Immune-pineal-ocular axis in amphibians: unveiling a novel connection?

Melatonin is a hormone known as an endogenous temporal marker signaling the dark phase of the day. Although the eyes seem to be the main site of melatonin production in amphibians, little information is available about the natural variation in the ocular melatonin levels and its modulation following immune stimulation. We investigated the daily variation of plasma and ocular melatonin levels in bullfrogs (Lithobates catesbeianus) and their modulation following an immune stimulation with lipopolysaccharide (LPS) in yellow cururu toads (Rhinella icterica). For the daily variation, bullfrogs were bled and then euthanized for eye collection every 3h over 24h to determine plasma and ocular melatonin levels. We found a positive correlation between ocular and plasma melatonin levels, with maximum values at night (22h) for both plasma and the eyes. For immune stimulation, yellow cururu toads received an intraperitoneal injection of LPS or saline solution during the day (10h) or at night (22h). Two hours after injection, toads were bled and euthanized for eye collection to obtain plasma and ocular melatonin levels. In addition, the liver and bone marrow were collected to investigate local melatonin modulation. Our results demonstrate that retina light-controlled rhythmic melatonin production is suppressed while liver and bone marrow melatonin levels increase during the inflammatory assemblage in anurans. Interestingly, the LPS injection decreased only ocular melatonin levels, reinforcing the central role of the eyes (i.e., retina) as an essential organ of melatonin production, and a similar role to the pineal gland during the inflammatory response in amphibians. Together, these results point to a possible immune-pineal-ocular axis in amphibians, yet to be fully described in this group.

The Cloning and Characterization of a Three-Finger Toxin Homolog (NXH8) from the Coralsnake Micrurus corallinus That Interacts with Skeletal Muscle Nicotinic Acetylcholine Receptors.

Coralsnakes (Micrurus spp.) are the only elapids found throughout the Americas. They are recognized for their highly neurotoxic venom, which is comprised of a wide variety of toxins, including the stable, low-mass toxins known as three-finger toxins (3FTx). Due to difficulties in venom extraction and availability, research on coralsnake venoms is still very limited when compared to that of other Elapidae snakes like cobras, kraits, and mambas. In this study, two previously described 3FTx from the venom of M. corallinus, NXH1 (3SOC1_MICCO), and NXH8 (3NO48_MICCO) were characterized. Using in silico, in vitro, and ex vivo experiments, the biological activities of these toxins were predicted and evaluated. The results showed that only NXH8 was capable of binding to skeletal muscle cells and modulating the activity of nAChRs in nerve-diaphragm preparations. These effects were antagonized by anti-rNXH8 or antielapidic sera. Sequence analysis revealed that the NXH1 toxin possesses eight cysteine residues and four disulfide bonds, while the NXH8 toxin has a primary structure similar to that of non-conventional 3FTx, with an additional disulfide bond on the first loop. These findings add more information related to the structural diversity present within the 3FTx class, while expanding our understanding of the mechanisms of the toxicity of this coralsnake venom and opening new perspectives for developing more effective therapeutic interventions.

Prevalence and risk factors for Q fever, spotted fever group rickettsioses, and typhus group rickettsioses in a pastoralist community of northern Tanzania, 2016-2017.

BACKGROUND: In northern Tanzania, Q fever, spotted fever group (SFG) rickettsioses, and typhus group (TG) rickettsioses are common causes of febrile illness. We sought to describe the prevalence and risk factors for these zoonoses in a pastoralist community. METHODS: Febrile patients ≥2 years old presenting to Endulen Hospital in the Ngorongoro Conservation Area were enrolled from August 2016 through October 2017. Acute and convalescent blood samples were collected, and a questionnaire was administered. Sera were tested by immunofluorescent antibody (IFA) IgG assays using Coxiella burnetii (Phase II), Rickettsia africae, and Rickettsia typhi antigens. Serologic evidence of exposure was defined by an IFA titre ≥1:64; probable cases by an acute IFA titre ≥1:128; and confirmed cases by a ≥4-fold rise in titre between samples. Risk factors for exposure and acute case status were evaluated. RESULTS: Of 228 participants, 99 (43.4%) were male and the median (interquartile range) age was 27 (16-41) years. Among these, 117 (51.3%) had C. burnetii exposure, 74 (32.5%) had probable Q fever, 176 (77.2%) had SFG Rickettsia exposure, 134 (58.8%) had probable SFG rickettsioses, 11 (4.8%) had TG Rickettsia exposure, and 4 (1.8%) had probable TG rickettsioses. Of 146 participants with paired sera, 1 (0.5%) had confirmed Q fever, 8 (5.5%) had confirmed SFG rickettsioses, and none had confirmed TG rickettsioses. Livestock slaughter was associated with acute Q fever (adjusted odds ratio [OR] 2.54, 95% confidence interval [CI] 1.38-4.76) and sheep slaughter with SFG rickettsioses case (OR 4.63, 95% CI 1.08-23.50). DISCUSSION: Acute Q fever and SFG rickettsioses were detected in participants with febrile illness. Exposures to C. burnetii and to SFG Rickettsia were highly prevalent, and interactions with livestock were associated with increased odds of illness with both pathogens. Further characterisation of the burden and risks for these diseases is warranted.

IL-10-induced STAT3/NF-κB crosstalk modulates pineal and extra-pineal melatonin synthesis.

Immune-pineal axis activation is part of the assembly of immune responses. Proinflammatory cytokines inhibit the pineal synthesis of melatonin while inducing it in macrophages by mechanisms dependent on nuclear factor-κB (NF-κB) activation. Cytokines activating the Janus kinase/signal transducer and activator of transcription (STAT) pathways, such as interferon-gamma (IFN-γ) and interleukin-10 (IL-10), modulate melatonin synthesis in the pineal, bone marrow (BM), and spleen. The stimulatory effect of IFN-γ upon the pineal gland depends on STAT1/NF-κB interaction, but the mechanisms controlling IL-10 effects on melatonin synthesis remain unclear. Here, we evaluated the role of STAT3 and NF-κB activation by IL-10 upon the melatonin synthesis of rats' pineal gland, BM, spleen, and peritoneal cells. The results show that IL-10-induced interaction of (p)STAT3 with specific NF-κB dimmers leads to different cell effects. IL-10 increases the pineal's acetylserotonin O-methyltransferase (ASMT), N-acetylserotonin, and melatonin content via nuclear translocation of NF-κB/STAT3. In BM, the nuclear translocation of STAT3/p65-NF-κB complexes increases ASMT expression and melatonin content. Increased pSTAT3/p65-NF-κB nuclear translocation in the spleen enhances phosphorylated serotonin N-acetyltransferase ((p)SNAT) expression and melatonin content. Conversely, in peritoneal cells, IL-10 leads to NF-κB p50/p50 inhibitory dimmer nuclear translocation, decreasing (p)SNAT expression and melatonin content. In conclusion, IL-10's effects on melatonin production depend on the NF-κB subunits interacting with (p)STAT3. Thus, variations of IL-10 levels and downstream pathways during immune responses might be critical regulatory factors adjusting pineal and extra-pineal synthesis of melatonin.

Diaphragmatic and excursion thickness in newborns using diaphragmatic kinesiology ultrasound: an observational study / Espessura e excursão diafragmática em recém-nascidos usando ultrassonografia cinesiológica do diafragma: um estudo observacional

Abstract Introduction The study of the diaphragm muscle has aroused the interest of physiotherapists who work with kinesiological ultrasonography, but still little explored; however, its findings can contribute to the clinical practice of hospitalized patients in neonatal intensive care units. Objective To measure the excursion and thickening of the diaphragm and describe measurements among neonates, preterm, and full-term. Methods Diaphragmatic kinesiological ultrasonography was performed on hospitalized newborns, in Neonatal Unit Care Unit, placed in supine position in their own bed, on the sixth day of life. Three repeated measurements of the same respiratory cycle were made, both for excursion and for diaphragmatic thickening. Results 37 newborns participated in the study and 25 were premature. The mean weight at the time of collection was 2,307.0 ± 672.76 grams and the gestational age was 35.7 ± 3.3 weeks. Diaphragmatic excursion increased with increasing gestational age (p = 0.01, df = 0.21) in term infants (p = 0.17, df = 0.35). Conclusion There was a positive correlation between diaphragmatic excursion and gestational age. There was no statistically significant difference in the measurements of excursion and inspiratory diaphragm thickening between preterm and term newborns, although pointing to higher measurements in the latter group.

Resumo Introdução O estudo do músculo diafragma tem des-pertado o interesse dos fisioterapeutas que trabalham com ultrassonografia cinesiológica. Ainda pouco explo-rado, contudo, seus achados podem contribuir para a prática clínica dos pacientes internados em unidades de terapia intensiva neonatal (UTIN). Objetivo Mensurar a excursão e o espessamento diafragmático e descrever as medidas entre recém-nascidos prematuros e a termo. Métodos Realizou-se ultrassonografia cinesiológica diafragmática em recém-nascidos internados em UTIN, posicionados em supino em seu próprio leito, no sexto dia de vida. Foram realizadas três medidas repetidas do mesmo ciclo respiratório, tanto da excursão quanto do espessamento diafragmático. Resultados Participaram do estudo 37 recém-nascidos, dos quais 25 eram pre-maturos. O peso no momento da coleta foi de 2.307,0 ± 672,76 gramas e a idade gestacional foi de 35,7 ± 3,3 semanas. A excursão diafragmática aumentou de acordo com o aumento da idade gestacional (p = 0,01; df = 0,21). A espessura variou entre 0,10 e 0,16 cm durante a inspiração nos prematuros e entre 0,11 e 0,19 cm nos nascidos a termo (p = 0,17; df = 0,35). Conclusão Houve correlação positiva entre a excursão diafragmá-tica e a idade gestacional. Não observou-se diferença estatisticamente significativa das medidas de excursão e de espessamento diafragmático inspiratório entre recém-nascidos prematuros e recém-nascidos a termo, embora apontando para maiores medidas neste último grupo.

Chronobiological parameters as predictors of early treatment response in major depression.

BACKGROUND: Alterations in circadian system organization have been related to major depressive disorder manifestations. This study aimed to evaluate chronobiological parameters, such as sleep, levels of 6-sulfatoxymelatonin, and others derived from actimetry as potential predictors of adequate treatment response in MDD. METHODS: 98 adult women with confirmed diagnosis of MDD were included. Participants completed standard questionnaires (Hamilton Depression Rating Scale - HAM-D; Munich Chronotype Questionnaire - MCTQ) at baseline and after 4 weeks of treatment. Urinary samples for assessing 6-sulfatoxymelatonin were collected on the day before and immediately after pharmacological treatment administration, and 28 continuous days of actigraphy data were collected during the protocol. Participants were classified into Responder (R) or Non-responder (NR) to antidepressant treatment in 4 weeks (early responder), which was characterized by a ≥50 % decrease in the HAM-D score. RESULTS: The following biological rhythms variables significantly predicted a better treatment response in a model controlling for age, sex, and previous treatments: higher levels of activity (M10 - average activity in the 10 most active hours within the 24 h-day) and an earlier center of the 10 most active hours (M10c), as well as lower intradaily variability (IV) of light exposure. Sleep parameters and 6-sulfatoxymelatonin levels did not associate with treatment response prediction. LIMITATION: Actimetry data were not assessed before changing in the treatment plan. CONCLUSION: Different patterns in activity and light exposure might be linked to early antidepressant response.

Rat resistance to rheumatoid arthritis induction as a function of the early-phase adrenal-pineal crosstalk.

Chronic inflammatory diseases are triggered by causal stimuli that might occur long before the appearance of the symptoms. Increasing evidence suggests that these stimuli are necessary but not always sufficient to induce the diseases. The murine model of type II collagen emulsified in Freund's incomplete adjuvant (collagen-induced arthritis) to induce rheumatoid arthritis (RA) follows this pattern as some animals do not develop the chronically inflamed phenotype. Considering that in the immune-pineal axis (IPA) theory adrenal-pineal cross-talk adjusts early phases of inflammatory processes, we investigated whether differences in IPA activation could explain why some animals are resistant (RES) while others develop RA. We observed a similar increase in 6-sulfatoxymelatonin (aMT6s) excretion from day 3 to 13 in both RES and RA animals, followed by a significant decrease in RA animals. This pattern of aMT6s excretion positively correlated with plasma corticosterone (CORT) in RES animals. Additionally, RA animals presented a lower aMT6s/CORT ratio than saline-injected or RES animals. Plasmatic levels of tumour necrosis factor were similar in both groups, but interleukin (IL)-1ß and monocyte chemotactic protein 1 (MCP-1) levels were lower in RES compared to RA animals. IL-2 and IL-4 were decreased in RES animals compared to saline-injected animals. The aMT6s/CORT ratio inversely correlated with the paw thickness and the inflammatory score (levels of IL-1ß, MCP-1, IL-2 and IL-4 combined). Thus, adrenocortical-pineal positive interaction is an early defence mechanism for avoiding inflammatory chronification. KEY POINTS: Immune-pineal axis imbalance is observed in early-phase rheumatoid arthritis development. Only resistant animals present a positive association between adrenal and pineal hormones. The 6-sulfatoxymelatonin/corticosterone ratio is decreased in animals that develop rheumatoid arthritis. The inflammatory score combining the levels of nocturnal interleukin (IL)-1ß, monocyte chemotactic protein 1, IL-2 and IL-4 presents a very strong positive correlation with the size of inflammatory lesion. The 6-sulfatoxymelatonin/corticosterone ratio presents a strong negative correlation with the inflammatory score and paw oedema size.

Community practices of face mask use and associated knowledge and attitude in a Malaysian town during the COVID-19 pandemic.

Objectives: Among the vital measures to effectively curb the incidence of COVID-19 is the use of face masks. Little is known about what people understand and how they perceive and use face masks. This study aimed to determine the community's knowledge, attitude, and practice on the correct use of face masks. Design: A cross-sectional study. Setting: The study was carried out in Seremban 2, Malaysia using a self-administered questionnaire adapted from validated questionnaires of two previous studies. Participants: Through opportunistic sampling, three hundred and ninety-two literate adults (above 18) residing in Seremban 2, Malaysia, participated in this study. Main outcome measure: Knowledge, attitude, and practice scores were assessed among the participants. Results: Three hundred seventy (94.4%) respondents demonstrated satisfactory knowledge. A satisfactory attitude score was achieved by 349 (89%) respondents, while 281 (71.7%) achieved a satisfactory practice score. Better knowledge was significantly associated with college or university education (p=0.028). Female gender (p=0.011) and college or university education (p=0.043) were significantly associated with better practice (p<0.05). Significant but weak to fair correlations between knowledge, attitude and practice were observed. Conclusion: Overall, there was satisfactory knowledge, attitude, and practice of face mask use among the Seremban 2 adult population in Malaysia. However, future public health education targeted toward the use of face masks requires more emphasis on proper usage and disposal to translate good knowledge into a good attitude and practice of face mask use to ensure the effectiveness in curbing the spread of infection. Funding: None declared.

Addressing vaccine hesitancy during the COVID-19 pandemic: Learning from the past and moving forward

Excerpt@#Anong hirap ang kailangan niyong maranasan para kayo ay magpabakuna na? How much suffering are you willing to risk experiencing to persuade you to go for COVID-19 vaccination? @*@#Working at a COVID-19 Referral Center, we probably saw a lot more critically ill COVID-19 patients than in other hospitals in the Philippines. During the height of the Delta surge in 2021, our intensive care units (ICUs) for adults and pediatric critical COVID-19 were always full with a long waiting line. The typical medical history of the patients would be a senior retiree, usually a Lolo (grandfather) or a Lola (grandmother), who needed urgent support to be hooked to a mechanical ventilator because they could not breathe on their own anymore. When asked about their COVID-19 vaccination status, Lolo and Lola were often not vaccinated. Other times, the patient may not yet be old enough to be considered a Lolo or Lola but may have illnesses like heart failure, diabetes, hypertension, or on dialysis. They too were often not vaccinated. And occasionally, we admitted small children who would seemingly be out of place in the sea of adult patients in the Emergency Room. One would think that because the very young have not yet been allowed to get vaccinated, the people around them would strive to be vaccinated to protect these little ones. On the contrary, though, we saw many young patients whose exposures to COVID-19 came from their unvaccinated parents. This heartbreaking situation continued despite the intensive COVID-19 vaccination program of our government. When one thinks about it, it is possible that some of the many deaths and sufferings of patients and the anguish of grieving families, as well as the lonely exits of beloved ones dying alone amidst CPR machines and teams, may have been avoided had unvaccinated patients opted to be vaccinated. Now over 2 ½ years into the pandemic with many cases said to be mild, we continue to have a continuous flow of admissions for COVID-19 which fall into the moderate, severe, and even critical COVID-19, and some of them are because they have remained unvaccinated. Where and how can we improve the situation?

When the choices we make will affect others

@#“Is it my problem if my father-in-law does not want to get vaccinated?” All of us must have encountered scenarios like the above. We have all met individuals who refused or hesitate to get vaccinated for COVID-19. They could be from our family members, our colleagues, our friends, our employees, our neighbors, our school, or communities, from anywhere! We do not need to look far. What will we do? Or how should we approach these situations? For more than a year now, we have been witnessing the unfolding of the roll out of the “biggest” vaccine drives in history. Furthermore, this COVID-19 pandemic challenged every individual to make a personal stand about accepting and even promoting vaccination. This issue of the Acta Medica Philippina includes two contributions that give us different perspectives on the phenomenon called “Vaccine Hesitancy.” Vaccine hesitancy is reluctance or refusal to get vaccinated even with the availability of vaccines. While vaccine hesitancy is observed across the world, our issue looks specifically at the factors which contribute to the unique experiences in the Southeast Asian region and even more specifically to our country. These discussions will lead to a better understanding of drivers, both barriers and enablers to vaccine acceptance and uptake. This timely sharing of information comes at that crucial period when the vaccine hesitancy rates are high in our country despite efforts of our government to persuade as many individuals as possible to come for their COVID-19 booster vaccines. The World Health Organization (WHO) released guidance for countries and governments on how they can improve the vaccine uptake of their constituents.1 In addition to addressing the need for up-to-date information campaigns, governments and other “actors” who play major roles in the implementation of the vaccination program, especially during the current pandemic, need to listen and attune themselves to the main drivers of vaccine acceptance versus hesitancy. These are: 1) providing an enabling environment, 2) social influences; and 3) motivation. The paper of Hartigan-Go and group shows vaccine hesitancy research and how this information may be used to strategize vaccine education and communication campaigns to increase vaccine uptake.2 The invited essay is a discussion on how the traumatic experience we all witnessed in recent national history with another novel vaccine is an important driver negatively affecting behavior toward vaccination campaigns; and how can we move forward from there.3 We hope these contributions will help us all appreciate and respect the complexity of behavior related to vaccination, persuade our countrymen towards action that will help us achieve our desired goals for more, and work towards attaining our goal of better health for all.

MEL-Index: Estimation of Tissue Melatonin Levels Using Gene Expression Data.

Melatonin synthesis by extrapineal sources adjusts physiological and pathophysiological processes in several types of cells and tissues. As measuring locally produced melatonin in fresh tissues might be a challenge due to limited material availability, we created a simple predictive model, the MEL-Index, which infers the content of tissue melatonin using gene expression data. The MEL-Index can be a powerful tool to study the role of melatonin in different contexts. Applying the MEL-Index method to RNA-seq datasets, we have shed light into the clinical relevance of melatonin as a modulator tumor progression and lung infection due to COVID-19. The MEL-Index combines the z-normalized expressions of ASMT (Acetylserotonin O-Methyltransferase), last enzyme of the biosynthetic pathway, and CYP1B1 (cytochrome P450 family enzyme), which encodes the enzyme that metabolizes melatonin in extrahepatic tissues. In this chapter, we describe the steps for calculating the MEL-Index.

Brain Damage-linked ATP Promotes P2X7 Receptors Mediated Pineal N-acetylserotonin Release.

The pineal gland is a key player in surveillance and defense responses. In healthy conditions, nocturnal circulating melatonin (MEL) impairs the rolling and adhesion of leukocytes to the endothelial layer. Fungi, bacteria, and pro-inflammatory cytokines block nocturnal pineal MEL synthesis, facilitating leukocyte migration to injured areas. ATP is a cotransmitter of the noradrenergic signal and potentiates noradrenaline (NAd)-induced MEL synthesis via P2Y1 receptor (P2Y1R) activation. Otherwise, ATP low-affinity P2X7 receptor (P2X7R) activation impairs N-acetylserotonin (NAS) into MEL conversion in NAd incubated pineals. Here we mimicked a focal increase of ATP by injecting low (0.3 and 1.0 µg) and high (3.0 µg) ATP in the right lateral ventricle of adult rats. Nocturnal pineal activity mimicked the in culture data. Low ATP doses increased MEL output, while high ATP dose and the P2X7R agonist BzATP (15.0-50.0 ng) increased NAS pineal and blood content. In the brain, the response was structure-dependent. There was an increase in cortical and no change in cerebellar MEL. These effects were mediated by changes in the expression of coding genes to synthetic and metabolizing melatonergic enzymes. Thus, the pineal gland plays a role as a first-line structure to respond to the death of cells inside the brain by turning NAS into the darkness hormone.

Hydrophobic π-π stacking interactions and hydrogen bonds drive self-aggregation of luteolin in water.

Luteolin is a flavonoid obtained from different plant species. It is known for its versatile biological activities. However, the beneficial effects of luteolin have been limited to small concentrations as a result of poor water solubility. This study aimed at investigating the hydrophobic interaction and hydration of luteolin towards the improvement of its solubility when used as a drug. We report the aggregation properties of luteolin in water by varying the number of monomers using atomistic molecular dynamics simulation. Results show that the equilibrium structure of luteolin occurs in an aggregated state with different structural arrangements. As the monomers size increase, the antiparallel flipped conformation dominates over T-shaped antiparallel, T-shaped parallel, and antiparallel conformations. The formation of intramolecular hydrogen bonding of 0.19 nm between the keto-enol groups results in hydrophobic characteristics. A larger cluster exhibits slow hydrogen bond dynamics for luteolin-luteolin than luteolin-water interaction. Water structure at large cluster size exhibited slow dynamics and low self-diffusion of luteolin. The existence of hydrophobic π-π and hydrogen bonds between luteolin molecules drives strong self-aggregation resulting in poor water solubility. Breakage of these established interactions would result in increased solubility of luteolin in water.

Immune and endocrine responses of Cururu toads (Rhinella icterica) in their natural habitat after LPS stimulation.

Glucocorticoids and melatonin display immunomodulatory functions, with both immune-stimulatory and suppressor effects, depending on the context. While their immune properties are well-explored in mammals, there are still few studies on this immune-endocrine interaction in an inflammatory context in amphibians, all of them under captivity conditions, which can constitute a stressor for these animals. Evaluating how amphibians react to an immune challenge in the field would reveal relevant information regarding how immune-physiological parameters are modulated in natural conditions. This study aimed to investigate the effects of lipopolysaccharide (LPS) injection in male toads (Rhinella icterica) recently captured in their natural habitat in the Atlantic Forest at two different times of the day. We evaluated: splenic cytokines mRNA (interleukin [IL]-1ß, IL-6, IL-10, interferon-γ) and complement system protein (C1s), plasma bacterial killing ability (BKA), plasma corticosterone (CORT), melatonin (MEL), and testosterone (T) levels, and neutrophil to lymphocyte ratio (NLR), two hours post-injections. LPS-injection increased NLR, the gene expression of IL-1ß, and less evidently CORT levels independently of the time of the day. These results evidence LPS-induced inflammation, similarly observed in toads in captivity. Saline and LPS-injected toads showed a positive correlation between IL-1ß and IL-6, both cytokines with pro-inflammatory effects. Also, CORT was negatively associated with T, suggesting inhibition of the hypothalamus-pituitary-gonadal axis in the LPS-stimulated group. Our results are associated with the first stage of the inflammatory assemblage. Studies evaluating further steps of this process might lead to a better understanding of the immune-endocrine relations in amphibians.

Daily and LPS-induced variation of endocrine mediators in cururu toads (Rhinella icterica).

Increased plasma glucocorticoids (corticosterone - CORT, in amphibians) and melatonin (MEL) are associated with the daily activity phase and with environmental darkness, respectively. Besides, CORT and MEL also play pivotal immunomodulatory roles in several vertebrates. Herein we described the daily profile of plasma MEL and CORT for Rhinella icterica toads in captivity. Thereafter, we investigated the effects of lipopolysaccharide (LPS)-induced systemic inflammation on the production of CORT and MEL in the R. icterica. Captive toads showed CORT and MEL diurnal variation typical of nocturnal species, with increased values for CORT at ZT12 (18 h) and MEL peak at ZT18 (24 h). LPS-induced hormonal changes included increased plasma CORT and decreased ocular and plasma MEL when compared to those from toads treated with saline 2 h post-injection. Our results demonstrated the presence of a diurnal CORT and MEL variation in toads. We also showed the crosstalk between CORT and MEL during the toad's systemic inflammation in response to an immune challenge with LPS. Additionally, our results demonstrated that anuran eyes' MEL production might be regulated during the inflammatory processes.

Possible Role of Pineal and Extra-Pineal Melatonin in Surveillance, Immunity, and First-Line Defense.

Melatonin is a highly conserved molecule found in prokaryotes and eukaryotes that acts as the darkness hormone, translating environmental lighting to the whole body, and as a moderator of innate and acquired defense, migration, and cell proliferation processes. This review evaluates the importance of pineal activity in monitoring PAMPs and DAMPs and in mounting an inflammatory response or innate immune response. Activation of the immune-pineal axis, which coordinates the pro-and anti-inflammatory phases of an innate immune response, is described. PAMPs and DAMPs promote the immediate suppression of melatonin production by the pineal gland, which allows leukocyte migration. Monocyte-derived macrophages, important phagocytes of microbes, and cellular debris produce melatonin locally and thereby initiate the anti-inflammatory phase of the acute inflammatory response. The role of locally produced melatonin in organs that directly contact the external environment, such as the skin and the gastrointestinal and respiratory tracts, is also discussed. In this context, as resident macrophages are self-renewing cells, we explore evidence indicating that, besides avoiding overreaction of the immune system, extra-pineal melatonin has a fundamental role in the homeostasis of organs and tissues.

Melatonin and Depression: A Translational Perspective From Animal Models to Clinical Studies.

Daily rhythm of melatonin synchronizes the body to the light/dark environmental cycle. Several hypotheses have been raised to understand the intersections between melatonin and depression, in which changes in rest-activity and sleep patterns are prominent. This review describes key experimental and clinical evidence that link melatonin with the etiopathology and symptomatology of depressive states, its role in the follow up of therapeutic response to antidepressants, as well as the clinical evidence of melatonin as MDD treatment. Melatonin, as an internal temporal cue contributing to circadian organization and best studied in the context of circadian misalignment, is also implicated in neuroplasticity. The monoaminergic systems that underly MDD and melatonin production overlap. In addition, the urinary metabolite 6-sulfatoxymelatonin (aMT6) has been proposed as biomarker for antidepressant responders, by revealing whether the blockage of noradrenaline uptake has taken place within 24 h from the first antidepressant dose. Even though animal models show benefits from melatonin supplementation on depressive-like behavior, clinical evidence is inconsistent vis-à-vis prophylactic or therapeutic benefits of melatonin or melatonin agonists in depression. We argue that the study of melatonin in MDD or other psychiatric disorders must take into account the specificities of melatonin as an integrating molecule, inextricably linked to entrainment, metabolism, immunity, neurotransmission, and cell homeostasis.

Disrupted nocturnal melatonin in autism: Association with tumor necrosis factor and sleep disturbances.

Sleep disturbances, abnormal melatonin secretion, and increased inflammation are aspects of autism spectrum disorder (ASD) pathophysiology. The present study evaluated the daily urinary 6-sulfatoxymelatonin (aMT6s) excretion profile and the salivary levels of tumor necrosis factor (TNF) and interleukin-6 (IL-6) in 20 controls and 20 ASD participants, as well as correlating these measures with sleep disturbances. Although 60% of ASD participants showed a significant night-time rise in aMT6s excretion, this rise was significantly attenuated, compared to controls (P < .05). The remaining 40% of ASD individuals showed no significant increase in nocturnal aMT6s. ASD individuals showed higher nocturnal levels of saliva TNF, but not IL-6. Dysfunction in the initiation and maintenance of sleep, as indicated by the Sleep Disturbance Scale for Children, correlated with night-time aMT6s excretion (r = -.28, P < .05). Dysfunction in sleep breathing was inversely correlated with aMT6s (r = -.31, P < .05) and positively associated with TNF level (r = .42, P < .01). Overall such data indicate immune-pineal axis activation, with elevated TNF but not IL-6 levels associated with disrupted pineal melatonin release and sleep dysfunction in ASD. It is proposed that circadian dysregulation in ASD is intimately linked to heightened immune-inflammatory activity. Such two-way interactions of the immune-pineal axis may underpin many aspects of ASD pathophysiology, including sleep disturbances, as well as cognitive and behavioral alterations.

Early experience with COVID-19 patients in a private tertiary hospital in the Philippines: Implications on surge capacity, healthcare systems response, and clinical care.

BACKGROUND: Our healthcare institution was one of the first to see SARS CoV-2 cases in the country. We describe the early COVID-19 experience of a private hospital in the Philippines and discuss the healthcare system response in the setting of surge capacity. METHODS: We reviewed the medical records of adult COVID-19 hospitalized patients admitted in March 2020. We reported their demographic and clinical characteristics using descriptive statistics. RESULTS: Of 40 patients admitted, 23 (57.5%) were male and 19 (47.5%) were aged <60 years. Most (n = 27, 67.5%) had moderate-risk, 9 (22.5%) had high-risk, and 4 (10%) had low-risk COVID-19. SARS-CoV-2 testing took 5.5 (range 1-10) days. Overall mortality rate was 6/40 (15.0%). Clinical cure was documented in all low-risk patients, 25 (92.6%) moderate-risk patients, and only 1 (11.1%) high-risk patient. In response to the surge, the hospital rapidly introduced one-way traffic systems, dedicated screening, triage and Emergency Department areas for COVID-19, a clinical pathway, engineering controls, patient cohorting, and strict infection prevention and control measures. CONCLUSION: Majority of patients recovered from COVID-19. Older age and high-risk pneumonia were associated with poor outcomes. Adaptations to hospital structure and staff were quickly made in response to surge capacity, although our response was hampered by prolonged time to COVID-19 confirmation. Our study underscores the urgent need for rapid adaptive response by the healthcare system to address the surge of cases.

Hormonal daily variation co-varies with immunity in captive male bullfrogs (Lithobates catesbeianus).

Almost all physiological processes within the organism, including immune parameters and hormones, follow a circadian rhythm. These daily fluctuations are often observed in free-living organisms; however, little is known regarding hormonal and immune daily variations in anurans, particularly under laboratory conditions. This study aimed to investigate the hormonal and immune daily variation in captive-bred Bullfrogs (Lithobates catesbeianus) under constant conditions (21 °C and 12:12 LD cycle). Our results showed a daily variation for plasma corticosterone (CORT), testosterone (T), and melatonin (MEL), as well as for blood leukocyte profile, phagocytic activity, and plasma bacterial killing ability (BKA). Hormonal profile and immune activity were higher at the dark when compared with the light phase; however, monocytes and lymphocytes followed the opposite pattern. Moreover, CORT was positively correlated with phagocytosis percentage of blood cells, BKA, and monocytes, while MEL and T showed a positive correlation with PP. Our results demonstrate the daily covariation of different immune variables and immunomodulatory hormones. These 24 h-day variations and covariation certainly have broad implications and need to be considered for better understanding anuran physiology both in the context of laboratory and field studies.