Effects of the PREMEN-CALM® in the Management of the Premenstrual Syndrome: A Randomized, Double-Blind, Placebo-Controlled Pilot Study.

Premenstrual syndrome is a common disorder in women of reproductive age characterized by a variety of cyclical symptoms with a great impact on their lifestyle. Available pharmacological options include both antidepressants and oral contraceptives, both of which have side effects, are expensive and not always effective. Vitamins, minerals and plant extracts have been proven to alleviate the symptomatology of the premenstrual syndrome. For this reason, the purpose of this study was to test the effectiveness of a commercial phytotherapeutic dietary supplement (PREMEN-CALM®: γ-aminobutyric acid, Rhodiola rosea L., Vitex agnus-castus, vitamin B6 and melatonin) as an alternative treatment for this condition. A randomized, double-blind, and placebo-controlled pilot study was performed. Participants (n = 42) were assessed before and after 3 months of taking the supplement (n = 21) or the placebo (n = 21). Outcome measures include antioxidant and inflammatory biomarkers, body composition, subjective sleep quality, mood state profile, quality of life, and certain characteristics of the menstrual cycle. The within-group analysis revealed a significant improvement in the total antioxidant status (1.49 ± 0.34 vs reference value 1, p = 0.002), mood state profile (p = 0.02), and affective symptoms (p = 0.01) in the women receiving the commercial phytotherapeutic dietary supplement PREMEN-CALM®. On the contrary, the between-group analysis showed no statistical differences, suggesting a plausible placebo effect. The phytotherapeutic supplement PREMEN-CALM® might be effective in treating or alleviating the symptoms of the premenstrual syndrome without adverse events. Integrative medicine approaches in the clinical practice may help improve the health of women suffering from this and other gynecological conditions.

Long-term care facilities' response to the COVID-19 pandemic: An international, cross-sectional survey.

AIMS: To (i) assess the adherence of long-term care (LTC) facilities to the COVID-19 prevention and control recommendations, (ii) identify predictors of this adherence and (iii) examine the association between the adherence level and the impact of the pandemic on selected unfavourable conditions. DESIGN: Cross-sectional survey. METHODS: Managers (n = 212) and staff (n = 2143) of LTC facilities (n = 223) in 13 countries/regions (Brazil, Egypt, England, Hong Kong, Indonesia, Japan, Norway, Portugal, Saudi Arabia, South Korea, Spain, Thailand and Turkey) evaluated the adherence of LTC facilities to COVID-19 prevention and control recommendations and the impact of the pandemic on unfavourable conditions related to staff, residents and residents' families. The characteristics of participants and LTC facilities were also gathered. Data were collected from April to October 2021. The study was reported following the STROBE guidelines. RESULTS: The adherence was significantly higher among facilities with more pre-pandemic in-service education on infection control and easier access to information early in the pandemic. Residents' feelings of loneliness and feeling down were the most affected conditions by the pandemic. More psychological support to residents was associated with fewer residents' aggressive behaviours, and more psychological support to staff was associated with less work-life imbalance. CONCLUSIONS: Pre-pandemic preparedness significantly shaped LTC facilities' response to the pandemic. Adequate psychological support to residents and staff might help mitigate the negative impacts of infection outbreaks. IMPACT: This is the first study to comprehensively examine the adherence of LTC facilities to COVID-19 prevention and control recommendations. The results demonstrated that the adherence level was significantly related to pre-pandemic preparedness and that adequate psychological support to staff and residents was significantly associated with less negative impacts of the pandemic on LTC facilities' staff and residents. The results would help LTC facilities prepare for and respond to future infection outbreaks. PATIENT OR PUBLIC CONTRIBUTION: No Patient or Public Contribution.

Effects of Lycopene-enriched, Organic, Extra Virgin Olive Oil on Benign Prostatic Hyperplasia: A Pilot Study.

Context: Epidemiological evidence has shown that lycopene consumption may be effective in both the prevention and treatment of various diseases, particularly prostate cancer. However, the influence of this dietary carotenoid on some of the most basic aspects of human health remains unknown. Objectives: The aim of the study was to determine the effects of consumption of a lycopene-enriched commercial product of organic, extra virgin olive oil (EVOO) on prostate health, sleep quality, antioxidant status, and anxiety. Design: The research team designed a pilot study with two intervention groups. Setting: The study took place in the city of Badajoz (Extremadura, Spain). Participants: Participants were 20 men aged ≥50, some of whom were healthy and some of whom had received a diagnosis of benign prostatic hyperplasia. Intervention: Participants were divided into a healthy-men (HM) group (n = 10) and a benign prostatic hyperplasia (BPH) group (n = 10). Both groups consumed 20 ml of lycopene (0.4 mg/ml) daily in a lycopene-enriched commercial product of organic extra virgin olive oil, at breakfast and/or lunch, for 30 days. Outcome Measures: Sleep quality, prostate markers-prostatic specific antigen and protein C reactive-and symptomatology, urine total antioxidant status, and emotional health were assessed at baseline and postintervention. Results: The level of prostatic specific antigen and symptomatology remarkably improved in men with benign prostatic hyperplasia, although the changes wasn't statistically significant, and the total antioxidant status was significantly increased in healthy men (P < .05). Sleep quality in terms of nocturnal activity was significantly improved in both groups (P < .05). No adverse events were reported. Conclusion: The consumption of a lycopene-enriched, organic, EVOO positively influenced prostate health and other physiological variables. These findings may help to advance the development of new preventive and/or chemotherapeutic strategies based on lycopene.

SARS-CoV-2 Infection among School Population of One Developing Country. Do School Closures Protect Students and Teachers against SARS-CoV-2 Infection?

Evidence about the effectiveness of school closures as a measure to control the spread of COVID-19 is controversial. We posit that schools are not an important source of transmission; thus, we analyzed two surveillance methods: a web-based questionnaire and a telephone survey that monitored the impact of the pandemic due to COVID-19 cases in Bogotá, Colombia. We estimated the cumulative incidences for Acute Respiratory Infection (ARI) and COVID-19 for each population group. Then, we assessed the differences using the cumulative incidence ratio (CIR) and 95% confidence intervals (CI95%). The ARI incidence among students was 20.1 times higher when estimated from the telephone survey than from the online questionnaire (CIR: 20.1; CI95% 17.11-23.53). Likewise, the ARI incidence among schoolteachers was 10 times higher in the telephone survey (CIR: 9.8; CI95% 8.3-11.5). the incidence of COVID-19 among schoolteachers was 4.3 times higher than among students in the online questionnarie (CIR: 4.3, CI95%: 3.8-5.0) and 2.1 times higher in the telephone survey (CIR = 2.1, CI95%: 1.8-2.6), and this behavior was also observed in the general population data. Both methods showed a capacity to detect COVID-19 transmission among students and schoolteachers, but the telephone survey estimates were probably closer to the real incidence rate.

Tryptophan-rich diet is negatively associated with depression and positively linked to social cognition.

The essential amino acid tryptophan (TRP) is discussed as a potential protective factor for physical and mental health. Besides positive effects via the microbiota of the gut on many physiological processes, TRP is the precursor of the neurotransmitter serotonin (5-HT), thereby playing a role for affective disorders. The present study investigated the effects of a TRP-rich diet on depressiveness and on one of its endophenotypes, impaired social cognition, in a population based sample. N = 482 subjects participated in an online study, assessing the ability to properly recognize emotional states from the eye region of faces (Reading the Mind in the Eye Test, RMET) and asking for subjective ratings of condemnability in a moral judgment task. Moreover, the habitual TRP intake was measured. It was hypothesized that a low-TRP diet is associated with higher depressiveness and worse performance in the social cognition tasks. The main hypotheses could be supported. However, contrary to the expectations, the effect of TRP on social cognition was not mediated by depressiveness. Results show that a tryptophan-rich diet is a potential protective factor against depression and is positively related to functioning in social cognition.

Melatonin Improves Mood Status and Quality of Life and Decreases Cortisol Levels in Fibromyalgia.

BACKGROUND: Mood disturbances are implicated in the pathogenesis of fibromyalgia. The aim of this study was to assess the effect of different doses of melatonin on quality of life, mood status, pain, anxiety, and urinary cortisol levels in patients with fibromyalgia. METHODS: After a 10-day baseline period for the collection of data about participants' initial status, participants took different doses of melatonin for 10 consecutive days each, with placebo given during the 10 days either before or between melatonin doses. Participants' moods, quality of life, and pain levels were assessed using the Fibromyalgia Impact Questionnaire (FIQ), a Numerical Pain Scale (NPS), the State-Trait Anxiety Test (STAI), a Visual Analog Scale (VAS), and the Short Form-36 Health Survey (SF-36). Urinary cortisol levels were measured using enzyme-linked immunoassay. RESULTS: Doses of 9, 12, and 15 mg of melatonin were associated with decreases in the total score of the FIQ, NPS scores, and urinary cortisol levels. The State-Anxiety subscale of the STAI improved after the 12 mg dose. The scores on the VAS improved after the 9 mg dose. The dimensions evaluated in the SF-36 questionnaire improved after the 9 mg dose. CONCLUSION: Melatonin improved mood, anxiety levels, and quality of life while decreasing cortisol levels in patients with fibromyalgia.

Perception of effective access to health services in Territorial Spaces for Training and Reincorporation, one year after the peace accords in Colombia: a cross-sectional study.

Backgrounds: The signing of the peace accords in Colombia created challenges that are inherent to post-conflict transitions. One of those is the process of reintegrating ex-combatants into society, in which ensuring their rights to health is a particularly significant challenge in rural areas affected by armed conflict. These areas, known as Territorial Spaces for Training and ReintegrationReincorporation (ETCR, in Spanish), are geographically dispersed throughout 24 municipalities and 13 departments in Colombia. This study aimed to describe how ex-combatants in ETCR regions perceived access to health services one year after the signing of the peace accords. Methods: A descriptive, cross-sectional study was performed between September and October 2018. It included 591 adults and their families, from 23 ETCRs. The study was designed, culturally validated, and piloted. Interviewers were trained and a structured survey was administered containing five dimensions that characterized the perception of effective access to health services. Results: The majority of interviewees were women, heads of household, young adults, ex-combatants, and residents in an ETCR. In total of 96.4% were enrolled in Colombia's subsidized health system, and 20.8% indicated that a member of their household required emergency health services. The regional health center provided the majority of the services. Most of those surveyed (96.0%) reported that they did not have to pay for the services, and that they received respectful (91.6%) and good quality (66.6%) care. There were few referrals to disease prevention and health promotion activities, and only 19.0% of households reported having been visited by extramural health care teams, whose activities were highly valued (80%). Lastly, there was little knowledge about community health activities. Conclusions: While residents of ETCR regions have a favorable perception of their access to health services, they need to be made aware of extramural and public health activities.

Changes in Mediterranean dietary pattern of university students: a comparative study between Spain and Algeria / Cambios en el patrón dietético mediterráneo de estudiantes universitarios: un estudio comparativo entre España y Argelia

AIM: Assess and compare the diet quality of university students living in two different Mediterranean countries (Algeria and Spain). METHODS: 303 university students from two different Mediterranean areas (Algeria and Spain) were enrolled in this cross-sectional study. The data collection of students' diet and other personal variables was based on a self-reported method; a nutritional evaluation was carried out using the DIAL(R) nutritional software. RESULTS: There were found significant differences in the diets, not only because of gender but also nationality, probably due to inherent cultural and socioeconomic characteristics of each country resulting in variants of Mediterranean diet. CONCLUSIONS: Nutrition education programs based on the promotion of Mediterranean lifestyle must be aimed at all ages, but especially in university stage

OBJETIVO: evaluar y comparar la calidad de la dieta de los estudiantes universitarios que viven en dos países mediterráneos diferentes (Argelia y España). MÉTODO: 303 estudiantes universitarios de dos áreas mediterráneas diferentes (Argelia y España) se inscribieron en este estudio transversal. La recopilación de datos de la dieta de los estudiantes y otras variables personales se recogío mediante en un cuestionario autoinformado; Se realizó una evaluación nutricional utilizando el software nutricional DIAL(R). RESULTADOS: Se encontraron diferencias significativas en las dietas, no solo debido al género sino también a la nacionalidad, probablemente debido a las distintas características culturales y socioeconómicas de cada país que se reflejan en algunas variantes de la dieta mediterránea. CONCLUSIÓN: los programas de educación nutricional basados en la promoción del estilo de vida mediterráneo deben estar dirigidos a todas las edades, pero especialmente en la etapa universitaria

Melatonin increases the effect of 5-fluorouracil-based chemotherapy in human colorectal adenocarcinoma cells in vitro.

Melatonin has antitumor activity via several mechanisms including its anti-proliferative and pro-apoptotic effects. Moreover, it has been proven that melatonin in combination with chemotherapeutic agents enhances chemotherapy-triggered apoptosis in several types of cancer. Therefore, this study was intended to evaluate whether melatonin is able to strengthen the anti-cancer potential of different chemotherapeutic drugs in human colorectal adenocarcinoma HT-29 cells. We found that treatment with 20 µM cisplatin (CIS) or 1 mM 5-fluorouracil (5-FU) for 72 h induced a decrease in HT-29 cell viability. Furthermore, 1 mM melatonin significantly (P < 0.05) increased the cytotoxic effects of 5-FU. Likewise, simultaneous stimulation with 1 mM melatonin and 1 mM 5-FU significantly (P < 0.05) enhanced the ratio of cells with an overproduction of intracellular reactive oxygen species and substantially augmented the population of apoptotic cells compared to the treatment with 5-FU alone. Nonetheless, melatonin only displayed moderate chemosensitizing effects in CIS-treated HT-29 cells, as suggested by a slight increment in the fraction of early apoptotic cells that was observed only after 48 h. Consistently, co-stimulation of HT-29 cells with 20 µM CIS or 1 mM 5-FU in the presence of 1 mM melatonin further increased caspase-3 activation. Apart from this, the cytostatic activity displayed by CIS due to S phase arrest was not affected by concomitant stimulation with melatonin. Overall, our results indicate that melatonin increases the sensitivity of HT-29 cells to 5-FU treatment and, consequently, the indolamine could be potentially applied to colorectal adenocarcinoma treatment as a potent chemosensitizing agent.

Melatonin diminishes oxidative damage in sperm cells, improving assisted reproductive techniques.

Sperm preparation procedures are a potential generator of oxidative stress-induced DNA damage, which leads to a dramatic drop in fertility. An increasing number of studies suggest that melatonin reduces the oxidative stress induced by manipulation. However, very little is known about the preservative role of melatonin in sperm preparation medium during assisted reproduction procedures. For this aim to be achieved, semen was divided into two fractions and preincubated with and without 1 mM melatonin. Afterwards, both fractions were divided into two subfractions to perform swim-up in the presence and absence of 1 mM melatonin. Labeling with anti-CD46 and antiactive caspase-3 allowed the monitoring of acrosome reaction and apoptosis by flow cytometry. Sperm DNA fragmentation and compaction were analyzed through propidium iodide staining. The normozoospermic and oligozoospermic samples that were preincubated with melatonin underwent a significant increase in the ratio of adequate spermatozoa and a reduction of caspase-3 activation. Additionally, preincubation with melatonin enhanced the migration of sperm cells with compacted DNA in oligozoospermic samples (P < 0.05) and prevented DNA fragmentation in normozoospermic samples (P < 0.05). In light of the current results, the cytoprotective capacity and innocuousness of melatonin make it a great candidate to be applied in assisted reproduction techniques in order to prevent triaogenic oxidative damage.

Effects of melatonin on the oxidative damage and pancreatic antioxidant defenses in cerulein-induced acute pancreatitis in rats.

BACKGROUND: Oxidative stress is recognized as a pivotal effector of several pathogenic processes, including acute pancreatitis. Reactive oxygen species not just cause damage on the main cellular components, but also influence the expression of antioxidant system genes. Antioxidant molecules, such as melatonin, could be good candidates for the treatment of this multidimensional disease. The present study was to evaluate the chemopreventive effect of melatonin in a rat model of cerulein-induced acute pancreatitis. METHODS: Four subcutaneous injections of cerulein (20 µg/kg body weight) were given to Wistar rats at two hours intervals; melatonin was injected intraperitoneally (25 mg/kg body weight) 30 minutes before each injection of cerulein. Lipid peroxidation, protein oxidation (carbonyl groups), total antioxidant status, and glutathione peroxidase activity were determined in pancreatic tissue using commercial kits. RESULTS: The chemopreventive administration of melatonin caused a reduction in lipid peroxidation and protein oxidation due to injections of cerulein. Additionally, melatonin treatment was also able to revert glutathione peroxidase activity and total antioxidant status near to control levels, suggesting that melatonin could prevent from oxidative phenomena in the pancreas, such as lipid peroxidation and protein oxidation, and could stimulate, directly or indirectly, the expression of antioxidant enzymes. CONCLUSION: Melatonin, a polyvalent antioxidant, protected the pancreatic damage via the decrease of oxidative stress and increase of the activities of antioxidant enzymes in cerulein-induced acute pancreatitis.

Body weight gain in rats by a high-fat diet produces chronodisruption in activity/inactivity circadian rhythm.

In the last few decades, obesity has become one of the most important public health problems. Adipose tissue is an active endocrine tissue which follows a rhythmic pattern in its functions and may produce alterations in certain circadian rhythms. Our aim was to evaluate whether the locomotor activity circadian rhythm could be modified by a hypercaloric diet in rodents. Two groups were considered in the experiment: 16 rats were used as a control group and were fed standard chow; the other group comprised 16 rats fed a high-fat diet (35.8% fat, 35% glucides). The trial lasted 16 weeks. Body weight was measured every week, and a blood sample was extracted every two weeks to quantify triglyceride levels. The activity/inactivity circadian rhythm was logged through actimetry throughout the trial, and analysed using the DAS 24© software package. At the end of the experiment, the high-fat fed rats had obese-like body weights and high plasma triglyceride levels, and, compared with the control group, increased diurnal activity, decreased nocturnal activity, reductions in amplitude, midline estimating statistic of rhythm, acrophase and interdaily stability, and increases in intradaily variability of their activity rhythms. The results thus show how obesity can lead to symptoms of chronodisruption in the body similar to those of ageing.

Systemic inflammatory load in young and old ringdoves is modulated by consumption of a Jerte Valley cherry-based product.

A chronic subclinical inflammatory status that coexists with immune dysfunction is commonly found in the elderly population. Consumption of foods rich in antioxidants (e.g., cherries) is an attractive strategy to reduce risk from chronic diseases. Based on previous studies showing the antioxidant effect of a Jerte Valley cherry derivative product in humans, the objective of this work was to evaluate the effect of the intake of a Jerte Valley cherry-based beverage on inflammatory load in both young and old ringdoves (Streptopelia risoria). To this purpose, circulating levels of pro-inflammatory and anti-inflammatory cytokines as well as serum levels of different acute-phase proteins were measured before and after a 10-day treatment with the Jerte Valley cherry-based beverage. Thus, the 10-day treatment with the cherry-based beverage modulated the balance of pro- and anti-inflammatory cytokines in both young and old ringdoves by down-regulating the levels of pro-inflammatory cytokines (interleukin [IL]-1ß, tumor necrosis factor-α, and interferon-γ) and up-regulating the levels of anti-inflammatory cytokines (IL-4, IL-2, and IL-10). Moreover, the 10-day treatment with the Jerte Valley cherry-based product reduced the levels of several proteins involved in acute-phase responses, such as C-reactive protein, haptoglobin, α(2)-macroglobulin, and serum amyloid P component. On the other hand, old birds showed imbalanced levels of inflammatory markers toward a pro-inflammatory status, thereby underlining the fact that aging is usually accompanied by systemic inflammation and inflammation-related chronic diseases. To sum up, the data suggest a potential health benefit by consuming the cherry-based beverage, especially in aged populations, through their anti-inflammatory properties.

Improving the quality of infant sleep through the inclusion at supper of cereals enriched with tryptophan, adenosine-5'-phosphate, and uridine-5'-phosphate.

The present study evaluated whether the administration of cereals enriched with nutrients that are facilitators of sleep could help improve the sleep of infants who had sleep disorders at night time. Thirty infants aged 8-16 months with sleep disorders involving at least three nocturnal waking episodes took part in the study. They were given a night-time 'sleep facilitating cereal' product containing 225 mg tryptophan, 5.3 mg adenosine-5'-P, and 6.3 mg uridine-5'-P per 100 g of product. These cereals were given in a double-blind procedure lasting 5 weeks, with ingestion of the cereal between 18:00 and 06:00. In the control week, the children received a standard cereal (75 mg tryptophan/100 g product without nucleotides) dissolved in a standard formula milk (231.5 mg tryptophan, 2.6 mg adenosine-5'-P, 5 mg uridine-5'-P, per 100 g product). In one experimental week, the children received the night-time sleep facilitating cereal together with the standard formula milk. In another week, they received the sleep facilitating cereal together with a night milk specially formulated to attain the sleep rhythm (480 mg tryptophan, 8.8 mg uridine-5'-P, and 7.6 mg adenosine-5'-P per 100 g product). The three experimental weeks were separated by two wash-out weeks in which the milk and cereal administered was identical in composition to that of the control week. All the infants received a programmed writer actimeter which they wore continually, attached to their ankles, to record their motor activity. The recorded activity was used to calculate information about the time in bed, assumed sleep, actual sleep, sleep efficiency, sleep latency, immobility, and total activity. The infants receiving the enriched cereal during the time of darkness showed improvements in their sleep parameters, regardless of whether the milk they took at night was standard or enriched with tryptophan, adenosine-5'-P, and uridine-5'-P. In summary, the administration of enriched cereals led to an improvement in sleep, regardless of the type of infant milk used. These results support the concept of chrononutrition since they confirm that the sleep/wake rhythm can be influenced by diet.

Selenium modulates oxidative stress-induced cell apoptosis in human myeloid HL-60 cells through regulation of calcium release and caspase-3 and -9 activities.

Selenium is an essential chemopreventive antioxidant element to oxidative stress, although high concentrations of selenium induce toxic and oxidative effects on the human body. However, the mechanisms behind these effects remain elusive. We investigated toxic effects of different selenium concentrations in human promyelocytic leukemia HL-60 cells by evaluating Ca(2+) mobilization, cell viability and caspase-3 and -9 activities at different sample times. We found the toxic concentration and toxic time of H(2)O(2) as 100 microM: and 10 h on cell viability in the cells using four different concentrations of H(2)O(2) (1 microM: -1 mM: ) and six different incubation times (30 min, 1, 2, 5, 10, 24 h). Then, we found the therapeutic concentration of selenium to be 200 nM: by cells incubated in eight different concentrations of selenium (10 nM: -1 mM: ) for 1 h. We measured Ca(2+) release, cell viability and caspase-3 and -9 activities in cells incubated with high and low selenium concentrations at 30 min and 1, 2, 5, 10 and 24 h. Selenium (200 nM: ) elicited mild endoplasmic reticulum stress and mediated cell survival by modulating Ca(2+) release, the caspases and cell apoptosis, whereas selenium concentrations as high as 1 mM: induced severe endoplasmic reticulum stress and caused cell death by activating modulating Ca(2+) release, the caspases and cell apoptosis. In conclusion, these results explained the molecular mechanisms of the chemoprotective effect of different concentrations of selenium on oxidative stress-induced apoptosis.

Exercise-induced stress enhances mammary tumor growth in rats: beneficial effect of the hormone melatonin.

We hypothesized that intense exercise training (forced swimming for 30 min, 5 days/week) may enhance the progression of mammary carcinogenesis through the involvement of stress hormones, such as catecholamines and prolactin, which can promote breast cancer. After the appearance of the DMBA-induced tumors in Sprague-Dawley rats, the effect was evaluated of exercise-induced stress (with or without administration of the hormone melatonin) on the survival time, tumor multiplicity, and tumor growth until the death of the animals. In a second set of experiments, after one month of exercise, the NK cells count in blood, and the plasma concentrations of catecholamines and prolactin were determined. Although no significant change was found in either the survival time of the rats or the tumor multiplicity, exercise significantly increased the tumor growth rate. Stress was confirmed by the enhanced adrenaline and prolactin concentrations in the blood of the exercised rats. Exercise-induced stress did not change the percentage of NK cells in the tumor-bearing rats. Melatonin counteracted the increased tumor growth, returning the prolactin and adrenaline concentrations to their optimal physiological levels in the exercised tumor-bearing rats, thus confirming an "anti-stress" role of this hormone. In conclusion, intense exercise-induced stress enhances mammary carcinogenesis through the involvement of adrenaline and prolactin. The results also confirmed a role of melatonin as a therapeutic aid against breast cancer in general, and in particular during situations of stress.

Effect of orally administered L-tryptophan on serotonin, melatonin, and the innate immune response in the rat.

To assess the effects of external administration of L-tryptophan on the synthesis of serotonin and melatonin as well as on the immune function of Wistar rats, 300 mg of the amino acid were administered through an oral cannula either during daylight (08:00) or at night (20:00) for 5 days. Brain, plasma, and peritoneal macrophage samples were collected 4 h after the administration. The accumulation of 5-hydroxytryptophan (5-HTP) after decarboxylase inhibition was used to measure the rate of tryptophan hydroxylation in vivo. Circulating melatonin levels were determined by radioimmunoassay, and the phagocytic activity of macrophages was measured by counting, under oil-immersion phase-contrast microscopy, the number of particles ingested. The results showed a diurnal increase (p < 0.05) in the brain 5-HTP, serotonin (5-hydroxytryptamine, 5-HT), and 5-hydroxyindolacetic acid (5-HIAA) of the animals which had received tryptophan at 08:00 and were killed 4 h later. In the animals which received tryptophan during the dark period, the 5-HT declined but the 5-HT/5-HIAA ratio remained unchanged. There was also a significant increase (p < 0.05) in nocturnal circulating melatonin levels and in the innate immune response of the peritoneal macrophages in the animals which had received tryptophan at 20:00. The results indicated that the synthesis of serotonin and melatonin, as well as the innate immune response, can be modulated by oral ingestion of tryptophan.

Effect of stress and dexamethasone treatment on circadian rhythms of melatonin and corticosterone in ring dove (Streptopelia risoria).

The possible relationship between the circadian rhythm of blood levels of melatonin and corticosterone in ring dove (Streptopelia risoria) subjected to both immobilization stress and immobilization stress plus dexamethasone treatment were studied. The results show changes in the circadian rhythm of melatonin, with increased daytime levels in situations of stress accompanied by increased corticosterone levels. The highest blood melatonin levels over the 24 h of the study were obtained when the animals were treated with dexamethasone and then subjected to stress. Given the antioxidant role of melatonin, our results support the idea ofmelatonin-corticosterone coupling with the possibility that melatonin released in situations of stress counteracts the adverse effects of glucocorticoids on the organism.