Synthesis and Identification of decarbamoyloxySaxitoxins in Toxic Microalgae and their Reactions with the Oxygenase, SxtT, Reveal Saxitoxin Biosynthesis.

Saxitoxin (STX, 1) is a representative compound of paralytic shellfish toxins (PSTs) that are produced by marine dinoflagellates and freshwater cyanobacteria. Although several pathways have been proposed for the biosynthesis of STX, the order of ring and side chain hydroxylation, and formation of the tricyclic skeleton have not been well established. In this study, 12,12-dideoxy-decarbamoyloxySTX (dd-doSTX, 2), the most reduced STX analogue having the tricyclic skeleton, and its analogues, 12ß-deoxy-doSTX (12ß-d-doSTX, 3), 12α-deoxy-doSTX (12α-d-doSTX, 4), and doSTX (5), were synthesized, and these compounds were screened in the toxic microalgae using high-resolution LCMSMS. dd-doSTX (2) and 12ß-d-doSTX (3) were identified in the PSTs-producing dinoflagellates (Alexandrium catenella, A. pacificum, and/or Gymnodinium catenatum) and in the cyanobacterium Dolichospermum circinale (TA04). doSTX (5), previously isolated from the dinoflagellate G. catenatum, was also identified in D. circinale (TA04). Furthermore, the conversion of 2 to 3, and 4 to 5, by SxtT with VanB, a reported Rieske oxygenase and its redox partner in STX biosynthesis, was confirmed. These results support that 2 is a possible biosynthetic precursor of STX, and that ring and side-chain hydroxylations proceed after cyclization.

An On-Farm Workflow for Predictive Management of Paralytic Shellfish Toxin-Producing Harmful Algal Blooms for the Aquaculture Industry.

Paralytic shellfish toxins (PSTs) produced by marine dinoflagellates significantly impact shellfish industries worldwide. Early detection on-farm and with minimal training would allow additional time for management decisions to minimize economic losses. Here, we describe and test a standardized workflow based on the detection of sxtA4, an initial gene in the biosynthesis of PSTs. The workflow is simple and inexpensive and does not require a specialized laboratory. It consists of (1) water collection and filtration using a custom gravity sampler, (2) buffer selection for sample preservation and cell lysis for DNA, and (3) an assay based on a region of sxtA, DinoDtec lyophilized quantitative polymerase chain reaction (qPCR) assay. Water samples spiked with Alexandrium catenella showed a cell recovery of >90% when compared to light microscopy counts. The performance of the lysis method (90.3% efficient), Longmire's buffer, and the DinoDtec qPCR assay (tested across a range of Alexandrium species (90.7-106.9% efficiency; r2 > 0.99)) was found to be specific, sensitive, and efficient. We tested the application of this workflow weekly from May 2016 to 30th October 2017 to compare the relationship between sxtA4 copies L-1 in seawater and PSTs in mussel tissue (Mytilus galloprovincialis) on-farm and spatially (across multiple sites), effectively demonstrating an ∼2 week early warning of two A. catenella HABs (r = 0.95). Our tool provides an early, accurate, and efficient method for the identification of PST risk in shellfish aquaculture.

Carbamoylase-based impedimetric electronic tongue for rapid detection of paralytic shellfish toxins.

Phytotoxins produced by marine microalgae, such as paralytic shellfish toxins (PSTs), can accumulate in bivalve molluscs, representing a human health concern due to the life-threatening symptoms they cause. To avoid the commercialization of contaminated bivalves, monitoring programs were established in the EU. The purpose of this work is the implementation of a PST transforming enzyme-carbamoylase-in an impedimetric test for rapid simultaneous detection of several carbamate and N-sulfocarbamoyl PSTs. Carbamoylase hydrolyses carbamate and sulfocarbamoyl toxins, which may account for up to 90% of bivalve toxicity related to PSTs. Conformational changes of carbamoylase accompanying enzymatic reactions were probed by Fourier transform mid-infrared spectroscopy (FT-MIR) and electrochemical impedance spectroscopy (EIS). Furthermore, a combination of EIS with a metal electrode and a carbamoylase-based assay was employed to harness changes in the enzyme conformation and adsorption on the electrode surface during the enzymatic reaction as an analytical signal. After optimization of the working conditions, the developed impedimetric e-tongue could quantify N-sulfocarbamoyl toxins with a detection limit of 0.1 µM. The developed e-tongue allows the detection of these toxins at concentration levels observed in bivalves with PST toxicity close to the regulatory limit. The quantification of a sum of N-sulfocarbamoyl PSTs in naturally contaminated mussel extracts using the developed impedimetric e-tongue has been demonstrated.

Longitudinal study of paralytic shellfish toxins along Canada's coast.

Paralytic shellfish toxins (PST) in shellfish products have led to severe risks to human health. To monitor the risk, the Canadian Shellfish Sanitation Program has been collecting longitudinal PST measurements in blue mussel (Mytilus edulis) and soft-shell clam (Mya arenaria) samples in six coastal provinces of Canada. The spatial distributions of major temporal variation patterns were studied via Functional Principal Component Analysis. Seasonal increases in PST contamination were found to vary the most in terms of magnitude along the coastlines, which provides support for location-specific management of the time-sensitive PST contamination. In British Columbia, the first functional principal component (FPC1) indicated the variance among the magnitudes, while FPC2 indicated the seasonality of the PST levels. The temporal variations tended to be positively correlated with the abundance of dianoflagellates Alexandrium spp., and negatively with precipitation and inorganic nutrients. These findings indicate the underlying mechanism of PST variation in various geographical settings. In New Brunswick, Prince Edward, and Nova Scotia, the top FPCs indicated that the PST contamination differed mostly in the seasonal increase of the PST level during summer.

Differential Proteomic Analysis of Low-Dose Chronic Paralytic Shellfish Poisoning.

Shellfish poisoning is a common food poisoning. To comprehensively characterize proteome changes in the whole brain due to shellfish poisoning, Tandem mass tag (TMT)-based differential proteomic analysis was performed with a low-dose chronic shellfish poisoning model in mice. A total of 6798 proteins were confidently identified, among which 123 proteins showed significant changes (fold changes of >1.2 or <0.83, p < 0.05). In positive regulation of synaptic transmission, proteins assigned to a presynaptic membrane (e.g., Grik2) and synaptic transmission (e.g., Fmr1) changed. In addition, altered proteins in nervous system development were observed, suggesting that mice suffered nerve damage due to the nervous system being activated. Ion transport in model mice was demonstrated by a decrease in key enzymes (e.g., Kcnj11) in voltage-gated ion channel activity and solute carrier family (e.g., Slc38a3). Meanwhile, alterations in transferase activity proteins were observed. In conclusion, these modifications observed in brain proteins between the model and control mice provide valuable insights into understanding the functional mechanisms underlying shellfish poisoning.

Contamination Status and Risk Assessment of Paralytic Shellfish Toxins in Shellfish along the Coastal Areas of China.

Paralytic shellfish toxins (PSTs) are widely distributed in shellfish along the coast of China, causing a serious threat to consumer health; however, there is still a lack of large-scale systematic investigations and risk assessments. Herein, 641 shellfish samples were collected from March to November 2020, and the PSTs' toxicity was detected via liquid chromatography-tandem mass spectrometry. Furthermore, the contamination status and potential dietary risks of PSTs were discussed. PSTs were detected in 241 shellfish samples with a detection rate of 37.60%. The average PST toxicities in mussels and ark shells were considerably higher than those in other shellfish. The PSTs mainly included N-sulfonylcarbamoyl toxins (class C) and carbamoyl toxins (class GTX), and the highest PST toxicity was 546.09 µg STX eq. kg-1. The PST toxicity in spring was significantly higher than those in summer and autumn (p < 0.05). Hebei Province had the highest average PST toxicity in spring. An acute exposure assessment showed that consumers in Hebei Province had a higher dietary risk, with mussels posing a significantly higher dietary risk to consumers. This research provides reference for the green and sustainable development of the shellfish industry and the establishment of a shellfish toxin prevention and control system.

Paralytic shellfish toxins producing dinoflagellates cause dysbacteriosis in scallop gut microbial biofilms.

Filter-feeding bivalves could accumulate paralytic shellfish toxins (PSTs) produced by harmful dinoflagellates through diet. Despite that bivalves are resistant to these neurotoxins due to possessing PST-resistant sodium channel, exposure to PSTs-producing dinoflagellates impair bivalve survival. We hypothesized that ingesting PSTs-producing dinoflagellates may influence the gut microbiota, and then the health of bivalves. To test this idea, we compared the gut microbiota of the scallop Patinopecten yessoensis, after feeding with PST-producing or non-toxic dinoflagellates. Exposure to PSTs-producing dinoflagellates resulted in a decline of gut microbial diversity and a disturbance of community structure, accompanied by a significant increase in the abundance and richness of pathogenic bacteria, represented by Vibrio. Moreover, network analysis demonstrated extensive positive correlations between pathogenic bacteria abundances and PSTs concentrations in the digestive glands of the scallops. Furthermore, isolation of a dominant Vibrio strain and its genomic analysis revealed a variety of virulence factors, including the tolC outer membrane exporter, which were expressed in the gut microbiota. Finally, the infection experiment demonstrated scallop mortality caused by the isolated Vibrio strain; further, the pathogenicity of this Vibrio strain was attenuated by a mutation in the tolC gene. Together, these findings demonstrated that the PSTs may affect gut microbiota via direct and taxa-specific interactions with opportunistic pathogens, which proliferate after transition from seawater to the gut environment. The present study has revealed novel mechanisms towards deciphering the puzzles in environmental disturbances-caused death of an important aquaculture species.

Enhancing Lower Eyelid Suspension Outcomes Through Pre-surgical Facial Nerve Reanimation: A Comparative Study.

BACKGROUND: Lower eyelid suspension, a common therapeutic procedure for facial paralysis-induced eyelid retraction, faces challenges due to high recurrence in patients lacking facial muscle function and impedes wider adoption. This research aims to explore the potential effects of restoring orbicularis oculi muscle tension through facial nerve reanimation prior to lower eyelid suspension and to define the indications for lower eyelid suspension. METHODS: The study encompassed 32 individuals with complete facial paralysis, segmented into group A (reanimation group) and group B (non-reanimation group), based on whether the orbicularis oculi muscle's tension was restored through facial nerve reconstruction prior to lower eyelid suspension. Subjective assessments of eyelid closure (the inter-eyelid gap upon gentle closure) and objective methods measures of scleral show (the distance from the pupil's center to the lower eyelid margin, MRD2) were used to provide a comprehensive analysis of long-term effectiveness. RESULTS: The group A exhibited significantly greater long-term improvement in lagophthalmos and lower eyelid ectropion. The alterations in MRD2 measured 2.66 ± 0.27 mm in the group A versus 2.08 ± 0.53 mm in the group B, denoting a statistically significant variance (p < 0.001). Moreover, while the ratio of MRD2 preoperative 6 months postoperative revealed no significant difference between groups, a significant difference emerged in 12 months postoperative (group A: 1.02 ± 0.21; group B: 1.18 ± 0.24; p < 0.05), with the values in group A closer to 1, indicative of enhanced symmetry. CONCLUSIONS: Restoring the tension in the orbicularis oculi muscle through facial nerve reconstruction prior to palmaris longus tendon sling could effectively sustain long-term outcomes of lower eyelid retraction correction and reduce the recurrence rate. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Detection of paralytic shellfish toxins by near-infrared spectroscopy based on a near-Bayesian SVM classifier with unequal misclassification costs.

BACKGROUND: Paralytic shellfish poisoning caused by human consumption of shellfish fed on toxic algae is a public health hazard. It is essential to implement shellfish monitoring programs to minimize the possibility of shellfish contaminated by paralytic shellfish toxins (PST) reaching the marketplace. RESULTS: This paper proposes a rapid detection method for PST in mussels using near-infrared spectroscopy (NIRS) technology. Spectral data in the wavelength range of 950-1700 nm for PST-contaminated and non-contaminated mussel samples were used to build the detection model. Near-Bayesian support vector machines (NBSVM) with unequal misclassification costs (u-NBSVM) were applied to solve a classification problem arising from the fact that the quantity of non-contaminated mussels was far less than that of PST-contaminated mussels in practice. The u-NBSVM model performed adequately on imbalanced datasets by combining unequal misclassification costs and decision boundary shifts. The detection performance of the u-NBSVM did not decline as the number of PST samples decreased due to adjustments to the misclassification costs. When the number of PST samples was 20, the G-mean and accuracy reached 0.9898 and 0.9944, respectively. CONCLUSION: Compared with the traditional support vector machines (SVMs) and the NBSVM, the u-NBSVM model achieved better detection performance. The results of this study indicate that NIRS technology combined with the u-NBSVM model can be used for rapid and non-destructive PST detection in mussels. © 2023 Society of Chemical Industry.

Frontalis muscle flap eyelid reanimation technique in adults with severe ptosis or apraxia of eyelid opening.

PURPOSE: Assessment of the frontalis muscle flap eyelid reanimation surgical technique for adults with severe ptosis and apraxia of eyelid opening. METHODS: A retrospective case series of 30 eyes with severe ptosis or apraxia of eyelid opening. Outcomes were assessed for margin to reflex distance 1 (MRD1), lagophthalmos, complications, and need for subsequent surgical intervention. A paired t-test was used to compare preoperative and postoperative scores of a quality-of-life questionnaire. RESULTS: Thirty eyes of 19 patients underwent surgery, 16 (53%) with combined frontalis + levator-Muller muscle flap and 14 (46%) with frontalis muscle flap alone. There were 14 female and 5 male patients, with an average age of 55 years (range, 18-76). Mean preoperative MRD1 was -0.6 mm (range, -5 to 2) with mean levator excursion of 7.1 mm. Seventeen eyes had a myogenic etiology, five had a paralytic etiology, six had blepharospasm with apraxia of lid opening, and two had a neurodegenerative etiology. Nineteen eyes (63%) had previously undergone ptosis repair. Mean postoperative MRD1 was 2.5 mm (range, 0.5 to 5) at mean follow-up of 63.3 days. There were no serious surgical complications; minor complications included ocular surface keratopathy and one patient who required surgical revision. Results of the QOL questionnaire indicated significant improvement in vision-related symptoms postoperatively (p = 0.02). CONCLUSIONS: Use of the frontalis muscle flap eyelid reanimation technique, with or without a levator-Muller retractor muscle flap, was very effective in this case series and provided good upper eyelid position with acceptable corneal protection and high patient satisfaction.

Paralytic Shellfish Toxins in the Gastropod Concholepas concholepas: Variability, Toxin Profiles and Mechanisms for Toxicity Reduction.

Harmful algal blooms of toxin-producing microalgae are recurrent in southern Chile. Paralytic shellfish poisoning (PSP) outbreaks pose the main threat to public health and the fishing industry in the Patagonian fjords. This study aims to increase understanding of the individual and spatial variability of PSP toxicity in the foot of Concholepas concholepas, Chile's most valuable commercial benthic invertebrate species, extracted from the Guaitecas Archipelago in Chilean Patagonia. The objective is to determine the effect of pigment removal and freezing during the detoxification process. A total of 150 specimens (≥90 mm length) were collected from this area. The live specimens were transferred to a processing plant, where they were measured and gutted, the foot was divided into two equal parts, and pigment was manually removed from one of these parts. The PSP toxicity of each foot (edible tissue) was determined by mouse bioassay (MBA) and high-performance liquid chromatography with fluorescence detection and postcolumn oxidation (HPLC-FLD PCOX). The individual toxicity per loco, as the species is known locally, varied from <30 to 146 µg STX diHCL eq 100 g−1 (CV = 43.83%) and from 5.96 to 216.3 µg STX diHCL eq 100 g−1 (CV = 34.63%), using MBA and HPLC, respectively. A generalized linear model showed a negative relation between individual weight and toxicity. The toxicological profile showed a dominance of STX (>95%), neoSTX and GTX2. The removal of pigment produced a reduction in PSP toxicity of up to 90% and could represent a good detoxification tool moving forward. The freezing process in the muscle with pigment did not produce a clear pattern. There is a significant reduction (p < 0.05) of PSP toxicity via PCOX but not MBA. Furthermore, the study discusses possible management and commercialization implications of the findings regarding small-scale fisheries.

Toxicogenomic Effects of Dissolved Saxitoxin on the Early Life Stages of the Longfin Yellowtail (Seriola rivoliana).

Harmful algal blooms (HABs) can produce a variety of noxious effects and, in some cases, the massive mortality of wild and farmed marine organisms. Some HAB species produce toxins that are released into seawater or transferred via food webs (particulate toxin fraction). The objective of the present study was to identify the toxicological effects of subacute exposure to saxitoxin (STX) during embryonic and early larval stages in Seriola rivoliana. Eggs were exposed to dissolved 19 STX (100 µg L-1). The toxic effects of STX were evaluated via the hatching percentage, the activity of three enzymes (protein and alkaline phosphatases and peroxidase), and the expression of four genes (HSF2, Nav1.4b, PPRC1, and DUSP8). A low hatching percentage (less than 5%) was observed in 44 hpf (hours post fertilization) embryos exposed to STX compared to 71% in the unexposed control. At this STX concentration, no oxidative stress in the embryos was evident. However, STX induced the expression of the NaV1.4 channel α-subunit (NaV1.4b), which is the primary target of this toxin. Our results revealed the overexpression of all four candidate genes in STX-intoxicated lecithotrophic larvae, reflecting the activation of diverse cellular processes involved in stress responses (HSF2), lipid metabolism (PPRC1), and MAP kinase signaling pathways associated with cell proliferation and differentiation (DUSP8). The effects of STX were more pronounced in young larvae than in embryos, indicating a stage-specific sensitivity to the toxin.

Degradation of paralytic shellfish toxins during flocculation of Alexandrium pacificum by an oxidized modified clay: A laboratory experiment.

Paralytic shellfish toxins (PSTs), produced by Alexandrium pacificum in the marine environment, are a group of potent neurotoxins which specifically block voltage-gated sodium channels in excitable cells. During the toxigenic A. pacificum blooms outbreaks, PSTs can be accumulated through the food chain and finally enter the human body, posing a significant threat to human health and safety. This study experimented with a novel type of oxidized modified clay, potassium peroxymonosulfate modified clay (PMPS-MC), which could remove A. pacificum cells as well as reduce intracellular and extracellular PSTs toxicity rapidly. For the extracellular PSTs, its content decreased to below the detection limit rapidly through oxidative degradation within 15 min of 10 mg/L PMPS-MC treatment. Whereafter, although the residual cells in water column and some viable cells in flocculated sediment continued to secrete toxins, the extracellular PSTs content and toxicity in the PMPS-MC treatment groups remained significantly lower than those in the control group. For the intracellular PSTs, PMPS-MC might induce the transformation of more toxic GTX1&4 to less toxic GTX2&3 and C1&2, resulting in intracellular PSTs toxicity reduced within 15 min. In addition, intracellular PSTs content and toxicity in the PMPS-MC treatment groups were consistently lower than the control group within 48 h, possibly by inhibiting the A. pacificum cells growth. These results will provide a scientific basis for the field application of modified clay to control A. pacificum blooms.

Anastomotic Leak Rate and Prolonged Postoperative Paralytic Ileus in Patients Undergoing Laparoscopic Surgery for Colo-Rectal Cancer After Placement of No-Coil Endoanal Tube.

BACKGROUND: Colorectal cancer (CRC) is the second most common gastrointestinal tumor in men and the third in women. Left-hemicolectomy (LC) and low anterior resection (LAR) are considered the gold standard curative treatment. In this retrospective study, we evaluated the presence or absence of post-operative complications, in all patients who underwent Video-laparoscopic (VLS) LAR/LC with No Coil trans-anal tube positioning, and compared the data with the current literature on the topic. METHODS: Thirty-nine patients diagnosed with CRC of the descending colon, splenic flexure, sigma, and rectum were recruited. LC was performed for sigmoid and descending colon cancers, while LAR was applied for tumors of the upper two-thirds of the rectum. The No Coil trans-anal tube (SapiMed Spa, Alessandria, Italy) was placed in all patients of the study at the end of surgical treatment. RESULTS: Eighteen patients received a LAR-VLS (46%) and 21 patients received a LC-VLS (54%). The average length of hospital stay after surgery was 7 days. PPOI occurred in only one in 39 patients (2.6%) who had undergone LAR-VLS. As for complications, in no patient of the study did AL (0%) occur. CONCLUSION: In patients undergoing LAR-VLS and LC-VLS, we performed colorectal anastomosis and in the same surgical operation we introduced the No-Coil device. Although this is a preliminary study and subject to further investigation, we believe that the No Coil tube positioning may reduce the time of presence of first flatus and feces and the risk of AL.

Ocular involvement in facial nerve paralysis: risk factors for severe visual impairment and ocular surface exposure in 1870 patients.

PURPOSE: To identify the risk factors associated with the development of ocular surface exposure and severe visual impairment (SVI) in patients with facial nerve palsy (FNP). METHODS: Ocular data of all consecutive FNP patients (N = 1870) presenting to an eye-care network over the past 10 years were reviewed. Risk factors associated with SVI (best-corrected visual acuity <20/200) and ocular surface exposure at presentation were evaluated using multivariate analysis and odds ratios (OR). RESULTS: The prevalence of SVI was 15%, and 47% had ocular surface exposure at the first presentation. The presence of corneal scar (28% vs. 10.2%, p < .001; OR 3.05), corneal ulcer (12.9% vs. 2.3%, p < .001; OR 4.67), older age at presentation (p < .001; OR 1.02), >10 mm lagophthalmos (p < .001; OR 8.7), male sex, and duration of FNP (p = .021; OR 1) were independent risk factors for developing SVI. Of the 893 eyes with ocular surface exposure, 75 (3.9%) had a corneal ulcer, and 11 (0.6%) were perforated, with the rest having epithelial defects and punctate keratopathy. Patients with neoplastic etiology (15.9% vs. 5.7%; p < .001; OR 2.39), lagophthalmos (49% vs. 29.7%; p < .001; OR 2.25) and poor Bell's phenomenon (9.4% vs. 4.2%; p = .005; OR 1.8) had twofold risk for developing ocular surface exposure. CONCLUSION: Eyes with lagophthalmos, poor Bell's phenomenon, and FNP of neoplastic etiology have a higher risk of developing ocular surface exposure. Male sex, increasing age, longer duration of FNP, and >10 mm lagophthalmos are associated with SVI in FNP patients; hence, early and timely intervention is necessary.

VITAMIN D STATUS IN CHILDREN WITH PARALITIC SYNDROMS.

OBJECTIVE: The aim: Determination of serum 25(OH)D in the children with paralytic syndromes and its distribution depending on age, sex, taking anticonvulsant drugs, nutritional status for a period of one year (autumn-spring) of one center. PATIENTS AND METHODS: Materials and methods: There were recruited of 77 children with paralytic syndromes and 73 health children for the same period aged from 1 till 18 years. The study included a scrutiny of medical history and analysis of medical documents, assessment of motor dysfunction by GMFCS, and nutritional status. RESULTS: Results: Among children with paralytic syndromes there were spastic tetraparesis 59.7%, malnutrition 92%, IV-V level of gross motor disfunction 80.5%, antiseizure medications 59.7% and cognitive impairment 77.9%. The variation of serum 25(OH)D is from 6.1 to 76.7 ng/mL with median 18.3 ng/mL in healthy children. The variation of serum 25(OH)D is from 2.2 to 83.0 ng/mL with median 14.8 ng/mL in children with paralytic syndromes (p=0.0103). Vitamin status among them is the following: insufficiency (21-29 ng/mL)-28.7% vs 16.8%; deficiency (<20 ng/mL)-56.1 vs 72.2% (p=0.0300). The 25.9% children with paralytic syndromes and those who have deficiency demonstrate severe deficiency (<10 ng/mL) compare 10.9% in healthy children (p=0.00189). There is a tendency to decrease of serum 25(OH)D in children with paralytic syndrome older 7 years. CONCLUSION: Conclusions: We failed to record a significant difference in the 25(ОН)D between males and females, between different level of GMFCS, and anticonvulsants using. Deficiency of vitamin D in 2.25 times higher in children with paralytic syndromes and severe malnutrition. Additional researches with specific items are need in perspective.

Atracurium Versus Cisatracurium in the Treatment of Acute Respiratory Distress Syndrome.

Background: Neuromuscular blocking agents are one of the few medication classes that have demonstrated a clinical benefit in patients with severe acute respiratory distress syndrome (ARDS). However, most literature utilized cisatracurium, and utilization of atracurium is limited to 1 small study. Objective: The purpose of this study was to provide further evidence comparing the safety and efficacy of atracurium versus cisatracurium for the treatment of ARDS. Methods: This multicenter, retrospective, observational cohort noninferiority study was conducted at 3 hospitals within a tertiary health care system. We included subjects diagnosed with ARDS who received either atracurium or cisatracurium for at least 12 hours. The primary outcome measured the change in PaO2/FiO2 (P/F) ratio from baseline to 48 hours after initiation. Results: Baseline characteristics were similar between groups except for a higher median age and a higher proportion of subjects who were COVID-positive in the atracurium group. There were also some noted differences in the baseline P/F ratios. In a multivariable model adjusting for baseline characteristics, the change in the P/F ratio for atracurium was noninferior to cisatracurium at 24, 48, and 72 hours. A significant cost reduction, measured as cost per patient per day, was seen with the use of atracurium ($14.81-$25.16 vs $33.86-$41.91). Conclusion: Atracurium appears to be a safe and cheaper alternative agent in the management of ARDS.

The effect of iron on Chilean Alexandrium catenella growth and paralytic shellfish toxin production as related to algal blooms.

The dinoflagellate Alexandrium catenella is a well-known paralytic shellfish toxin producer that forms harmful algal blooms (HABs) worldwide. Blooms of this species have repeatedly brought severe ecological and economic impacts to Chile, especially in the southern region, where the shellfish and salmon industries are world-famous. The mechanisms of such HABs have been intensively studied but are still unclear. Nutrient overloading is one of the often-discussed drivers for HABs. The present study used the A. catenella strain isolated from southern Chile to investigate how iron conditions could affect their growth and toxin production as related to HAB. Our results showed that an optimum concentration of iron was pivotal for proper A. catenella growth. Thus, while excess iron exerted a toxic effect, low iron media led to iron insufficiency and growth inhibition. In addition, the study shows that the degree of paralytic shellfish toxin production by A. catenella varied depending on the iron concentration in the culture media. The A. catenella strain from southern Chile produced GTX1-4 exclusively in the fmol cell-1 scale. Based on these findings, we suggest that including iron and paralytic shellfish toxin measurements in the fields can improve the current HAB monitoring and contribute to an understanding of A. catenella bloom dynamics in Chile.

Variations in the toxicity and condition index of five bivalve species throughout a red tide event caused by Alexandrium catenella: A field study.

Harmful red tides in China have caused paralytic shellfish toxins (PSTs) pollution and led to severe socioeconomic effects in shellfish aquaculture. Although shellfish can survive harmful algal blooms, the effects on their Condition Index (CI) have been underestimated. This study sought to evaluate the effects of the profiles and levels of paralytic shellfish toxins on variations in the CI in bivalves under natural blooming conditions. We observed clear soft tissue lesions to varying degrees except in Mytilus galloprovincialis after toxin exposure. Among the five species of shellfish exposed in situ, only M. galloprovincialis accumulated PSTs content above the maximum permitted level (800 µg STX di-HCl eq./kg). The highest toxin content in all sample tissues was observed in Patinopecten yessoensis. Significant interspecies differences in PSTs accumulation among the five bivalve species were observed in the hepatopancreas. A total of nine PSTs components and four new C-11 hydroxyl metabolites (so-called M-toxins) toxins were detected, and detoxification diversity was observed among bivalves. We observed a higher proportion of M-toxin in early stages, and the proportions changed only slightly over time in M. galloprovincialis and Magallana gigas, thus accounting for the significantly higher metabolism rate. Notably, the CI in M. gigas and Argopecten irradians was positively correlated with lowest toxin accumulation of PSTs content, but significantly inhibited. In conclusion, our results revealed a significant inhibitory effect on the CI in shellfish, in a species specific manner, with distinct levels of inhibition correlated with different toxin metabolites. Our study revealed the toxin content of different bivalves exposed to a natural red tide environment and the consequent effects on growth, thus building a foundation for research on the mechanisms underlying the effects of PSTs on growth. These data establish the ecological and economic significance of the effects of harmful algal blooms on bivalves.

Reversal of Feed Intolerance by Prokinetics Improves Survival in Critically Ill Cirrhosis Patients.

BACKGROUND AND AIMS: Feed intolerance (FI) is common in cirrhosis patients in intensive care units (ICU). Prokinetics are the first line treatment for FI but their efficacy and safety in critically ill patient with cirrhosis is unknown. We evaluated the role of prokinetics in reversal of FI and clinical outcomes. METHODS: Consecutive patients admitted in ICU developing new-onset FI, were randomized to receive either intravenous metoclopramide (Gr.A, n = 28), erythromycin (Gr.B, n = 27) or placebo (Gr.C, n = 28). FI was defined with the presence of 3 of 5 variables- absence of bowel sounds, gastric residual volume ≥ 500 ml, vomiting, diarrhoea and bowel distension. Primary end-point was complete resolution of FI (≥ 3 variables resolved) within 24-h and secondary end-points included resolution within 72-h and survival at 7-days. RESULTS: Of the 1030 ICU patients, 201 (19.5%) developed FI and 83 patients were randomized. Baseline parameters between the groups were comparable. Complete resolution at 24-h was higher in Gr.A (7.14%) and B (22.2%) than C (0%, p = 0.017). Overall, 58 (69.9%) patients achieved resolution within 72 h, more with metoclopramide (n = 24, 85.7%) and erythromycin (n = 25, 92.6%) than with placebo (n = 9, 32.1%, p < 0.001). The 7-day survival was better in patients who achieved resolution within 72-h (65.5 vs. 36%, p = 0.011) than non-responders. High lactate (OR-3.32, CI-1.45-7.70, p = 0.005), shock at baseline (OR-6.34, CI-1.67-24.1, p = 0.007) and resolution of FI within 72 h (OR-0.11, CI, 0.03-0.51, p = 0.04) predicted 7-day mortality. CONCLUSIONS: FI is common in critically-ill cirrhosis patients and non-resolution carries high mortality. Early recognition and treatment with prokinetics is recommended to improve short-term survival.

Gastrointestinal dysmotility is common in cirrhosis and higher incidence in critically ill patients. Promotility drugs are the first line of medication especially in ICU patients. In our study, we found that feed intolerance is present in nearly one in five critically ill cirrhosis and is associated with higher mortality. Patients who achieve resolution had an improved short-term survival. Prokinetic medications are safe in critically ill cirrhosis and help in early resolution of feed intolerance. Feed intolerance in critically ill cirrhosis should be recognized as an organ dysfunction and approaches for prevention and early diagnosis of feed intolerance could help in improving the outcomes in critical illness.