 18F]FMC) , reflect18F]FMC) .+ channels, volume-regulated Cl− channels, or endoplasmic reticulum Ca2+ release FMSA4503 [18F]SFE or [18F]FTC-146 [11C]SA4503 and (S)-(−)-[18F]fluspidine were applied in research on the in vivo imaging of sig1R in brain tumours using heterotopic brain tumour models, as by the group of van Waarde, or orthotopic models, as by our group SF]FTC-146 ,38. Howeur group ,40.18F]fluspidine for clinical trials , the promising results of a collaborative pilot study in an orthotopic mouse model of GBM [18F]fluspidine-PET to characterise brain tumours on a molecular level. We report herein on the assessment of GBM-specific expression of sig1R by a combination of in vitro and in vivo approaches using mice bearing intracranial U87-MG tumours as a preclinical orthotopic model of human GBM and the sig1R-specific radioligand (S)-(−)-[18F]fluspidine. Initially, we validated the in vivo selectivity of (S)-(−)-[18F]fluspidine for sig1R in a sig1R-knockout mouse model. Then, we validated by radioligand binding assays the suitability of the U87-MG cell line used for the orthotopic GBM model regarding the presence of the target, and confirmed by autoradiography the unimpaired overexpression under in vivo conditions. By immunohistochemistry as radioligand-independent method, we could confirm the expression and overexpression of sig1R protein in U87-MG cells in 2D culture as well as in the cellular environment of the mouse brain. Finally, we performed dynamic PET/MRI (magnetic resonance imaging) studies to assess the pharmacokinetics of (S)-(−)-[18F]fluspidine in the orthotopic U87-MG mouse model of human GBM, and report on the very first detection of sig1R protein in human GBM tissue by means of in vitro autoradiography, validating the relevance of this target.Encouraged by the approval of the in-house developed radiopharmaceutical (S)-(−)-pentazocine, an established sig1R-specific radioligand, a Bmax value of 129 fmol/mg protein and a KD value of 2.4 nM was determined. Specific binding of (S)-(−)-fluspidine towards (+)-[3H]pentazocine-labeled binding sites in U87-MG cells has been proven by displacement studies, and the affinity of (S)-(−)-[18F]fluspidine to sig1R has been determined with a KD of 16.7 nM.We initially evaluated the expression of sig1R in U87-MG cells, a human primary glioblastoma cell line, grown in 2D cell culture by radioligand binding assays and immunohistochemistry to determine their suitability for the intended orthotopic mouse model of GBM. By a single saturation assay using (+)-fluspidine confirmed the expression of sig1R in orthotopically growing U87-MG cells. The autoradiographic images presented in 50 = 17.4 nM [18F]fluspidine in the orthotopic tumour reflects a heterogeneous accumulation of activity within the tumour, similar to what was observed by immunohistochemistry on cellular level. By saturation studies, performed as homogenous radioligand displacement experiments by co-incubation of (S)-(−)-[18F]fluspidine with different concentrations of (S)-(−)-fluspidine, we determined the kinetic binding parameters of (S)-(−)-[18F]fluspidine in the tumour (T) and an internal reference region, the contralateral striatum (CL). In both regions, (S)-(−)-[18F]fluspidine bound specifically and with comparable affinities of KD, T = 17.5 ± 1.3 nM and KD, CL = 17.0 ± 4.8 nM. However, the sig1R density was ~1.7 times higher in the tumour area compared to the CL area, as reflected by values of Bmax, T = 704 ± 16 fmol/mg protein vs. Bmax, CL = 414 ± 36 fmol/mg protein.Complementary autoradiography performed with the sig1R-specific PET tracer (S)-(−)-[ 17.4 nM ) -(−)-[18F]fluspidine in sig1R-knockout (n = 1) and control (n = 3) mice with the main focus on the tracer kinetics in the striatum. Mean injected activity was 3.5 MBq and 1.9 MBq with a molar activity of 24 GBq/µmol and 21 GBq/µmol at the time of injection, resulting in a mean chemical concentration of 4.7 nmol/kg and 3.2 nmol/kg in the control group and the sig1R-knockout mouse respectively. The corresponding time-activity curves (TACs) are presented in S)-(−)-[18F]fluspidine  along with a much stronger and faster washout observed in the sig1R-knockout mouse in comparison to the control animals  confirming the selectivity in vivo of (S)-(−)-[18F]fluspidine for sig1R (S)-(−)-[18F]fluspidine.Due to access to a limited number of sig1R-knockout mice , we perfor sig1R A. In ordS)-(−)-[18F]fluspidine, we proceeded with PET studies with (S)-(−)-[18F]fluspidine performed under baseline conditions in nude mice-bearing orthotopic U87-MG (n = 3). Mean injected activity was 9.1 MBq with a molar activity of 92.5 GBq/µmol at the time of injection, resulting in a mean chemical concentration of 4.2 nmol/kg. The tumour growth was assessed by MRI with a T2-weighted sequence, and a 60 min dynamic PET scan, followed by T1- and T2-weighted sequences, performed when the tumour size was 28 ± 8 mm3 . The regions-of-interest (ROIs) were delineated on the T2-weighted MR images and then applied on the PET data to generate the regional TACs.Encouraged by the in vitro and in vivo findings on the specific expression of sig1R in orthotopically grown U87-MG tumours and the sig1R-specific binding of (S)-(−)-[18F]fluspidine in the tumour is lower and more slowly than the activity uptake in the control region with maximal SUV values of 0.82 at 3 min p.i. and 1.24 at 1 min p.i., respectively. However, because the washout from the tumour was slower, the tumour and CL TACs intersected at about 30 min p.i., demonstrating with SUVs of 0.38 and 0.28 at 60 min p.i. a higher retention of activity in the tumour region compared to the CL, respectively. The retarded washout of the sig1R-specific (S)-(−)-[18F]fluspidine from the orthotopic tumour is in accordance with the autoradiographic data, indicating a higher availability of sig1R in the U87-MG tumour tissue in comparison to CL.As reflected by the TACs presented in S)-(−)-[18F]fluspidine into the tumour (S)-(−)-[18F]fluspidine may also  be caused by reduced blood supply to the tumour centre. The PET image at later time points -(−)-[18F]fluspidine using cryosections of tissue samples obtained from 3 patients diagnosed with Glioblastoma multiforme IV. Total and nonspecific binding of the PET ligand was determined by incubation with only (S)-(−)-[18F]fluspidine or with co-administration of a high concentration of haloperidol to block the sig1R, followed by histological staining of the respective cryosections. As shown in S)-(−)-[18F]fluspidine in all three GBM samples with the highest density in regions histologically characterised by a high density of cells which we assume might be related to the highly proliferating tumour cells. Accordingly, although it was not possible within this preliminary study to confirm by immunohistochemistry the distribution pattern of sig1R in the cryosections or to identify the type of cells possessing high specific binding of (S)-(−)-[18F]fluspidine, these preliminary data motivate us to design a complementary study on the investigation of sig1R protein in a larger number of GBM samples by means of specific radioligands and antibodies.To initially assess the suitability of sig1R as specific target for molecular characterisation of human GBM, we performed in vitro autoradiography with (S)-(−)-[18F]fluspidine for the analysis of the expression of sig1R in GBM.In this study, we evaluated the availability of sig1R in an orthotopic mouse model of human GBM. High expression of sig1R in different cancer cell lines derived from prostate, breast, colon, melanoma, small and non-small cell lung cancer, brain tumours including GBM, neuroblastoma, and meningioma have already been reported ,46,47,483H]pentazocine, a selective sig1R ligand widely applied in radioligand binding assays pentazocine in other cancer cell lines such as 42 fmol/mg protein in the C6 murine glioblastoma cells, 76.5 fmol/mg protein in the NB41A3 neuroblastoma cells or 1115 fmol/mg protein in the U-138-MG cells fluspidine, indicate the conservation of sig1R expression and conformation over the translation from in vitro culture to in vivo implantation. Furthermore, the cytoplasmic localization of the sig1R fluorescence signal which was observed in vitro and in the explanted brain tumours matches with the cellular localization of the receptor found in rat astrocytes and mouse neurons fluspidine in both regions indicate that the PET radiotracer binds to the same target, i.e., the sig1R, in both compartments. The analysis of the binding parameter Bmax excludes conformational differences between sig1R in cancer and normal cells, as discussed by Kim et al., as a possible reason for the higher accumulation of sig1R-targeting radioligands in tumour tissue, but clearly indicates an about 2-fold higher density of sig1R in the U87-MG tumour in comparison to the healthy brain [S)-(−)-[18F]fluspidine obtained mainly by pharmacological intervention studies [S)-(−)-[18F]fluspidine in the orthotopic brain cancer model and no relevant interaction with off-target binding sites in vivo.Subsequently, we quantified the number of sig1R expressed in the U87-MG tumours implanted in the right striatum as well as in the internal control region, the left striatum. The equivalent hy brain . Thus, t studies ,65, we m studies . In acco11C]SA4503 by the group of van Waarde SA4503 PET studies mentioned above. However, we assume that this discrepancy is related mainly to the characteristics of the background region, in particular the physiological expression of sig1R in the different grafting sites. An ectopic tumour obtained by e.g., implantation of C6 glioma in the shoulder in the soft tissue [S)-(−)-[18F]fluspidine in healthy mice fluspidine in vivo. The U87-MG tumour is known to be highly vascularised and presenting necrotic foci [11C]SA4503 in the tumour outer rim was reported in the already mentioned PET study of the ectopic C6 glioma model as well as in a patient with non-small cell lung cancer in the tumour tissue [11C]SA4503 and [18F]FDG [18F]FDG PET images may be misleading due to an increased glucose metabolism in noncancerous but inflammatory tissues, the authors suggested the use of sig1R PET imaging to discriminate between tumour and inflammation fluspidine on cryosections of human glioblastoma obtained from three patients consistently showed a heterogeneous distribution of binding sites of the sig1R-targeting radioligand with high-density binding in cell-dense regions as suggested by the subsequent histological analysis. However, although sig1R appears to play a role in proliferation, this preliminary examination does not allow to speculate about a correlation between receptor expression and tumour proliferation but nevertheless suggests to design a respective large-scale study fluspidine was prepared on a TRACERlab FXN synthesizer  as described in previous publications [18F]fluspidine was >99%, and the molar activity (Am) at the end of the synthesis (EOS) was 89–180 GBq/µmol (n = 2).Enantiomerically pure  in Dulbecco’s Modified Eagle Medium  supplemented with 10% heat inactivated fetal bovine serum , 5% penicillin and streptomycin, 1.25% sodium pyruvate, 1% l-glutamine  and 1 µg/mL puromycin  only for the transfected cells.U87-MG cells  and human hsig1R-transfected Human Embryonic Kidney (HEK) cells  were maintained in monolayer culture  with the Sig1R agonist (+)-[3H] pentazocine  in incubation buffer  without  or with co-incubation of 1 µM haloperidol  at room temperature for 60 min. The incubation was terminated by filtration via a Whatman® glass microfibre filter  at room temperature for 90 min), followed by quadruplicate washing with 50 mM TRIS-HCl, pH 7.4/4 °C using a semi-automated cell harvester . Filter-bound radioactivity was detected in terms of DPM/vial by liquid scintillation counting  of the isolated filters immersed for two hours in liquid scintillation cocktail . Specific binding (SB) was calculated by SB  = TB  − NB . The Bmax and the KD values were estimated by a nonlinear regression model (equation: one-site binding (hyperbola)) using GraphPad Prism, Version 4.1 .Cell membrane homogenates of U87-MG cells were obtained by gentle scraping the cells grown to confluency in one 175 cm2, 1 mM MgCl2) at room temperature for 15 min. The pre-incubation solution was decanted, the slices dried again under a stream of cold air, and covered afterwards with the incubation solution ((S)-(−)-[18F]fluspidine, 197 kBq/mL incubation buffer = 4.5 nM at the time of incubation, without  or with co-incubation with 1 µM haloperidol to assess nonspecific binding). Incubation at room temperature was terminated after 60 min, the slides were washed two times in 50 mM TRIS-HCl, pH 7.4 at 4 °C, on ice for two minutes each followed by dipping in ice-cold demineralized water for 5 s and rapid drying under a stream of cold air. Afterwards, the slides were exposed to a phosphor imager plate  along with standards obtained by pipetting and drying 1 µL of each concentration of a serial dilution of the radioligand solution on to a microscopic slide. The exposed phosphor-imaging plates were scanned using a high resolution scanner  at a laser spot size of 12.5 µm (pixel size: 12.5 µm2) followed by two-dimensional analysis of the digitized images . The tracer distribution in the autoradiographic images obtained for total and nonspecific binding was compared by visual inspection and correlated with the histochemical staining (Nissl- and Hematoxiline-eosin staining) of the corresponding tissue sections.Cryosections of brain tumour tissue from three patients (Glioblastoma multiforme IV) were obtained using a microtome , mounted on microscopy slides , dried for ~2 h at room temperature, and stored at −25 °C until the autoradiography study. For the experiment, the slides were taken out from the freezer, the cryosections dried under a stream of cold air, and pre-incubated with incubation buffer -(−)-[18F]fluspidine in buffer for 60 min at room temperature. Nonspecific binding was determined in the presence of 10 µM of SA4503  or 100 µM to 10 nM of (S)-(−)-fluspidine, respectively. Developed autoradiographs were analysed in a phosphor imager . The quantification was performed by using 2D-densitometric analysis . The Bmax and the KD values were estimated by a linear regression model (equation: one-site binding (hyperbola)) using GraphPad Prism, Version 4.1 .Cryosections of brains obtained from female athymic nude mice (Rj:NMRI-Foxn1 nu/nu) , were obtained as described above. The same protocol as in ® 488; ab150117, Abcam, Berlin, Germany). A Hoechst counterstaining, 10 min at room temperature, was performed to visualize the nuclei of the cells . After a step of washing and drying, slides were cover up with mounting medium. . Visualization of the slides was performed by fluorescence microscopy .Tissues were cryopreserved by incubation in 2-Methylbutane at −25 °C . The brains were cut into coronal sections 10 µm thickness with cryostat  and kept at −25 °C. Immunostaining was performed after fixation in PFA 4% for 20 min at 4 °C of the slides. Detection of the sig1R protein was performed by overnight incubation at 4 °C of the slides with the primary mouse monoclonal antibody . After washing with a solution of 1% BSA in PBS, the slides were incubated for 1 h at room temperature with the secondary polyclonal goat anti-mouse antibody  and were injected 3.0 mm into the brain parenchyma with a flow of 0.1 μL/min using a 10 μL Hamilton syringe. After injection, the burr hole was filled with bonewax , the scalp incision sutured  and the surface antiseptically cleaned. Animal sacrifice was performed by induction of anesthesia with a mixture of air and isoflurane concentrate followed by cervical dislocation.Female athymic nude mice (Rj:NMRI-Foxn1 nu/nu) were chosen for this study . The mice were used for tumour implantation at the age of 8 weeks (26–30 g). During microsurgery mice were anesthetized with a mixture of air and isoflurane concentrate (1.5–2% depending on the breathing) under sterile conditions. The mice were placed into a Stoelting stereotactic frame . A midline incision was done and a burr hole was drilled 0.5 mm anterior and 2.5 mm lateral to the bregma. 5 × 10n = 3; age: 10 weeks; weight: 30–35 g) or nude mice   and one CD-1 sig1R-knockout mouse   were kept in a dedicated climatic chamber with free access to water and food under a 12:12h dark:light cycle at a constant temperature of 24/26 °C. The animals were anaesthetized  with isoflurane  delivered in a 60% oxygen/40% air mixture  and maintained at 37 °C with a thermal bed system. (S)-(−)-[18F]fluspidine was injected into the lateral tail vein  followed by a 60 min PET/MR scan . Each PET image was corrected for random coincidences, dead time, scatter and attenuation (AC), based on a whole body (WB) MR scan. The list mode data were sorted into sonograms using a framing scheme of 12 × 10 s, 6 × 30 s, 5 × 300 s, 9 × 600 s. The reconstruction parameters for the list mode data are: 3D-ordered subset expectation maximization (OSEM), 4 iterations, 6 subsets, energy window: 400–600 keV, coincidence mode: 1–5, ring difference: 81. The mice were positioned prone in a special mouse bed (heated up to 37 °C), with the head fixed to a mouth piece for the anesthetic gas supply with isoflurane in 40% air and 60% oxygen. The animal head was positioned in the center of the field of view in order to benefit from the highest spatial resolution possible . A dynamic PET scan of a duration of 60 min was performed followed by a T2 weighted sequence  and a T1 weighted sequence  for anatomical orientation and AC correction respectively. Image registration and evaluation of the region of interest (ROI) was done with PMOD . The respective brain regions were identified using the T2 weighted sequence and the tumour area and the contralateral area were delineated manually. The hypersignal due to the tumour in T2 weighted images was manually segmented and described as “tumour ROI”, and due to the compression of the contralateral side a fixed circled shape ROI was used to delineate the striatum avoiding nearby structure . The image-derived input function (IDIF) was extracted from a voxel of interest (VOI) segmented on the inferior vena cava (IVC). The IVC was identified using the first time frames showing the first passage of (S)-(−)-[18F]fluspidine bolus. An automatic algorithm from PMOD was used to identify the IVC signal avoiding heart and kidney area fluspidine, to investigate the tumour-specific expression pattern of sig1R by in vivo imaging. Whether the inferior outcome in vivo in comparison to in vitro is caused by the physiological expression of sig1R in the healthy brain or by certain pathophysiological characteristics of the orthotopic mouse model of GBM, remains to be elucidated. Nevertheless, this first evaluation of the sig1R availability in an orthotopic in vivo model of brain tumour contributes to a better understanding of this model and suggests an expression of sig1R in the tumour periphery as found in other studies, which may be related to proliferation and invasiveness. In conclusion, the data obtained in the U87-MG mouse model of GBM along with the detection of sig1R in human GBM tissue for the first time by a PET radioligand, indicate not only the relevance of this target but also the suitability of (S)-(−)-[18F]fluspidine for sig1R-targeted cancer research and drug development.To conclude, we showed for the first time in an orthotopic GBM model, the U87-MG mouse model of glioblastoma and the suitability of a sig1R-targeting PET radioligand, (


Transport measurements show the topological Hall effect in this heterostructure for temperatures below 100 K. Furthermore, Lorentz transmission electron microscopy is used to directly image Néel-type skyrmion lattice and the stripe-like magnetic domain structures as well. The interfacial coupling induced Dzyaloshinskii–Moriya interaction is estimated to have a large energy of 1.0 mJ m−2. This work paves a path towards the skyrmionic devices based on van der Waals layered heterostructures.The promise of high-density and low-energy-consumption devices motivates the search for layered structures that stabilize chiral spin textures such as topologically protected skyrmions. At the same time, recently discovered long-range intrinsic magnetic orders in the two-dimensional van der Waals materials provide a new platform for the discovery of novel physics and effects. Here we demonstrate the Dzyaloshinskii–Moriya interaction and Néel-type skyrmions are induced at the WTe 2/Fe3GeTe2 van der Waals heterostructure and a Dzyaloshinskii–Moriya interaction with a large energy density of 1.0 mJm−2.Strong magnetic interfacial coupling in van der Waals heterostructures provides a new platform for discovering novel physics and effects. Here, the authors report the formation of skyrmion lattice in the WTe Since the discovery of the ferromagnetism in Cr2Ge2Te66, CrI310, and Fe3GeTe2 (FGT)14, such layered crystals have been at the frontier of material research. Besides the material itself, interfacial engineering in vdW heterostructures offers an effective methodology to spin-polarize or valley-polarize two-dimensional (2D) materials. Proximity effect from the interface has been widely researched for spin or valley polarization in 2D materials, like graphene on transition metal dichalcogenides19 and WSe2 on CrI323. Coupling 2D magnets to vdW materials not only lends the magnetic properties of these 2D magnets to the adjacent materials, but also modifies the magnetic properties of the 2D magnets themselves24. Among all the possible interfacial coupling for 2D magnets, spin orbit coupling proximity can play an important role when the atoms of 2D magnets are in contact of heavy elements, considering that the magnetic properties are intrinsically related to the spin orbit coupling.Atomically thin, layered van der Waals (vdW) materials have been experimentally shown to host long-range magnetic orders recently25, where the broken inversion symmetry at the interface can change the magnetic states. DMI has been recognized as a key ingredient in the creation, stabilization, and manipulation of skyrmions and chiral domain walls. Whereas skyrmions from DMI become significant in the heavy metals/ferromagnet systems28, there have been no direct observations of skyrmions in vdW heterostructures, even though the topological Hall effect has been reported in Cr-doped topological insulator (TI)/TI29 and Mn-doped TI systems30.Rashba spin–orbit coupling is known to lead to a strong Dzyaloshinskii–Moriya interaction (DMI) at the interface2/FGT vdW heterostructures from transport measurements. More importantly, a large DMI energy of 1.0 mJ m−2 has been determined in this system and the formation of Néel-type skyrmions has been captured with Lorentz transmission electron microscopy (L-TEM). The sizes of the directly observed skyrmions are  ~150 nm at 94 K and  ~80 nm at 198 K. This work helps promote 2D materials for ultra-compact spintronic devices.In this work, we have observed the topological Hall effect in WTe2 and FGT separately. The 1T’ crystal structure of WTe2  as shown in Fig. 2/Si sample. Topological Hall is a spin-chirality-driven Hall effect, i.e., the spin chirality induces a finite contribution to the Hall response. In our case, dips and peaks near the magnetic phase transition edge, which signal the presence of the topological Hall effect, show up below 100 K as shown in Fig. 2/30L FGT heterostructure (sample B) shows the perpendicular magnetic anisotropy is well preserved in FGT when the temperature is below 180 K in the Fig. 12, and this will be confirmed later. Compared to the sample A as shown in Fig. 2/40L FGT and 2L WTe2/30L FGT heterostructures, the latter of which is similar to sample B and we also confirm a large DMI at the interface.WTe33, L-TEM, as one of the most direct methods to observe magnetic domain structures, domain walls and skyrmions, affords the advantage of a spatial resolution below 5 nm. The contrast formed in L-TEM is traditionally explained from the deflection of electrons due to the Lorentz force. For the Néel-type skyrmions, no contrast could be observed in the L-TEM image if the sample is not tilted because the intensity change caused by the Lorenz force at any point in the Néel-type skyrmion is compensated or canceled. After tilting the sample, dark-bright contrast could be formed in the L-TEM image34 due to the contributions from both the outside and the core of the Néel-type skyrmion as schematically shown in Fig. 2/40L FGT heterostructure at 180 K for the rotating angle α = 30°  is shown in Fig. z direction, having dark on the top side and bright in the bottom. The size is estimated to be  ~150 nm (more information about the skyrmion size of  ~150 nm at 100 K and  ~80 nm at 197 K can be found in Supplementary Note 2/4L FGT samples (similar to sample A) using L-TEM. This may be due to the small sheet magnetization in the thin film, which requires higher beam exposure to resolve; however, this already exceeds the tolerance of our samples, beyond which, unrecoverable damages occur. L-TEM measurements of WTe2/FGT heterostructures with varied FGT thicknesses suggest the DMI only penetrates to a finite depth of FGT  at the interface of the vdW heterostructure. Further researches can include electrically gating to control skyrmions in 2D vdW heterostructures, and this may open a new area in the field of ultra-compact next-generation spintronics.In summary, we reported the observed Néel-type skyrmions from L-TEM and the discovery of topological Hall effect in the WTe2/Si substrate. Then the PDMS/PPC on the glass slide was used to pick up the h-BN from the SiO2/Si substrate by heating up to around 40 °C. After that, we aligned the PDMS/PPC/h-BN and the exfoliated WTe2 on the 300-nm-thick SiO2/Si substrate, and used the similar heating temperature to pick up WTe2. Then we used PDMS/PPC/h-BN/WTe2 to pick up FGT. By heating the samples up to 110 °C, PPC was released from the PDMS and the PPC/h-BN/WTe2/FGT was transferred onto the prepared bottom electrodes. Then acetone was used to remove the PPC thin film. Another way to assemble the samples is using the pick-up transfer method to form the PDMS/PPC/WTe2/FGT layers first. After transferring the layers onto the bottom electrodes, the h-BN layers were used to cover WTe2/FGT later, as shown in Supplementary Note 2. In both cases, the WTe2/FGT interface is well preserved. The metal contacts used for the transport measurements of FGT thin flakes have two types, one is evaporation of Cr/Au electrodes after exfoliation of FGT onto the SiO2/Si substrates and the other one is using the pick-up transfer technique to accurately align FGT with the prepared bottom Cr/Au electrodes. The length and width of contacts in a Hall bar geometry as shown in Fig.In preparation, we coated the polydimethylsiloxane (PDMS) stamp on a glass slide with a polypropylene carbonate (PPC). During the assembly of heterostructure, we first exfoliated h-BN onto the 300-nm-thick SiOThe in situ L-TEM imaging was carried out by using a FEI Titan Cs Image TEM in Lorentz mode (the Fresnel imaging mode) at 300 kV.Supplementary InformationPeer Review File


Background: The relationship between varicella-zoster virus (VZV)-associated myelitis and aquaporin-4 immunoglobulin-G (AQP4-IgG) remains unknown.Case Report: We report a case of acute radiculomyelitis with longitudinal extensive hyperintensity signals traversing the brainstem until the upper thoracic cord in a 55-year-old healthy woman following herpes zoster infection in the left C4-T3 dermatome. VZV-specific IgG in the cerebrospinal fluid (CSF) and AQP4-IgG positivity on enzyme-linked immunosorbent assay (ELISA) were undetectable. Thus, she was diagnosed with immune-competent VZV radiculomyelitis. Forty-two months later, she experienced a relapse, and AQP4-IgG positivity was detected on ELISA. A cell-based assay (CBA) showed AQP4-IgG positivity not only at the time of recurrence but also retrospectively at 1 month after the initial symptoms. We concluded that AQP4-IgG-positive neuromyelitis optica spectrum disorder (NMOSD) was concurrent with VZV myelitis. After the second attack, she was treated with azathioprine and has had no relapse since then.Conclusion: We reported a case of VZV radiculomyelitis with confirmed concurrent AQP4-IgG positivity. NMOSD induced by herpes zoster has been recently identified, but distinguishing it from VZV myelitis can be difficult and whether these two diseases aggravate each other is unknown. Awareness of the potentially varied presentation of VZV myelitis can enable earlier recognition and proper treatment. Neuromyelitis optica  is considered an idiopathic inflammatory syndrome associated with severe attacks of optic neuritis and longitudinally extensive transverse myelitis (LETM), previously thought to be without brain involvement. Further advances have since been made due to the discovery of specific NMO-immunoglobulin-G (IgG)/aquaporin-4 (AQP4) antibody, the clinical and neuroimaging spectrum of NMO was further broadened by the International Panel for NMO Diagnosis (2015) to NMO spectrum disorder (NMOSD), wherein cerebral, brain stem, diencephalic lesions were also recognized with MRI. Both CNS lesions, and the presence of NMO-IgG/AQP4 antibody distinguish NMOSD from multiple sclerosis (MS). Moreover, the loss of AQP4 immunoreactivity and astrocyte pathology in the brain and spinal cord further discriminate NMOSD from MS.Helicobacter pylori and Chlamydia pneumoniae infections are reported as risk factors for AQP4-IgG-positive NMOSD  analyses in patients with NMOSD suggest that autoimmune or infectious disorders possibly trigger disease onset . Among nve NMOSD . Some reve NMOSD , 4–6. Seve NMOSD . Conversve NMOSD , 8–11.VZV myelitis, a rare disease that mostly affects immunocompromised patients and is caused by direct invasion of VZV of the spinal cord and occasionally, the spinal roots, presenting as radiculitis. In some cases, VZV myelitis is also observed in immunocompetent patients and described as LETM. The clinical course and long-term prognosis of immunocompetent patients are distinct from those of immunocompromised ones, perhaps because of the unforeseen effects of the immune process .Distinguishing VZV myelitis from AQP4-IgG-positive NMOSD preceded by herpes zoster is critical for appropriate treatment. Although some studies have reported AQP4-IgG-positive NMOSD induced by herpes zoster infection, there is limited evidence on the co-occurrence of AQP4-IgG-positive NMOSD and VZV myelitis. Here, we report a case in which VZV radiculomyelitis co-existed with AQP4-IgG-positive NMOSD and review the relevant literature.A 55-year-old female complained of a pruritic skin lesion on the area involving the left C4-T3 dermatome. She visited a dermatologist who diagnosed dermatomal VZV infection and prescribed valaciclovir hydrochloride. Two weeks later, the skin lesion began to subside gradually, but she experienced bilateral numbness of the upper extremities, which progressively worsened, with development of dysesthesia of the right side of the face. A month after VZV infection, she was admitted to our hospital. Her medical history included gastroesophageal reflux disease and bilateral cataracts. Her physical examination revealed a minimal eschar near her left ear. Neurological examination showed dysesthesia of the right side of the face, neck, bilateral upper extremities, and T4-T10 levels. The examination of other cranial nerves was unremarkable. There was no note of muscle weakness or atrophy. Tendon reflexes were increased in all extremities with the Babinski reflex present bilaterally. Urine incontinence was also observed. Spinal magnetic resonance imaging (MRI) revealed LETM, extending from the lower part of the medulla oblongata to C5, with marked edema and moderate gadolinium enhancement . AbnormaThe patient's second episode took place 42 months later. She experienced severe dysesthesia in her right hand, which gradually worsened after 2 days, and she started to experience right-sided dysesthesia for a second time. This was now accompanied by general unsteadiness. She had no skin lesions at this time. Upon consultation, ataxia with mild weakness in her right upper and lower extremities were noted. Spinal cord MRI showed a relapse of LETM in C3-T2, and CSF analysis revealed lymphocytic pleocytosis (30 cells/μl). VZV was undetected on PCR, and the VZV-specific antibody index was negative. However, the results of ELISA for serum AQP4-IgG were positive. We diagnosed her with AQP4-IgG-positive NMOSD and started her on IVMP 1 g once daily for 3 days, followed by oral prednisolone 40 mg/day, which was gradually tapered to 6 mg/day, and azathioprine 50 mg/day. These were continued and she experienced no relapse since. We theorized that she already had AQP4-IgG during the initial attack that went undetected. Thus, we tested the serum obtained during first admission using cell-based assay (CBA), and true enough, AQP4-IgG was detected . We concAQP4-IgG is a pathogenic marker of NMOSD. Asymptomatic AQP4-IgG seropositive status may exist for years before clinical NMOSD presentation ; hence, In our patient, during the initial attack, LETM from the medulla to the cervical spine led to the suspicion of NMOSD. However, AQP4-IgG was undetectable on ELISA, and the VZV antibody index was found to be increased in the CSF. Moreover, MRI revealed radiculomyelitis corresponding to the contiguous zoster dermatomes. Consequently, we diagnosed the patient with VZV radiculomyelitis and did not further examine AQP4-IgG using the highly sensitive CBA, which requires a specialized laboratory set-up. However, during recurrence 42 months later, the patient was found to have seroconverted to AQP4-IgG positivity and was thus diagnosed with AQP4-IgG-positive NMOSD. Based on the positive result of the retrospective examination of AQP4-IgG by CBA during the initial attack, we concluded that NMOSD co-existed with VZV radiculomyelitis.There is also growing evidence suggesting that the clinical course and long-term prognosis of VZV myelitis may be different in immunocompromised and immunocompetent patients. A study suggested that immunocompetent patients with VZV myelitis were mostly women, aged 18–47 years, with myelitis in the cervical or thoracic spinal cord and with benign disease courses. These characteristics were consistent with those of AQP4-IgG-positive NMOSD. In some cases, these immunocompetent patients did not show anti-VZV antibody and VZV DNA in the CSF, and data on AQP4-IgG were not acquired . We specThe pathophysiology of concurrence between VZV myelitis and AQP4-IgG is not known. Previously, NMO was attributed to VZV , and theOur case report has some limitations. Our case was diagnosed clinically and without histopathologic documentation of direct invasion of VZV in the spinal cord, which are mostly observed in immunocompromised patients with VZV myelitis . To provIn conclusion, while the diagnostic criteria of NMOSD requires exclusion of other diseases, we should take into account that concurrence of VZV radiculomyelitis with AQP4-IgG-positive NMOSD can occur and thereby alter the disease course. Further, we need to know the frequency of these coexistences. Therefore, when VZV myelitis is diagnosed, repeated examinations for AQP4-IgG are recommended.Written informed consent was obtained from the individual for the publication of any potentially identifiable images or data included in this article.HE performed the data research and wrote the paper. HT and SN treated the patient. MK, AN, AF, and JF supported the clinical interpretation. HM and YS were critically involved in the theoretical discussion and composition of the manuscript. All authors read and approved the final version of the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.