Concentrations In Muscle Tissue Research Articles

Effect of Body Size on Plasma and Tissue Pharmacokinetics of Danofloxacin in Rainbow Trout (Oncorhynchus mykiss)

Danofloxacin is a fluoroquinolone antibiotic approved for use in fish. It can be used for bacterial infections in fish of all body sizes. However, physiological differences in fish depending on size may change the pharmacokinetics of danofloxacin and therefore its therapeutic efficacy. In this study, the change in the pharmacokinetics of danofloxacin in rainbow trout of various body sizes was revealed for the first time. The objective of this investigation was to compare the plasma and tissue pharmacokinetics of danofloxacin in rainbow trout of different body sizes. The study was conducted at 14 ± 0.5 °C in fish of small, medium, and large body size and danofloxacin was administered orally at a dose of 10 mg/kg. Concentrations of this antimicrobial in tissues and plasma were quantified by high performance liquid chromatography with ultraviolet detector. The plasma elimination half-life (t1/2ʎz), volume of distribution (Vdarea/F), total clearance (CL/F), peak concentration (Cmax), and area under the plasma concentration–time curve (AUC0–last) were 27.42 h, 4.65 L/kg, 0.12 L/h/kg, 2.53 µg/mL, and 82.46 h·µg/mL, respectively. Plasma t1/2ʎz, AUC0–last and Cmax increased concomitantly with trout growth, whereas CL/F and Vdarea/F decreased. Concentrations in liver, kidney, and muscle tissues were higher than in plasma. Cmax and AUC0–last were significantly higher in large sizes compared to small and medium sizes in all tissues. The scaling factor in small, medium, and large fish was 1.0 for bacteria with MIC thresholds of 0.57, 0.79, and 1.01 µg/mL, respectively. These results show that therapeutic efficacy increases with body size. However, since increases in danofloxacin concentration in tissues of large fish may affect withdrawal time, attention should be paid to the risk of tissue residue.

Effect of Dietary Digestible Protein Levels on Muscle Growth and Oxidative Stress in Amazonian Pintado (Pseudoplatystoma reticulatum × Leiarius marmoratus).

This study aimed to evaluate the effects of dietary digestible protein levels on the growth dynamics and oxidative stress status of white muscle fibers in Amazonian Pintado (Pseudoplatystoma reticulatum × Leiarius marmoratus). Four hundred and fifty-five juveniles of Amazonian Pintado were fed diets containing varying digestible protein levels (225, 250, 275, 300, 325, 350, or 375 g kg-1) for 75 days. At the end of the experiment, the fish were fasted for 24 h, anesthetized, and euthanized to obtain muscle samples. The linear and quadratic effects of dietary digestible protein levels on white muscle fiber diameter, metabolite concentrations, and oxidative stress were assessed. The results revealed that increasing dietary digestible protein levels linearly raised the concentrations of free amino acids and total proteins in muscle tissue but also led to elevated levels of TBARS, indicating increased oxidative stress. Notably, the average area of muscle fibers with a cell area greater than 1133 µm2 decreased, reflecting restricted muscle hypertrophy, whereas glycogen and glucose levels also declined. These findings suggest that although high dietary digestible protein enhances protein and free amino acid concentrations in muscle tissue, it may compromise muscle hypertrophy and increase oxidative damage in Amazonian Pintado, underscoring the complexity of optimizing diet formulation.

Relationship of Size and Mass Characteristics, Indicators of Metabolism and Mercury Concentration in Muscle Tissue of Freshwater Fish from Tropical Vietnam

Relationship of Size and Mass Characteristics, Indicators of Metabolism and Mercury Concentration in Muscle Tissue of Freshwater Fish from Tropical Vietnam

Accumulation of Per- and Polyfluoroalkyl Substances (PFAS) in Coastal Sharks from Contrasting Marine Environments: The New York Bight and The Bahamas.

Per- and polyfluoroalkyl substances (PFAS) enter the marine food web, accumulate in organisms, and potentially have adverse effects on predators and consumers of seafood. However, evaluations of PFAS in meso-to-apex predators, like sharks, are scarce. This study investigated PFAS occurrence in five shark species from two marine ecosystems with contrasting relative human population densities, the New York Bight (NYB) and the coastal waters of The Bahamas archipelago. The total detected PFAS (∑PFAS) concentrations in muscle tissue ranged from 1.10 to 58.5 ng g-1 wet weight, and perfluorocarboxylic acids (PFCAs) were dominant. Fewer PFAS were detected in Caribbean reef sharks (Carcharhinus perezi) from The Bahamas, and concentrations of those detected were, on average, ∼79% lower than in the NYB sharks. In the NYB, ∑PFAS concentrations followed: common thresher (Alopias vulpinus) > shortfin mako (Isurus oxyrinchus) > sandbar (Carcharhinus plumbeus) > smooth dogfish (Mustelus canis). PFAS precursors/intermediates, such as 2H,2H,3H,3H-perfluorodecanoic acid and perfluorooctanesulfonamide, were only detected in the NYB sharks, suggesting higher ambient concentrations and diversity of PFAS sources in this region. Ultralong-chain PFAS (C ≥ 10) were positively correlated with nitrogen isotope values (δ15N) and total mercury in some species. Our results provide some of the first baseline information on PFAS concentrations in shark species from the northwest Atlantic Ocean, and correlations between PFAS, stable isotopes, and mercury further contextualize the drivers of PFAS occurrence.

Penetration of Antibiotics into Subcutaneous and Intramuscular Interstitial Fluid: A Meta-Analysis of Microdialysis Studies in Adults.

The interstitial fluid of tissues is the effect site for antibiotics targeting extracellular pathogens. Microdialysis studies investigating these concentrations in muscle and subcutaneous tissue have reported notable variability in tissue penetration. This study aimed to comprehensively summarise the existing data on interstitial fluid penetration in these tissues and to identify potential factors influencing antibiotic distribution. A literature review was conducted, focusing on subcutaneous and intramuscular microdialysis studies of antibiotics in both adult healthy volunteers and patients. Random-effect meta-analyses were used to aggregate effect size estimates of tissue penetration. The primary parameter of interest was the unbound penetration ratio, which represents the ratio of the area under the concentration-time curve in interstitial fluid relative to the area under the concentration-time curve in plasma, using unbound concentrations. In total, 52 reports were incorporated into this analysis. The unbound antibiotic exposure in the interstitial fluid of healthy volunteers was, on average, 22% lower than in plasma. The unbound penetration ratio values were higher after multiple dosing but did not significantly differ between muscle and subcutaneous tissue. Unbound penetration ratio values were lower for acids and bases compared with neutral antibiotics. Neither the molecular weight nor the logP of the antibiotics accounted for the variations in the unbound penetration ratio. Obesity was associated with lower interstitial fluid penetration. Conditions such as sepsis, tissue inflammation and tissue ischaemia were not significantly associated with altered interstitial fluid penetration. This study highlights the variability and generally lower exposure of unbound antibiotics in the subcutaneous and intramuscular interstitial fluid compared with exposure in plasma. Future research should focus on understanding the therapeutic relevance of these differences and identify key covariates that may influence them.

Heavy metal concentrations in fishes from Zakrzówek Reservoir and the Vistula River near Kraków: Human risk assessment

Abstract The aim of this study was to compare tissue concentrations of heavy metals (copper (Cu), manganese (Mn), iron (Fe), nickel (Ni), zinc (Zn)) in roach (Rutilus rutilus (L.)), chub (Squalius cephalus (L.)), and bleak (Alburnus alburnus (L.)) from two locations on the Vistula River upstream from Kraków and Zakrzówek Reservoir, a former limestone quarry flooded over 30 years ago that is located close to the center of Kraków. The findings showed that heavy metal concentrations in fishes from the Vistula River upstream from Kraków were higher compared to those in fishes from Zakrzówek Reservoir. The highest heavy metal concentrations were found in hard tissues, such as bone and scales, and the lowest was in muscle tissue. Metal pollution index (MPI), estimated daily intake (EDI), target hazard quotient (THQ), and hazard index (HI) analyses showed no significant non-carcinogenic risk to human health from the consumption of the muscle meat of the fishes analyzed. Cancer risk (CR) values, calculated based on maximum Ni concentrations in fish muscle tissue, did not exceed the upper limit of the acceptable cancer risk range. The findings show that the assessment of heavy metal contamination of fishes should be continued and extended to include other water bodies used for fishing and other xenobiotics that accumulate in fishes and may pose risks to human health.

Mercury bioaccumulation and trophic transfer in Pacific Saury from the North Pacific Ocean

This study investigates mercury (Hg) dynamics in Pacific Saury (Cololabis saira) across the North Pacific Ocean, specifically off East Japan in 2018. Saury traits vary with total mercury (THg) concentrations in muscle tissues ranging from 0.017 to 0.082 μg g−1 w. w., averaging of 0.042 (n = 46). A positive correlation between THg and saury length (Knob length, 270–319 mm) indicates increased Hg concentration with size. Stable isotopic tracers suggest Pacific Euphausiids (Krill) are significant contributors to the saury diet (>70% of total). Significant correlations between logarithm THg concentration (Log THg) and δ15N (‰) (R2 = 0.70) demonstrate Hg trophic biomagnification, with regional variations. Comparative analysis between the eastern (ENPO) and western North Pacific Ocean (WNPO) indicates differences, with WNPO saury exhibiting lower δ15N values and higher THg levels than ENPO saury. This suggests that the WNPO, located near East Asia, the world's largest Hg emitter, experiences elevated Hg levels in seawater due to anthropogenic release. Overall, this study advances understanding of Pacific Saury's ecological interactions and Hg bioaccumulations, emphasizing the importance of species-specific behaviors and regional influences in ecological studies.

Intraspecific Variation in Mercury Contamination of Alligator Snapping Turtles (Macrochelys temminckii).

Macrochelys temminckii (alligator snapping turtle) is an aquatic turtle endemic to the southeastern United States that was proposed for listing under the Endangered Species Act in 2021. In the present study we analyzed total mercury (THg) concentrations in skeletal muscle, tail clips, and nail tissue of 93 M. temminckii sampled from 14 waterbodies in eastern Texas (USA). Our objectives were to assess (1) the degree of correlation between internal tissue (skeletal muscle and tail clip samples) and keratin (nail samples), (2) the influence of ecological factors (turtle size and waterbody/sampling site) on THg concentrations, and (3) whether THg concentrations were high enough to pose a risk to human consumers. The mean (±SE) THg concentrations of muscle and nail were 1.16 ± 0.08 μg/g dry weight and 4.21 ± 0.24 μg/g dry weight, respectively, and THg concentrations were highly dependent on the sampling site. The THg concentrations of nails were correlated with muscle concentrations (R2 = 0.56, p < 0.001). The effect of body size on THg concentrations varied by sampling site, indicating that size is not a good predictor of Hg concentration across sites. Finally, THg concentrations in M. temminckii of eastern Texas were high enough to pose a potential risk to human health based on US Environmental Protection Agency dietary guidelines. Environ Toxicol Chem 2024;43:1903-1913. © 2024 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Mercury biomagnification in the food chain of a piscivorous turtle species (Testudines: Chelidae: Chelus fimbriata) in the Central Amazon, Brazil.

Due to their natural history and ecological attributes, turtles are excellent organisms for studies of heavy metal contamination. Turtles have a large geographical distribution, occupy different aquatic habitats, and occupy various trophic levels. The present study investigated mercury bioaccumulation in the carnivorous chelonian Chelus fimbriata (Matamata turtle) and Hg biomagnification in relation to its aquatic food chain in the middle Rio Negro, AM-Brazil. Tissue samples of muscle, carapace and claws were collected from 26 C. fimbriata individuals, as well as collections of autotrophic energy sources found in the turtle's aquatic habitat area. The samples were collected in February-March/2014 and analyzed for THg concentrations and carbon (δ13C) and nitrogen (δ15N) stable isotopes. The highest THg levels were found in claws (3780 ng.g-1), carapace (3622 ng.g-1) and muscle (403 ng.g-1), which were found to be significantly different [F(2.73) = 49.02 p < 0.01]. However, THg concentrations in muscle tissue were below the consumption threshold indicated by the WHO and Brazilian Health Ministry. The average δ13C and δ15N values in Matamata samples were -31.7‰ and 11.9‰, respectively. The principal energy source sustaining the food chain of C. fimbriata was found to be terrestrial shrubs, with smaller contributions from emergent aquatic herbaceous plants and algae, while δ15N values showed its trophic position to be two levels above the autotrophic energy sources. There was a positive correlation between THg and turtle size, while a significant relationship was found between THg and δ15N, showing strong biomagnification in the food chain of C. fimbriata: y = 0.21x + 0.46; r2 = 0.45; p < 0.001, for which the slope presented a value of 0.21.

Comparison of carbon, nitrogen, and oxygen stable isotope ratios and mercury concentrations in muscle tissues of five beaked whale species and sperm whales stranded in Hokkaido, Japan

ABSTRACT We studied δ 13C, δ 15N and δ 18O values, and total mercury (THg) concentrations in muscle samples from deep-sea predators – five beaked whale species and sperm whales – stranded along the coast of Hokkaido, in the north of Japan in 2010 and 2019. The δ 13C, δ 15N and δ 18O values, THg concentrations, and body length (BL) of Stejneger’s beaked whales were similar to those of Hubbs’ beaked whales, which belong to the same genus. In contrast, δ 13C values, THg concentrations, and BL of Sato’s beaked whales were markedly different from those of Baird’s beaked whales, which belong to the same genus. Stejneger’s and Hubbs’ beaked whales living around Hokkaido may compete in their ecological niches, whereas Sato’s and Baird’s beaked whales may segregate their ecological niches. Although Cuvier’s beaked whales and sperm whales belong to different genera and their BLs were significantly different, their δ 13C and δ 15N values were similar, probably because they can dive and stay in deeper waters than other beaked whale species. The δ 13C values in combined samples from all whales increased with increasing BL, probably owing to the larger whale species’ dietary preference for squid. The δ 13C values in combined samples from all whales were positively correlated with THg concentrations, whereas the δ 15N values in the combined samples were negatively correlated. The δ 18O values in combined samples from most whales tended to be positively correlated with THg concentrations. These correlations may be explained by a higher THg load from deep-sea feeding than from pelagic feeding and by a feeding shift towards lower trophic levels.

Comparing Nitric Oxide Generation Pathways using Dietary L-Arginine and Dietary Nitrate: A 15N tracer study in Wistar Rats

Mammals generate nitric oxide (NO) through two main pathways. In the direct production pathway, endogenous nitric oxide synthase (NOS) enzymes catalyze the reaction of L-arginine with oxygen, producing nitric oxide and citrulline. When oxygen accessibility is low, the reductive pathway supplies nitric oxide through the nitrate-nitrite-NO reduction cascade. Additional research is needed to understand whether the two NO generation pathways interact and what effects the two pathways have on the body and each other. We investigated how dietary supplementation of 15N-L-arginine (0.5 g/kg), 15N-nitrate (0.013 g/kg), or a combination of L-arginine and nitrate influences nitrate concentrations in plasma, skeletal muscle, and liver tissue from Wistar rats. We administered treatments via oral gavage. Two hours after treatment administration, we euthanized the rats and collected tissue samples. The nitrate concentrations were measured using chemiluminescence, and future mass spectrometry analysis for 15N/14N ratios will be performed. The calculated concentrations were compared between treatment groups using single factor analysis of variance. Firstly, we observed that nitrate administration significantly increased total nitrate levels in plasma, liver, and muscle tissues compared to the control group. Interestingly, L-arginine alone did not result in a significant rise in total nitrate concentrations. Notably, liver tissue from the L-arginine-treated group had slightly lower concentrations of nitrate than the control group. The combination of L-arginine and nitrate showed no statistically significant difference when compared with the nitrate-treated group in all three tissues. These results suggest that a bolus of L-arginine does not have a substantial short-term effect (within 2 hours after ingestion) on total nitrate concentrations in rat tissues. Future mass spectrometry analysis will indicate how the tissues handle acute ingestion of two different NO sources: L-arginine and nitrate. Further research must be performed for a more detailed understanding of the kinetics of arginine and nitrate, as well as for the effects of these dietary supplements on improving NO homeostasis. This work was supported by intramural NIDDK/NIH grant ZIA DK 025104-15 to Alan N. Schechter. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Changes in Carbon, Nitrogen, and Oxygen Stable Isotope Ratios and Mercury Concentrations in Killer Whales (Orcinus orca) during and after Lactation

The changes in the stable isotope ratios of carbon (δ13C), nitrogen (δ15N), oxygen (δ18O), and mercury (Hg) concentrations in muscle and liver tissues during and after lactation were studied in killer whales stranded along the coast of Hokkaido, in the northern area of Japan (n = 16). Calf muscles displayed δ13C- and δ15N-enriched peaks and a δ18O-depleted peak during lactation. The δ13C- and δ15N-enriched peaks appear to reflect the extensive nursing of 13C- and 15N-enriched milk and the onset of weaning, whereas the δ18O-depleted peak may be attributable to the extensive nursing of 18O-depleted milk and the onset of weaning. The δ13C and δ15N values tended to gradually increase after the weaning, whereas the δ18O values tended to decrease. The δ13C and δ15N levels in calves were similar between liver and muscle samples, whereas those in mature animals were higher in liver than in muscle samples. The isotopic turnover rates of C and N may be similar between the liver and muscle tissues in calves, which are rapidly growing animals. The Hg concentrations in muscle tissues were slightly higher in small calves than in large calves, probably due to the Hg transfer across placenta. The Hg concentrations in liver and muscle samples increased with increasing body length, and those in two liver samples from mature animals exceeded the high-risk threshold for marine mammal health effects (82 μg/wet g).

Integrative model-based comparison of target site-specific antimicrobial effects: A case study with ceftaroline and lefamulin

ObjectivePredictions of antimicrobial effects typically rely on plasma-based pharmacokinetic-pharmacodynamic (PK-PD) targets, ignoring target-site concentrations and potential differences in tissue penetration between antibiotics. In this study, we applied PK-PD modelling to compare target site-specific effects of antibiotics by integrating clinical microdialysis data, in vitro time-kill curves, and antimicrobial susceptibility distributions. As a case study, we compared the effect of lefamulin and ceftaroline against methicillin-resistant Staphylococcus aureus (MRSA) at soft-tissue concentrations. MethodsA population PK model describing lefamulin concentrations in plasma, subcutaneous adipose and muscle tissue was developed. For ceftaroline, a similar previously reported PK model was adopted. In vitro time-kill experiments were performed with six MRSA isolates and a PD model was developed to describe bacterial growth and antimicrobial effects. The clinical PK and in vitro PD models were linked to compare antimicrobial effects of ceftaroline and lefamulin at the different target sites. ResultsConsidering minimum inhibitory concentration (MIC) distributions and standard dosages, ceftaroline showed superior anti-MRSA effects compared to lefamulin both at plasma and soft-tissue concentrations. Looking at the individual antibiotics, lefamulin effects were highest at soft-tissue concentrations, while ceftaroline effects were highest at plasma concentrations, emphasising the importance of considering target-site PK-PD in antibiotic treatment optimisation. ConclusionGiven standard dosing regimens, ceftaroline appeared more effective than lefamulin against MRSA at soft-tissue concentrations. The PK-PD model-based approach applied in this study could be used to compare or explore the potential of antibiotics for specific indications or in populations with unique target-site PK.

Bycatch and pollution are the main threats for Burmeister's porpoises inhabiting a high-industrialized bay in the Humboldt Current System

Pollution and bycatch are two of the main threats for cetaceans worldwide. These threats are exacerbated for nearshore species particularly for those in regions with intense industrial and fishing activities. Burmeister's porpoise is endemic to South America, has a Near Threatened conservation status because of long-term mortality in fisheries. Burmeister's porpoise occur in Mejillones Bay, northern Chile, a hot spot for heavy metals pollution from the mining industry and an intense industrial and artisanal purse-seine fishing area. From 2018 to 2021, we conducted systematic marine surveys to assess the abundance, distribution and habitat use of Burmeister's porpoises. We responded to stranding reports from 2018 to 2022, and necropsied nine individuals. From five of these, we analyzed the metal concentrations (As, Cd, Cr, Cu, Pb, Hg, Se and Zn) in muscle and skin tissues. Results showed an abundance of 76.17 individuals (CV = 25.9%) and an average density of 0.45 individuals/km2 (CV = 26%). Burmeister's porpoises were observed year round, 22.2% were mother-calf pairs present in austral summer at an average of 90.6 m depth in the southwestern bound of the bay. Two-thirds of stranded specimens died due to bycatch and one died due to bottlenose dolphin (Tursiops truncatus) attack. We report a dead Burmeister's porpoise positive for avian flu virus A (H5N1). Metals analyzed were found in muscle and skin tissues of stranded Burmeister's porpoises in the following order (Zn > Cu > Cr > As > Hg > Pb > Cd). Although we could not assess pollution as a cause of mortality, Cr, As and Pb concentrations exceeded the concentrations found in other porpoises species worldwide. We conclude that bycatch and pollution as the main threats for Burmeister's porpoise survival in northern Chile. Future studies should investigate the use of acoustic deterrent alarms to mitigate the bycatch in the bay and consider the Burmeister's porpoise as a sentinel species of pollution in northern Chilean coast.

Effects of temperature acclimation on the upper thermal tolerance of two Arctic fishes.

The thermally dynamic nearshore Beaufort Sea, Alaska, is experiencing climate change-driven temperature increases. Measuring thermal tolerance of broad whitefish (Coregonus nasus) and saffron cod (Eleginus gracilis), both important species in the Arctic ecosystem, will enhance understanding of species-specific thermal tolerances. The objectives of this study were to determine the extent that acclimating broad whitefish and saffron cod to 5°C and 15°C changed their critical thermal maximum (CTmax) and HSP70 protein and mRNA expression in brain, muscle and liver tissues. After acclimation to 5°C and 15°C, the species were exposed to a thermal ramping rate of 3.4°C · h-1 before quantifying the CTmax and HSP70 protein and transcript concentrations. Broad whitefish and saffron cod acclimated to 15°C had a significantly higher mean CTmax (27.3°C and 25.9°C, respectively) than 5°C-acclimated fish (23.7°C and 23.2°C, respectively), which is consistent with trends in CTmax between higher and lower acclimation temperatures. There were species-specific differences in thermal tolerance with 15°C-acclimated broad whitefish having higher CTmax and HSP70 protein concentrations in liver and muscle tissues than saffron cod at both acclimation temperatures. Tissue-specific differences were quantified, with brain and muscle tissues having the highest and lowest HSP70 protein concentrations, respectively, for both species and acclimation temperatures. The differences in broad whitefish CTmax between the two acclimation temperatures could be explained with brain and liver tissues from 15°C acclimation having higher HSP70a-201 and HSP70b-201 transcript concentrations than control fish that remained in lab-acclimation conditions of 8°C. The shift in CTmax and HSP70 protein and paralogous transcripts demonstrate the physiological plasticity that both species possess in responding to two different acclimation temperatures. This response is imperative to understand as aquatic temperatures continue to elevate.

Bioaccumulation of mercury in Lake Michigan painted turtles (Chrysemys picta).

Mercury (Hg) contamination of aquatic environments can lead to bioaccumulation in organisms, but most previous work has focused on fish and not on semi-aquatic reptiles such as turtles that traverse both terrestrial and aquatic habitats. Here, we analyzed total Hg (THg) concentrations in 30 painted turtles (Chrysemys picta) collected from Lake Michigan (USA) coastal wetlands in 2013 to determine if (1) turtles bioaccumulated THg from the environment, (2) concentrations differed between turtle liver and muscle tissue, and (3) tissue concentrations were related to environmental concentrations (e.g., sediment THg). All individual turtles had detectable THg concentrations in both liver and muscle tissue. On average, THg concentrations were over three times higher in liver tissue compared to muscle tissue. We found a positive linear relationship between muscle THg concentrations and turtle body mass, a proxy for age, suggesting bioaccumulation in this species. Neither liver nor muscle THg concentrations followed the sediment contaminant gradient in the wetlands. Despite this, location was a strong predictor of tissue concentration in a linear model suggesting that other site-specific characteristics may be important. Overall, our results demonstrate that painted turtles accumulate mercury in liver and muscle tissues at different rates, which may be constrained by local conditions. Further research is needed to better understand the relationship between environmental mercury concentrations and body burdens in animals like turtles that traverse habitats. In addition, long-lived turtles could be incorporated into pollution monitoring programs to provide a more holistic picture of food web contamination and ecosystem health.

Evaluation of Mercury Pollution and Risk Assessment of Human Health due to Consumption of Common Carp (Cyprinus Carpio) from the Caspian Sea

Background: In the present study, the main goal was to measure the concentration of mercury in the muscle tissue of common carp and evaluate the health risk to consumers using different indices, and evaluate the possible difference between the values of the studied element in the sampling stations. Methods: Samples of the studied species were collected from four different stations, Bandar torkaman, Faridunknar, Chalus, and Bandar Anzali, from the southern shores of the Caspian sea. Kruskal-wallis and Mann-whitney u tests were used to determine the difference in mercury concentration in fish muscle tissue at the stations.

Assessment of human health risks through the consumption of mercury contaminated fish from gold and platinum mining areas

ABSTRACTMining activities can pollute freshwater systems with toxic contaminants that can damage the environment and cause risks to human health. In South Africa, mercury is a contaminant of major concern due to it being released into the environment through artisanal gold mining and the coal combustion process at power stations. Mercury accumulates in the liver and more importantly the muscle tissue of fish. Mercury can then be transferred to humans through the consumption of contaminated fish and can affect the nervous system and cause permanent damage. Although South Africa is a major contributor to global mercury emissions, there are very few papers published on mercury concentrations and the risks to human health associated with consuming contaminated fish. This study aimed to determine the mercury concentrations in environmental matrices (water, sediment and two fish species (Cyprinus carpio and Clarias gariepinus)) from five sites and determine the risks to human health associated with the consumption of these fish. The mercury concentrations in muscle and liver tissues of C. carpio (1.2 and 0.8 mg/kg) and C. gariepinus (1.6 and 0.9 mg/kg) from Boskop Dam were the highest across all sites. Clarias gariepinus had higher mercury concentrations and a higher risk to human health compared to C. carpio across all sites. Both species from Boskop Dam and the Vaal River, while C. gariepinus from Olifantsnek and Modder Dam all had a hazard quotient of > 1 which shows these fish had a high possibility for adverse health effects to humans.

Topical Delivery Systems Effectively Transport Analgesics to Areas of Localized Pain via Direct Diffusion.

Topical delivery systems (TDSs) enable the direct transport of analgesics into areas of localized pain and thus minimize the side effects of administration routes that rely on systemic drug distribution. For musculoskeletal pain, clinicians frequently prescribe topical products containing lidocaine or diclofenac. This study assessed whether drug delivery from a TDS into muscle tissue occurs mainly via direct diffusion or systemic transport. An investigational TDS containing 108 mg lidocaine (SP-103, 5.4% lidocaine), a commercially available TDS containing 36 mg lidocaine (ZTlido®, 1.8% lidocaine), and a topical pain relief gel (Pennsaid®, 2% diclofenac) were tested. Using open flow microperfusion (OFM), interstitial fluid from the dermis, subcutaneous adipose tissue (SAT), and muscle was continuously sampled to assess drug penetration in all tissue layers. Ex vivo and in vivo experiments showed a higher diffusive transport of lidocaine compared to diclofenac. The data showed a clear contribution of diffusive transport to lidocaine concentration, with SP-103 5.4% resulting in a significantly higher lidocaine concentration in muscle tissue than commercially available ZTlido® (p = 0.008). These results indicate that SP-103 5.4% is highly effective in delivering lidocaine into muscle tissue in areas of localized pain for the treatment of musculoskeletal pain disorders (e.g., lower back pain).

Mercury Contamination as an Indicator of Fish Species' Trophic Position in the Middle Araguaia River, Brazil.

This study evaluates the use of mercury (Hg) concentrations in fish muscle tissue to determine a species' trophic position (TP) in its environment. A campaign conducted in 2019 along 375 km in the middle Araguaia River basin, Brazil, resulted in 239 organisms from 20 species collected. The highest total mercury (THg) concentrations were found in Pellonacastelnaeana (6.93 µg·g-1, wet weight) and in Triportheus elongatus (3.18 µg·g-1, wet weight), whose TPs were different according to the FishBase database. However, they occupied the same trophic level in this study. The intra-specific comparison showed a difference in Hg concentrations between individuals captured in distinct sites. The study of the biota-sediment accumulation factor (BSAF) showed that spatiality interferes with a species' TP. Statistical analyses revealed that when we used a predicted species' TP based on each individual's size, it explained 72% of the variability in THg concentration across all fish species. Multiple regression analysis confirmed that standard length and FishBase values are positively associated with THg (R2 = 0.943). These results point to Hg as a viable indicator of a fish species' TP since it reflects regional, biological, and environmental factors, as demonstrated here for the middle Araguaia River.