Altitude effect on sleep quality and serum melatonin levels in Chilean mining workers / Efecto de la Altitud en la calidad de sueño y niveles séricos de melatonina en trabajadores mineros en Chile

High altitude (HA) mining operations are a very important business in Chile, but reduced availability of oxygen affects the sleep quality, increasing the risk of accidents. An important regulator of sleep-wake cycle is the hormone Melatonin, produced by pineal gland as a sleep inductor. The aim of this study is to evaluate the effect of high altitude (4,500 m) on the quality of sleep of workers undergoing to Chronic Intermittent Hypobaric Hypoxia (CIHH) using self-reported surveys of sleepiness and sleep quality, measurement of sleep apnea (using nocturnal oximetry) and serum levels of melatonin. The Desaturation index (ID4) results revealed higher HA scores compared to sea level (SL). Regarding melatonin levels, the results show that it is increased in HA versus SL and this increase would be related to oxygen saturation during sleep. These data link sleep quality in HA to its melatonin levels, suggesting that melatonin may be a potential biomarker for sleep quality.

Repercussions of melatonin on the risk of breast cancer: a systematic review and meta-analysis

SUMMARY Breast Cancer is common in women, but its etiology is not yet fully understood. Several factors may contribute to its genesis, such as genetics, lifestyle, and the environment. Melatonin may be involved in the process of breast cancer. Therefore, the aim of this study is to evaluate the influence of the levels of melatonin on breast cancer through a systematic review and meta-analysis. We performed a systematic review according to PRISMA recommendations. The primary databases MEDLINE, Embase, and Cochrane were consulted. There was no restriction on the year of publication and language. Data of systematic reviews from April 2017 to September to 2017 were analyzed. The meta-analysis was conducted using RevMan 5.3 software provided by the Cochrane Collaboration. From a total of 570 articles, 9 manuscripts were included in this review. They analy onzed women with breast cancer and control patients, of which 10% and 90% were in the reproductive period and after menopause, respectively. The lowest level of melatonin was found in approximately 55% of studies with breast cancer in post-menopause. The metanalyses of the studies demonstrated low levels of melatonin in breast cancer patients (n=963) compared with control patients (n= 1332), with a mean difference between the studies of 8722;3.54 (CI8722;6.01,8722;1.06). Another difference found was in the comparison between smoking patients, with an average difference between 1.80 [0.97-2.63]. Our data suggest that low levels of melatonin might be a risk factor for breast cancer.

RESUMO O câncer de mama é comum em mulheres, mas sua etiologia ainda não é totalmente compreendida. Vários fatores podem contribuir para sua gênese, genética, estilo de vida e meio ambiente. A melatonina pode estar envolvida no processo de câncer de mama. Portanto, o objetivo deste estudo é avaliar a influência dos níveis de melatonina no câncer de mama por meio de uma revisão sistemática e meta-análise. Realizamos uma revisão sistemática de acordo com as recomendações do Prisma. Os principais bancos de dados, Medline, Embase e Cochrane, foram consultados. Não houve restrição quanto ao ano de publicação e idioma. Os dados de revisão sistemática obtidos de abril de 2017 a setembro a 2017 foram analisados. A meta-análise foi conduzida pelo programa RevMan 5.3 fornecido pela Cochrane Collaboration. De um total de 570 artigos, nove foram incluídos nesta revisão. As análises foram conduzidas em mulheres com câncer de mama e pacientes controle, dos quais 10% e 90% estavam no período reprodutivo e após a menopausa, respectivamente. O nível mais baixo de melatonina foi encontrado em aproximadamente 55% dos estudos com câncer de mama na pós-menopausa. As meta-análises de estudos demonstraram os baixos níveis de melatonina em doentes com câncer da mama (n=963), em comparação com os pacientes de controle (n=1.332), sendo a diferença de médias entre os estudos da 8722;3,54 (CI 8722;6,01, 8722;1,06). Outra diferença é demonstrada nas comparações entre pacientes fumantes, sendo a diferença da média entre 1,80 [0,97-2,63]. Nossos dados sugerem que baixos níveis de melatonina podem ser um fator de risco para câncer de mama.

Serum levels of melatonin may contribute to the pathogenesis of heart failure in children with median age of 1 year / Níveis séricos da melatonina podem contribuir para a patogênese de insuficiênciacardíaca em crianças com idade média de 1 ano

Abstract Objective: Melatonin has a protective role in adults with cardiovascular disease, but the effects of melatonin in children with cardiac dysfunction are not well understood. This study was designed to explore the variations in melatonin, myeloperoxidase, and caspase-3 levels in children suffering from heart failure. Methods: Seventy-two pediatric patients with heart failure and twelve healthy children were enrolled in this study. A modified Ross scoring system was used to evaluate clinical cardiac function. Patients with a score of >2 points were included in the study and were divided into three groups according to severity of heart failure: mild (score: 3-6), moderate (score: 7-9), and severe (score: 10-12). Echocardiographic parameters, laboratory data, and serum levels of melatonin, myeloperoxidase, and caspase-3 were measured and analyzed in all patients. Results: Compared with patients with mild and moderate heart failure, patients in the severe heart failure group had significantly decreased left ventricular ejection fraction (p < 0.001), and significantly increased serum melatonin levels (p = 0.013) and myeloperoxidase levels (p < 0.001). Serum melatonin levels were positively correlated with serum caspase-3 levels (p < 0.001). The optimal cutoff values of serum melatonin levels for the diagnosis of severe heart failure and primary cardiomyopathy in pediatric patients with heart failure were 54.14 pg/mL and 32.88 pg/mL, respectively. Conclusions: Serum melatonin and myeloperoxidase levels were increased in children with severe heart failure. It is likely that increasing melatonin levels may act as a compensatory mechanism in pediatric children with heart failure.

Resumo Objetivo: A melatonina possui um papel protetor em adultos com doença cardiovascular, porém os efeitos da melatonina em crianças com disfunção cardíaca não são bem entendidos. O estudo foi projetado para explorar a variação nos níveis de melatonina, mieloperoxidase e caspase 3 em crianças que sofrem de insuficiência cardíaca. Métodos: 72 pacientes pediátricos com insuficiência cardíaca e 12 crianças saudáveis foram inscritos no estudo. Um sistema de classificação de Ross modificada foi utilizado para avaliar a função cardíaca clínica. Os pacientes com escore de > 2 pontos foram incluídas no estudo e foram divididos em três grupos de acordo com a gravidade da insuficiência cardíaca: leve (escore: 3-6), moderada (escore: 7-9) e grave (escore: 10-12). Os parâmetros ecocardiográficos, dados laboratoriais e níveis séricos de melatonina, mieloperoxidase e caspase 3 foram medidos e analisados em todos os pacientes. Resultados: Em comparação com os pacientes com insuficiência cardíaca de gravidade leve e moderada, os pacientes no grupo de insuficiência cardíaca grave apresentaram redução significativa da fração de ejeção do ventrículo esquerdo (p < 0,001) e aumento significativo nos níveis séricos de melatonina (p = 0,013) e níveis de mieloperoxidase (p < 0,001). Os níveis séricos de melatonina foram positivamente correlacionados com os níveis séricos de caspase 3 (p < 0,001). Os valores de corte ideais dos níveis séricos de melatonina para diagnóstico de IC e cardiomiopatia primária em pacientes pediátricos com insuficiência cardíaca foram 54,14 pg/mL e 32,88 pg/mL, respectivamente. Conclusões: Os níveis séricos de melatonina e mieloperoxidase mostraram aumento em crianças com insuficiência cardíaca grave. Especulamos se o aumento nos níveis de melatonina pode agir como um mecanismo compensatório em crianças pediátricas com insuficiência cardíaca.

Low serum melatonin levels are associated with erectile dysfunction

ABSTRACT Objective: Melatonin is a hormone secreted from the pineal gland and has anti-oxidative and anti-inflammatory effects. Oxidative stress is considered as an important factor in the etiology of erectile dysfunction (ED), and in many experimental models, positive results have been obtained with melatonin treatment. This study aimed to measure serum melatonin levels in ED patients and to investigate the possible relationship between ED and melatonin levels. Materials and Methods: Sixty-two patients diagnosed with mild, moderate or severe ED according to the five-item International Erectile Function Index (IIEF-5) and 22 healthy individuals were included in the study. The serum melatonin levels, anthropometric data, and other biochemical and hormonal parameters of all the subjects were recorded. Detailed anamnesis was also obtained in terms of diabetes, hypertension, cardiovascular diseases, smoking status, and alcohol use. Results: The serum melatonin level was found 34.2±13.3 ng/dL in the mild ED group, 33.3±14.7 ng/dL in the moderate ED group, 34.8±17.2 ng/dL in the severe ED group, and 44.6±16.5 ng/dL in the control group. The serum melatonin levels were significantly lower in all ED groups compared to the control group (p=0.019). There was no significant difference in the serum melatonin levels between the three ED groups. Diabetes, hypertension, cardiovascular diseases, smoking and alcohol use were not significantly different between the ED groups (p>0.05). Conclusion: We consider that if our findings are supported by further studies with larger populations, the measurement of the serum melatonin level may have a future role in the diagnosis and treatment of ED.

Outline of changes in cortisol and melatonin circadian rhythms in the security guards of Shiraz University of Medical Sciences

According to the literature, a large number of people working in industries and service providing personnel, such as firefighters, physicians, and nurses are shift workers. The spread of shift working in industrial societies and the incidence of the problems resulting from shift working have caused the researchers to conduct studies on this issue. The present study also aimed to investigate melatonin and cortisol circadian rhythms in the security guards of Shiraz University of Medical Sciences, Shiraz, Iran. The present study was conducted on 20 security guards of Shiraz University of Medical Sciences. In order to collect the study data, blood samples were taken from the study subjects in different times of the day [1, 4, 7, 10, 13, 16, 19, and 22] and cortisol and melatonin levels were determined using the radioimmunoassay and enzyme immunoassay techniques, respectively. The results showed that as the intensity of light increased at night, the plasma cortisol level increased, as well. Besides, no statistically significant difference was found between the plasma cortisol levels in natural light and 4500-lux light. On the other hand, a significant difference was observed between the plasma cortisol levels in natural light and 9000-lux light as well as 4500- and 9000-lux lights. The study findings also showed that as the intensity of light increased at night, the plasma melatonin level decreased. In addition, a statistically significant difference was found between the plasma melatonin levels in natural light and 4500-lux light. Nevertheless, no significant difference was observed between the plasma melatonin levels in the natural light and 9000-lux light as well as 4500- and 9000-lux lights. The present study aimed to investigate the subsequences of shift working in the security guards of Shiraz University of Medical Sciences and showed that occupational exposure to bright light could affect some biological markers, such as melatonin and cortisol secretion

Morning and nocturnal serum melatonin rhythm levels in patients with major depressive disorder: an analytical cross-sectional study / Medir los niveles del ritmo de melatonina día-noche entre los pacientes con trastorno depresivo mayor: un estudio analítico transversal

CONTEXT AND OBJECTIVE: The pineal gland is an adaptive organ that precisely regulates the biological rhythms of melatonin brain hemostasis. Variation in the regulation of melatonin rhythms is a likely cause of depressive disorder. The purpose of this study was to measure serum melatonin levels in patients with major depressive disorder (MDD) and normal control subjects. DESIGN AND SETTING: Analytical cross-sectional study at the industrial medical unit of the Iron Smelting Company of Isfahan, Iran. METHODS: The morning and nocturnal serum melatonin levels of patients and controls were measured using the enzyme-linked immunosorbent assay (ELISA) method. All data were assessed using variance analysis. RESULTS: The morning and nocturnal serum melatonin levels of depressed and healthy subjects differed (P < 0.05). The nocturnal serum melatonin levels of depressed women were lower than those of depressed men (P < 0.05). CONCLUSIONS: The findings of this study showed that the nocturnal serum melatonin levels in the depressed patients were lower than in the controls. Thus, the peak melatonin phase in the depressed patients was reached with delay. CLINICAL TRIAL REGISTRATION NUMBER: NCT01357083.

CONTEXTO Y OBJETIVO: La glándula pineal actúa precisamente regulando los ritmos biológicos de melatonina de hemostasia cerebral, como un órgano adaptativo. La modificación del ritmo de melatonina puede ser el motivo probable del trastorno depresivo. Este estudio se realizó con el objetivo de medir los niveles de melatonina entre los pacientes con trastorno depresivo mayor y los sanos. DISEÑO Y ESPACIO: Estudio analítico transversal-la unidad medicina laboral de empresa de Zob Ahan de Isfahán-Irán. MÉTODO: Los niveles de melatonina en suero día-noche se midó entre dos grupos (pacientes y sanos) utilizando el método de ELISA (Ensayo por inmunoabsorción ligado a enzimas). Todos los datos se hizo utilizando el análisis de la varianza. RESULTADOS: El nivel de melatonina en suero día-noche era distinto entre los deprimidos y los saludables (P < 0.05). El nivel de melatonina en suero en las mujeres deprimidas fue menos que los varones deprimidos (P < 0.05). CONCLUSIONES: Esta investigación muestra que el nivel de melatonina nocturna en los deprimidos ha sido menos que los controlados, pues el pico de fase de melatonina en los pacientes deprimidos alcanza con retraso. NÚMERO DE REGISTRO DE ENSAYO CLÍNICO: NCT01357083.

Abnormality of Circadian Rhythm of Serum Melatonin and Other Biochemical Parameters in Fibromyalgia Syndrome.

Fibromyalgia syndrome (FMS) is a complex chronic condition causing widespread pain and variety of other symptoms. It produces pain in the soft tissues located around joints throughout the body. FMS has unknown etiology and its pathophysiology is not fully understood. However, abnormality in circadian rhythm of hormonal profiles and cytokines has been observed in this disorder. Moreover, there are reports of deficiency of serotonin, melatonin, cortisol and cytokines in FMS patients, which are fully regulated by circadian rhythm. Melatonin, the primary hormone of the pineal gland regulates the body’s circadian rhythm and normally its levels begin to rise in the mid-to-late evening, remain high for most of the night, and then decrease in the early morning. FMS patients have lower melatonin secretion during the hours of darkness than the healthy subjects. This may contribute to impaired sleep at night, fatigue during the day and changed pain perception. Studies have shown blunting of normal diurnal cortisol rhythm, with elevated evening serum cortisol level in patients with FMS. Thus, due to perturbed level of cortisol secretion several symptoms of FMS may occur. Moreover, disturbed cytokine levels have also been reported in FMS patients. Therefore, circadian rhythm can be an important factor in the pathophysiology, diagnosis and treatment of FMS. This article explores the circadian pattern of abnormalities in FMS patients, as this may help in better understanding the role of variation in symptoms of FMS and its possible relationship with circadian variations of melatonin, cortisol, cytokines and serotonin levels.

Different intensities of treadmill running exercise do not alter melatonin levels in rats / Diferentes intensidades de exercício de corrida em esteira não alteram os níveis de melatonina em ratos

Background: Regular and moderate exercise has been considered an interesting neuroprotective strategy. Our research group demonstrated that a protocol of moderate exercise on a treadmill reduced, while a protocol of high-intensity exercise increased in vitro ischemic cell damage in Wistar rats. The molecular mechanisms by which physical exercise exerts neuroprotective effects remain unclear. Accumulating evidence suggests that exercise may have short- and long-term effects on melatonin secretion in humans. Melatonin, the main product of the pineal gland, has been shown to have neuroprotective effects in models of brain and spinal cord injury and cerebral ischemia. A dual modulation of melatonin secretion by physical activity has also been demonstrated. This study aimed to investigate the effect of different exercise intensities, moderateand high-intensity exercise, on serum melatonin levels in rats. Methods: Thirty-five adult male Wistar rats were divided into non-exercised (sedentary) and exercised (20- or 60-min sessions) groups. The exercise protocols consisted of two weeks of daily treadmill training. Blood samples were collected approximately 16 hours after the last training session (8:00-10:00) and melatonin levels were assayed by ELISA. Results: The exercise protocols, two weeks of 20 min/day or 60 min/day of treadmill running, did not affect serum melatonin levels. Conclusion: Our data demonstrated that melatonin levels may not be directly involved in the exercise-induced, intensitydependent dual effect on in vitro ischemia.

Introdução: O exercício físico regular e moderado é considerado uma interessante estratégia neuroprotetora. Nosso grupo de pesquisa demonstrou que um protocolo de exercício moderado em esteira reduziu, enquanto um protocolo de intensidade elevada aumentou o dano isquêmico in vitro em ratos Wistar. Os mecanismos moleculares pelos quais o exercício físico exerce neuroproteção ainda não estão claramente elucidados. Várias evidências sugerem que o exercício pode ter efeitos a curto e longo prazo sobre a secreção de melatonina em humanos. A melatonina, o principal produto da glândula pineal, tem demonstrado exercer uma atividade neuroprotetora em modelos de trauma cerebral e medular e isquemia cerebral. Foi demonstrada também uma modulação dual da atividade física sobre a secreção de melatonina. O objetivo deste estudo foi estudar o efeito de diferentes intensidades de exercício, moderado e elevado, sobre os níveis séricos de melatonina de ratos. Métodos: Trinta e cinco ratos Wistar adultos machos foram divididos em não-exercitados (sedentários) ou exercitados (sessões de 20 ou 60 min). Os protocolos de exercício consistiam em duas semanas diárias de treinamento em esteira ergométrica. Os soros foram coletados aproximadamente 16 horas após a última sessão de treino (8:00-10:00) e os níveis de melatonina foram avaliados através da técnica de ELISA. Resultados: Os protocolos de exercício físico, duas semanas de 20 min/dia ou 60 min/dia de corrida em esteira, não alteraram os níveis séricos de melatonina. Conclusão: Nossos dados demonstram que os níveis de melatonina parecem não estar diretamente envolvidos com o efeito dual do exercício físico dependente da intensidade na isquemia in vitro.

Effect of moderate exercise on the level of melatonin hormone and lymphocyte apoptosis in healthy subjects

Physical exercise is important for promotion of the immune system. The immune responses to exercise are dependent on the intensity and duration of the exercise performed. During exercise, metabolic and hormonal changes occurred that can induce lymphocyte apoptosis. Melatonin is one of the hormones that are affected by exercise, it is a pineal gland hormone, its production and secretion followed a circadian pattern, onset of darkness stimulate its secretion, while day light suppress its production. Melatonin is regarded as an anti-aging hormone; it has a role in the elimination of harmful lymphocytes which may give rise to chronic inflammation and possibly to autoimmunity. This prospective study aimed to elucidate the effect of moderate endurance exercise on melatonin hormone and the percentage of peripheral blood lymphocyte apoptosis in healthy subjects. Sixty healthy subjects with a mean age of [37.05 +/- 13.02] year, participated in the study. They were subjected to moderate exercise session which lasted for 60 min and repeated 3 times per week for 3 months. The exercise intensity was 50-60% of heart rate reserve [according to Karvonen formula]. Two exercise stages were performed; the first stage include 30 minute of physical activity program and the second stage include 30 minute of treadmill exercise. Blood sample were collected before and after exercise to examine its effect on the level of melatonin hormone and apoptosis of peripheral blood lymphocyte. This study showed significant increment in the level of melatonin hormone and the percentage of lymphocyte apoptosis after exercise in comparison to pre exercise values for each week along the period of the test [P < 0.05]. Three months exercise showed a significant correlation with the levels of melatonin hormone [P= 0.008, r= 0.44], and with percentage of lymphocyte apoptosis [P = 0.001, r= 0.701]. It can be concluded that moderate exercise for three months was associated with increased percentage of periphral blood lymphocyte apoptosis and increased level of melatonin hormone in the first two months while in the third month this anti aging hormone had reached a steady state after the subjects get trained to exercise

A reverse phase high performance liquid chromatography method for simultaneous estimation of melatonin, carbamazepine epoxide and carbamazepine simultaneously in serum.

Monitoring of plasma antiepileptic drugs is useful for better clinical management in epileptic patients, particularly in children. Carbamazepine (CBZ) is one of the commonly prescribed anticonvulsants. The active metabolite of carbamazepine-carbamazepine-10-11 epoxide (CBZ-Epo) also exhibits anticonvulsant effect. The pineal hormone, melatonin exerts an anticonvulsant effect in experimental seizure models and recently has also been used in cases of childhood epilepsy. To facilitate the simultaneous plasma estimation of carbamazepine, carbamazepine epoxide, and melatonin, a new HPLC method was developed. Waters millennium 2010 chromatography manager with a 515 HPLC pump and Waters 24879 dual absorbance UV detector was used. A 25 microlitre of sample and standards were injected, and chromatographic separation was achieved by Merck C18 reverse phase column particle size 5 micro, 250 mm x 4 mm. It was quantitated at UV light 210 nm. The retention times of melatonin, CBZ-Epo, and CBZ were 6.3 min, 7.5 min, and 13.9 min respectively. The Mobile Phase used was water: acetonitrile (70:30), pH 3.0 adjusted with orthophosphoric acid at the flow rate of 1 ml/min. The limits of detection of melatonin, carbamazepine epoxide, and carbamazepine were 800, 500, and 1300 pg respectively.

A study of the effects of pinealectomy on intestinal cell proliferation in infant newborn rats

OBJETIVO: Estudar a taxa de proliferação celular no jejuno e nas células epiteliais das criptas do intestino grosso em ratos pinealectomizados imediatamente após o nascimento. MÉTODOS: 24 ratos machos Wistar foram divididos em dois grupos. Grupo agudo (n=12) e Grupo Crônico (n=12). Seis animais de cada grupo foram operados para remover-se a glândula pineal (Pinealectomia-PnX), e outros seis animais foram controle (sham pinealectomia-C). Os animais de ambos os grupos foram sacrificados 15 e 90 dias após a cirurgia, respectivamente. RESULTADOS: No grupo agudo, a pinealectomia dos ratos não causou alterações significativas na proliferação celular (PnX=58,77±1,77 e C=60,88±1,10 no cólon descendente / PnX=31,56±0,45 e C=31,73±0,47 no jejuno proximal) e na população celular de criptas (PnX=24,92±4,82 e C=23,60±2,48 no cólon descendente / PnX=39,92±3,49 e C=44,32±5,56 no jejuno proximal). Contudo, no grupo crônico houve aumento na proliferação celular das criptas no jejuno proximal (PnX=57,54±2,19 e C=47,19±7,3), e no cólon descendente (PnX=37,78±2,22 e C=17,92±2,28). CONCLUSAO: Como o aumento epitelial celular das criptas intestinais no grupo crônico pode ser avaliado como fator predeterminante da carcinogênese, faz-se necessário o conhecimento da interação entre esta glândula e este evento.

Seasonal mood disorders

Depending on occurrence of recurrence of mood disorder in specific seasons, it is classified as non- seasonal or seasonal mood disorder. Although there is no place for seasonal mood disorder in the classification of mental disorders, many studies have proved that seasonal mood disorder has distinguishing features from non-seasonal mood disorder

The effect of antidepressants on serum melatonin levels in endogenous depression.

OBJECTIVES: 1. To assess the serum melatonin levels in patients suffering from endogenous depression and the effect of pharmacological therapy. 2. To establish possible correlation between the height from the mean sea levels and the patients suffering from endogenous depression. METHODS: Forty patients, 18 males and 22 females, suffering from endogenous depression (according to DSM IV criteria), aged 48.3 +/- 12.32 years were evaluated and serum melatonin level was assayed between 9-10 am. They were not on any drugs/medication, which was likely to alter serum melatonin level for one month prior to study. The serum melatonin levels were assessed at 0, 3, 6 and 12 months while they were continued to be treated. It also included 30 controls of the matched age and sex and satisfying the inclusion criteria. The possible correlation was also studied between the serum levels and the height from the mean sea level at which the patients reside. RESULTS: The two groups were comparable at the beginning of the study. The serum melatonin levels started falling from three months onwards (from 9.99 +/- 3.59 pg/nl to 8.49 +/- 3.16 pg/nl; p < 0.05). However, the decline was maximum between 3-6 months (from 8.49 +/- 3.16 to 5.589 +/- 1.96; p<0.05). The serum levels became stationary beyond six months. Highest melatonin levels were observed in patients residing at an altitude of 6001-8000 metres (14.32 +/- 2.68 pg/ml; p < 0.05) followed by 4,001-6,000 meters (11.137 +/- 2.62 pg/ml; p < 0.05). However, the levels were almost stationary below 4,000 metres (p = 0.05). CONCLUSION: 1. Higher serum melafonin values were observed in patients suffering from endogenous depression. 2. Morning serum melatonin values decreased with pharmacological therapies. 3. Patients living at higher altitudes had higher serum values for the hormone.

Rotating shift work and disruption of biological rhythms as indicated by serum melatonin, prolactin and cortisol

Rotating shift work is associated with many health problems due to disruption of the biological rhythms. Melatonin, prolactin and cortisol serum levels were measured for 50 nurses working under rotating shift system and 65 nurses working only during daytime to assess the impact of rotating shift work on the circadian rhythms. Our results revealed that serum melatonin was significantly lower among rotators compared to day-shift workers while prolactin and cortisol levels were significantly higher. Serum melatonin showed a significant negative correlation with both duration of service and worker's age. On the other hand levels of prolactin and cortisol demonstrated a significant positive correlation with both parameters. Designing appropriate scheduling of shift work with proper consideration of the speed of shift rotation is recommended

Profile of organ weights and plasma concentrations of melatonin, estradiol and progesterone during gestation and post-parturition periods in female Indian palm squirrel Funambulus pennanti.

Todate, report about the role of pineal gland in maintaining the normal physiology of gestation is scanty. Present study is the first of its kind giving a detail profile of organ weights and plasma concentration of melatonin, estradiol and progesterone to suggest a possible role of pineal gland in maintaining normal physiology during gestation and post-parturition periods of female Indian palm squirrel F. pennanti. Inspite of, inverse pineal-gonadal/melatonin-steroids interrelationship in adult (non-pregnant) females, the present results study suggest a direct relationship of pineal gland activity with ovarian steroids especially during the gestation period. The inverse relationship of melatonin and ovarian steroids is again established after parturition and maintained throughout the life. Thus the pineal gland (activity as judged by its weight, biochemical contents i.e. protein and cholesterol and plasma melatonin level) maintained ovarian/uterine physiology and regulated plasma concentrations of estradiol and progesterone during gestation and post-parturition periods. It is suggested that the pineal gland and its hormone melatonin play an important role to maintain the normal physiology of gestation and the post-partum recovery in Indian palm squirrel F. pennanti.

Serum melatonin rhythms and prolactin levels in workers exposed to electeomagnetic fields around high voltage electric power lines

One of the more contentious issues in the scientific community today is that of the biological effects of electromagnetic fields [EMFs] and whether or not they adversely affect our health. Many authors studied the effect of EMFs on melatonin and prolactin serum levels. Our results revealed a significant reduction of serum melatonin levels and an increase in prolactin secretion in workers exposed to EMFs around high voltage power lines. A significant correlation was detected between the reduction in serial measurements of melatonin levels and the strength of electric fields, while no such correlation was detected concerning prolactin level. Although negative correlation was found between serial melatonin levels and duration of exposure, yet it was not significant. Previous studies reported that reduction of melatonin increases cell vulnerability to alteration by carcinogenic agents. Concerning prolactin, no such correlation was detected. We recommended periodic screening tests for early detection of cancer in high risk workers

serum melatonin level and cognitive dysfunction in patients with liver cirrhosis

The mechanism of hepatic encephalopathy are uncertain despite extensive studies. Recently, many studies have been done to find out the role of the melatonin hormone and its relation to many diseases especially liver cirrhosis. The present study was designed to detect the change in serum melatonin level in patients with liver cirrhosis and its correlation with the clinical status of the patients and their cognitive functions. Seventeen patients with liver cirrhosis and 12 matched healthy controls were recruited in the study. They were subjected to clinical examination; abdominal ultrasonography; routine liver function tests and a battery of neuropsychological tests and EEG. Three venous blood samples were taken at 8 pm, 4 am and 8 am, from all patients and controls, for serum melatonin assay using ELISA kits. It was found that at 8 pm the mean serum melatonin level is significantly lower in patients than in controls, while at 4 am and 8 am the mean levels were significantly higher in patients than in controls; being at the highest level at 4 am. There was a positive significant correlation between the mean serum levels of melatonin at different times and the Child's grading of the patients. On the other hand, the patients with liver cirrhosis showed significantly abnormal results of the psychometric tests than controls. EEG was found to be slower in patients than controls as indicated by significantly slower alpha mean frequency. There was a significant positive correlation between the change in the serum melatonin level at 4 am and 8 am and the result of Bender- Gestalt test [a test of visual motor coordination]; a negative correlation between the performance on digit- symbol test [a test of attention / concentration and executive motor functions] and the serum melatonin level at 4 am. It could be suggested that the change in the serum melatonin level in patients with liver cirrhosis may have a role in the pathogenesis of the changes in the cognitive functions occurring in hepatic encephalopathy. Hypothetically, this might prove later on to have a therapeutic implication in the management of these patients

Diurnal variations in circulating estradiol, testosterone, melatonin and harderian gland porphyrin concentration in Indian palm squirrel, Funambulus pennanti.

A two-peak cyclicity in the plasma level of melatonin, estradiol/testosterone and Harderian porphyrin was noted in F. pennanti. An inverse relationship of Harderian porphyrin with plasma melatonin and a direct relation of it with plasma estradiol/testoserone level were also observed, suggesting that the variation of Harderian, porphyrin concentration may be under the control of both, circulating melatonin and gonadal steroids.

Melatonin, the hormone of the pineal body: its role as an endogenous biological marker in major depression and breast cancer

The present study was designed to assess the relation of melatonin to two important pathological conditions namely; major depression [MD] and breast cancer [BC], with the intention of evaluating its role as an endogenous biological marker of both conditions and its potential clinical significance in follow-up of such cases. For this purposes 50 female patients with major depression [20 patients before treatment and 30 patients under treatment] in addition to 73 female patients with breast cancer [28 in stages I and II : early BC; 25 in stages III and IV late BC and 20 after radical mastectomy] were chosen for assessment of the serum melatonin levels. Nocturnal blood samples were collected from the MD group. whereas morning samples were collected from the BC group. Results were compared to those of an age-matched control group consisting of 20 healthy females. Nocturnal serum melatonin levels were significantly decreased in MD patients before the start of therapy as compared to the control group [P < 0.0001]. Meanwhile, the results of patients under antidepressant therapy [monoamine oxidase inhibitors and tricyclic antidepressants] showed no significant difference from the control group [P>0.05]. In cases of cancer breast, morning serum melatonin levels were significantly decreased in the early stages of the disease [P<0.0001], but became significantly elevated with progress of cancer and the occurrence of metastasis [P<0.0001]. Following radical mastectomy, the level of melatonin was insignificantly different from the control group [P >0.05]. Hence, we can conclude that decreased nocturnal melatonin could be considered an endogenous marker of major depressive illness, with such a decrease being masked by antidepressant therapy. Meanwhile, morning melatonin levels are of value in assessment and staging of breast cancer as well as post-operative follow-up of these patients. hopefully, aiming at early detection of recurrence

Aspectos neuroendocrinos y psicofarmacologicos de la funcion pineal: melatonina y desordenes psiquiatricos / Neuroendocrine and psychopharmacological aspects of the pineal function: melatonin and psychiatric disorders

La presente revisión de la literatura especializada considera el paple fisiológico de la glándula pineal y su principal producto, la hormona melatonina, en los principapels cuadros psiquiátricos, como esquizofrenia, desórdenes afectivos y en algunas conductas básicas del animal y del hombre. Sin embargo, al presente, los mecanismos por los cuales la melatonina actúa a nivel fisiológico y farmacológico permanecen en muchos puntos como materia de especulación. Es, por ahora, imposible saber si el estudio sistemático de la pineal demostrará ser de significado en la comprensión de los desórdenes mentales; pero es, creemos, suficiente la evidencia que justifica tal interrogante