Pineal calcification in Alzheimer's disease: an in vivo study using computed tomography

An Expanded Narrative Review of Neurotransmitters on Alzheimer's Disease: The Role of Therapeutic Interventions on Neurotransmission

Alzheimer's disease (AD) is a progressive neurodegenerative disease. The accumulation of amyloid-β (Aβ) plaques and tau neurofibrillary tangles are the key players responsible for the pathogenesis of the disease. The accumulation of Aβ plaques and tau affect the balance in chemical neurotransmitters in the brain. Thus, the current review examined the role of neurotransmitters in the pathogenesis of Alzheimer's disease and discusses the alterations in the neurochemical activity and cross talk with their receptors and transporters. In the presence of Aβ plaques and neurofibrillary tangles, changes may occur in the expression of neuronal receptors which in turn triggers excessive release of glutamate into the synaptic cleft contributing to cell death and neuronal damage. The GABAergic system may also be affected by AD pathology in a similar way. In addition, decreased receptors in the cholinergic system and dysfunction in the dopamine neurotransmission of AD pathology may also contribute to the damage to cognitive function. Moreover, the presence of deficiencies in noradrenergic neurons within the locus coeruleus in AD suggests that noradrenergic stimulation could be useful in addressing its pathophysiology. The regulation of melatonin, known for its effectiveness in enhancing cognitive function and preventing Aβ accumulation, along with the involvement of the serotonergic system and histaminergic system in cognition and memory, becomes remarkable for promoting neurotransmission in AD. Additionally, nitric oxide and adenosine-based therapeutic approaches play a protective role in AD by preventing neuroinflammation. Overall, neurotransmitter-based therapeutic strategies emerge as pivotal for addressing neurotransmitter homeostasis and neurotransmission in the context of AD. This review discussed the potential for neurotransmitter-based drugs to be effective in slowing and correcting the neurodegenerative processes in AD by targeting the neurochemical imbalance in the brain. Therefore, neurotransmitter-based drugs could serve as a future therapeutic strategy to tackle AD.

Intracranial calcifications associated with factors related and unrelated to atherosclerosis in older people: A community dwelling cohort study

The cause of intracranial calcification is not fully understood. The aim of the current study was to identify factors associated with intracranial calcification and to determine whether these factors differ in calcification of different sites. A total of 404 community-dwelling people aged 65 or older were included in the study. All subjects underwent brain computed tomography (CT), blood tests, and a Mini-Mental State Examination (MMSE). Intracranial calcifications were scored using CT. Stepwise regression analysis was performed to examine factors associated with intracranial calcification, with each calcification score used as a dependent variable. Independent variables included age, gender, hemoglobin A1c (HbA1c), dyslipidemia, estimated glomerular filtration rate (eGFR), blood pressure, body mass index (BMI), smoking, serum iron, ferritin, and intact parathyroid hormone (PTH). Stepwise regression analysis detected male gender as a predictor of pineal gland calcification and intact PTH as a predictor of basal ganglia calcification. Age and lifestyle diseases were identified as predictors of calcification of the falx cerebri, internal carotid arteries, and vertebral arteries. These results indicate that the mechanisms of calcifications of the pineal gland and basal ganglia might differ from that of artery calcification, and that causes of intracranial calcification might be classified using factors that are and are not related to atherosclerosis.

Meditation Experience is Associated with Increased Structural Integrity of the Pineal Gland and greater total Grey Matter maintenance

Growing evidence demonstrates that meditation practice supports cognitive functions including attention and interoceptive processing, and is associated with structural changes across cortical networks including prefrontal regions, and the insula. However, the extent of subcortical morphometric changes linked to meditation practice is less appreciated. A noteworthy candidate is the Pineal Gland, a key producer of melatonin, which regulates circadian rhythms that augment sleep-wake patterns, and may also provide neuroprotective benefits to offset cognitive decline. Increased melatonin levels as well as increased fMRI BOLD signal in the Pineal Gland has been observed in mediators vs. controls. However, it is not known if long-term meditators exhibit structural change in the Pineal Gland linked to lifetime duration of practice. In the current study we performed Voxel-based morphometry (VBM) analysis to investigate: 1) whether long-term meditators (LTMs) (n=14) exhibited greater Pineal Gland integrity compared to a control group (n=969), 2) a potential association between the estimated lifetime hours of meditation (ELHOM) and Pineal Gland integrity, and 3) whether LTMs show greater Grey Matter (GM) maintenance (BrainPAD) that is associated with Pineal Gland integrity. The results revealed greater Pineal Gland integrity and lower BrainPAD scores (younger brain age) in LTMs compared to controls. Exploratory analysis revealed a positive association between ELHOM and greater signal intensity in the Pineal Gland but not with GM maintenance as measured by BrainPAD score. However, greater Pineal integrity and lower BrainPAD scores were correlated in LTMs. The potential mechanisms by which meditation influences Pineal Gland function, hormonal metabolism, and GM maintenance are discussed - in particular melatonin's roles in sleep, immune response, inflammation modulation, and stem cell and neural regeneration.

Protective Effect of the Novel Melatonin Analogue Containing Donepezil Fragment on Memory Impairment via MT/ERK/CREB Signaling in the Hippocampus in a Rat Model of Pinealectomy and Subsequent Aβ1-42 Infusion

A reduction in melatonin function contributes to the acceleration of Alzheimer's disease (AD), and understanding the molecular processes of melatonin-related signaling is critical for intervention in AD progression. Recently, we synthesized a series of melatonin analogues with donepezil fragments and tested them in silico and in vitro. In this study, one of the most potent compounds, 3c, was evaluated in a rat model of pinealectomy (pin) followed by icvAβ1-42 infusion. Melatonin was used as the reference drug. Treatment with melatonin and 3c (10 mg/kg, i.p. for 14 days) had a beneficial effect on memory decline and the concomitant increase in hippocampal Aβ1-42 and pTAU in the pin+icvAβ1-42 rats. Melatonin supplementation facilitated non-amyloidogenic signaling via non-receptor (histone deacetylase sirtuin 1, SIRT1) and receptor-related signaling (MT/ERK/CREB). The hybrid 3c analogue up-regulated the MT1A and MT2B receptors, pERK and pCREB. Our results strongly support the hypothesis that melatonin-related analogues may become a promising drug candidate for Alzheimer's disease therapy.

Prevalence and Clinical Significance of Incidental Findings in the Maxillofacial Complex of Adolescent Orthodontic Patients: A Retrospective Cone Beam Computed Tomography Analysis

OBJECTIVES

The aim of this study was to determine the prevalence and severity of incidental findings in the maxillofacial complex of orthodontic patients imaged with cone beam computed tomography (CBCT) and assign those findings an appropriate clinical significance.

METHODOLOGY

Incidental findings (IF) were identified in 250 CBCT scans of adolescent orthodontic patients (aged 13-18 years) with a large field-of-view and categorized based on their anatomic location and placed into one of six subgroups based on anatomic region: i) sino-nasal, ii) dentoalveolar, iii) nasooropharyngeal airway, iv) temporomandibular joint, v) neck, vi) calcifications, and vi) miscellaneous findings. Additionally, findings were assigned a clinical significance score based on severity on a scale of mild, moderate and severe. Mild IF was defined as an IF that does not require any further investigation or referral. Moderate IF was defined as an IF that has the tendency to become clinically significant and should be observed periodically. IFs that warrant further investigation and/or intervention were designated as severe.

RESULTS

The percentage of IFs in sino-nasal and dento-alveolar regions were 44.7% and 19.1% respectively. The percentage of IFs with mild, moderate, and severe clinical significance were 27%, 72%, and 1%, respectively. Out of the IFs involving calcifications, 80.8% were stylohyoid calcifications and <1% were cranial cavity IFs such as petroclinoid calcifications and falx cerebri calcifications. Among the sino-nasal findings, 1.2% were identified as severe.

CONCLUSION

The sino-nasal region had the highest frequency of IFs. Understanding the prevalence of incidental findings and its clinical relevance is important for clinicians to allow for appropriate monitoring and timely treatment of patients.

Micromorphology of pineal gland calcification in age-related neurodegenerative diseases

BACKGROUND

The formation of concrements in human pineal gland (PG) is a physiological process and, according to many researchers, is associated with the involution of PG structures. The majority of scientific publications concern progressive calcification of PG, leaving out studies on the destruction of already formed calcified concrements. Our study fills the gap in knowledge about calcified zones destruction in PG in normal aging and neuropathological conditions, which has not been addressed until now.

PURPOSE

Our objective is to gain insight into human PG tissue impairment in both normal aging and neurodegenerative conditions. X-ray phase-contrast tomography (XPCT) allowed us to study PG tissue degeneration at high spatial resolution and, for the first time, to examine the damaged PG concrements in detail. Our research finding could potentially enhance the understanding of the PG involvement in the process of aging as well as in Alzheimer's disease (AD) and vascular dementia (VD).

METHODS

The research was carried out on human PG autopsy material in normal aging, VD, and AD conditions. Laboratory-based micro-computed tomography (micro-CT) was used to collect and evaluate samples of native, uncut, and unstained PG with different degrees of pineal calcification. The detailed high-resolution 3D images of the selected PGs were produced using synchrotron-based XPCT. Histology and immunohistochemistry of soft PG tissue confirmed XPCT results.

RESULTS

We performed via micro-CT the evaluation of the morphometric parameters of PG such as total sample volume, calcified concrements volume, and percentage of concrements in the total volume of the sample. XPCT imaging revealed high-resolution details of age-related PG alteration. In particular, we noted signs of moderate degradation of concrements in some PGs from elderly donors. In addition, our analysis revealed noticeable degenerative change in both concrements and soft tissue of PGs with neuropathology. In particular, we observed a hollow core and separated layers as well as deep ragged cracks in PG concrements of AD and VD samples. In parenchyma of some samples, we detected wide pinealocyte-free fluid-filled areas adjacent to the calcified zones.

CONCLUSION

The present work provides the basis for future scientific research focused on the dynamic nature of PG calcium deposits and PG soft tissue in normal aging and neurodegenerative diseases.

Evaluation of prevalence and dimension of Pineal Gland Calcification by cone-beam computed tomography (CBCT)

Abstract Objective: This study aimed to investigate the prevalence and dimensions of pineal gland calcification using cone-beam computed tomography (CBCT) in patients undergoing dental treatment. Materials and Methods: CBCTs that localized pineal gland in the fov range was selected in this retrospective study. The presence of pineal gland calcification (PGC) was noted. Vertical, horizontal and areal measurements were made by a single observer (M.S). Variables such as age, gender for each patient were recorded using previous clinical examination data. Results: The prevalence of pineal gland calcification was 33.64% (female to male ratio 3:2). The difference between males and females was not significant (p&gt;0.05). PGC was highly seen in older patients when compared with younger patients (p:000). The average vertical and horizontal dimension of PGC was 2,56±0,98mm and 3,39±1,29 mm respectively. The average total calcified area was 5,45±3,75 mm2. Conclusion: This study did not find any correlation between age, gender, and linear measurements. However, the average calcified are in men was found to be significantly higher than in women.

Astrocyte Dysregulation and Calcium Ion Imbalance May Link the Development of Osteoporosis and Alzheimer’s Disease

The typical symptoms of patients with Alzheimer’s disease (AD) are amyloid-β (Aβ) plaques and tau hyperphosphorylation. However, recent studies show that these symptoms are not the cause of the disease but are generated after the pathogenesis. Compared with other types of dementia, AD has the obvious features of pineal gland calcification and decreased melatonin production. The pineal gland is mainly composed of pinealocytes that release melatonin and astrocytes. Astrocytes function to maintain a balanced concentration of calcium ions, provide nerve cell nutrients, and migrate nutrients in vivo. Calcium ions are among the most important neurotransmitters. Once triggered, a calcium wave can be formed between astrocytes to activate other astrocytes to transmit information. Most calcium is stored in the skeleton. Bone tissue is composed mainly of osteocytes, osteoblasts, and osteoclasts. Of these, osteocyte is a kind of astrocyte which regulates the activity of osteoclasts and osteoblasts. The pineal gland is composed mainly of astrocytes; osteocytes are also a kind of astrocyte. Therefore, we conclude that when astrocytes are gradually disabled, calcium may be lost from the bones, prompting osteoporosis. The calcium ions then released into the blood may accumulate and cause ectopic calcification in the pineal gland, which promotes the occurrence of AD. Finally, this study used aspects of drugs and hormones (bone and calcium metabolism hormones and melatonin) to infer the hypothesis, which proposes that astrocyte dysregulation promotes the long-term imbalance of calcium ions in vivo and leads to osteoporosis and AD.

Running on Empty: Of Hypopinealism and Human Seasonality

The pineal hormone melatonin is the natural transducer of the environmental light-dark signal to the body. Although the responsiveness to photoperiod is well-conserved in humans, only about 25 percent of the human population experiences seasonal changes in behavior. As a consequence, humans seem to have adapted-at least partly-to the seasonal changes in day length. The aim of the study was to demonstrate that the individual melatonin deficit marker DOC (degree of pineal calcification) is related to variation of seasonal phenomena in humans. Out of 3,011 patients in which cranial computer tomography (cCT) was performed for diagnostic reasons, 97 consecutive "healthy" subjects (43 female, 54 male; age 18-68 yrs, mean ± SD: 35.0 ± 13.1) were included. Exclusion criteria were pathological finding in cCT, acute/chronic illness including alcohol/drug abuse, shift work, and medication, which are known to influence melatonin excretion. The degree of pineal calcification (DOC) was semiquantitatively determined using the previously validated method. The Seasonal Pattern Assessment Questionnaire (SPAQ) was performed in a telephone interview. Twenty-six subjects fulfilled the criteria for seasonal affective disorder (SAD) or subsyndromal (S) SAD. Seasonality was more pronounced in women than in men (SPAQ seasonality score: 7.8 ± 4.0 vs. 4.9 ± 4.5; p = 0.001) and negatively and significantly associated with age (r = -0.178; p = 0.04). The subjective sleep length significantly varied between seasons (one-way repeated measures ANOVA: F = 45.75; p < 0.0001), with sleep during winter being 53 min (±70 min) longer than during summer. Controlling for age, the total seasonality score was negatively and significantly associated with DOC (r₉₄ = -0.214; p = 0.036). Data confirm earlier studies with respect to distribution of seasonality with sex and age. The survival of seasonality in the sleep length of people living in an urban environment underlines functionality of the circadian timing system in modern societies. Moreover, data confirm for the first time that diminished experience of seasonality in behavior is associated with a reduced individual capacity to produce melatonin.

Serum Daytime Melatonin Levels Reflect Cerebrospinal Fluid Melatonin Levels in Alzheimer's Disease but Are Not Correlated with Cognitive Decline

Background:

Nocturnal cerebrospinal fluid (CSF) and blood melatonin levels are altered in Alzheimer’s disease (AD). However, literature remains inconclusive on daytime blood melatonin levels. A positive correlation between melatonin levels and Mini-Mental State Examination (MMSE) scores in AD subjects has been evidenced following cross-sectional analyses. Whereas a correlation between serum and spinal CSF melatonin has been shown in healthy volunteers, an equal investigation in AD patients still has to be undertaken.

Objective:

1) To evaluate whether serum melatonin levels correlate with spinal CSF melatonin levels in AD. 2) To compare daytime CSF and serum melatonin levels between patients with AD dementia, mild cognitive impairment due to AD, and healthy controls, and to evaluate whether melatonin can affect cognitive decline in AD.

Methods:

Subjects with AD and healthy controls included in two existing cohorts, of whom a CSF and serum sample was available at the neurobiobank and had at least 6 months of neuropsychological follow-up, were included in the present study. Melatonin concentrations were measured with liquid chromatography-mass spectrometry.

Results:

Daytime serum melatonin levels correlated with spinal CSF melatonin levels in AD (r = 0.751, p < 0.001). No significant differences regarding daytime melatonin levels were found between patients and controls. No correlations were observed between daytime melatonin levels and MMSE score changes.

Conclusion:

Daytime serum melatonin accurately reflects CSF melatonin levels in AD, raising the possibility to assess melatonin alterations by solely performing blood sampling if also confirmed for night-time values. However, daytime melatonin levels are not associated with changes of cognitive impairment.

Mass-spectrometry analysis of the human pineal proteome during night and day and in autism

The human pineal gland regulates day-night dynamics of multiple physiological processes, especially through the secretion of melatonin. Using mass-spectrometry-based proteomics and dedicated analysis tools, we identify proteins in the human pineal gland and analyze systematically their variation throughout the day and compare these changes in the pineal proteome between control specimens and donors diagnosed with autism. Results reveal diverse regulated clusters of proteins with, among others, catabolic carbohydrate process and cytoplasmic membrane-bounded vesicle-related proteins differing between day and night and/or control versus autism pineal glands. These data show novel and unexpected processes happening in the human pineal gland during the day/night rhythm as well as specific differences between autism donor pineal glands and those from controls.

Melatonin levels in the Alzheimer's disease continuum: a systematic review

Background

The search for new Alzheimer’s disease (AD) cerebrospinal fluid (CSF) and blood biomarkers with potential pathophysiological and clinical relevance continues, as new biomarkers might lead to improved early and differential diagnosis, monitoring of disease progression and might even identify new druggable targets. Melatonin might be an interesting biomarker as an inverse correlation between CSF melatonin levels, and severity of the neuropathology as measured by Braak stages has been described. Melatonin can be measured in different body fluids, such as CSF, blood, saliva and urine.

Objectives

The aim of this systematic review was to review all available studies regarding melatonin levels in different body fluids in the AD continuum and give an extensive overview of reported outcomes.

Methods

We included papers comparing melatonin levels between healthy controls and human patients belonging to the AD continuum. A systematic search of PubMed and Web of Science led to inclusion of 20 full-length English papers following exclusion of duplicates.

Results

This systematic literature search showed that disruptions in melatonin levels occur with age, but also in AD when compared to age-matched controls. Night-time melatonin levels were found to be lower in CSF and blood of AD patients as compared to controls. Literature was not conclusive regarding alterations in blood daytime melatonin levels or regarding saliva melatonin in AD patients. Decreased total and night-time melatonin production has been described in urine of AD patients.

Conclusion

Our systematic review shows evidence for disruptions in (night-time) melatonin levels in AD as compared to age-matched controls. Although more studies are needed to understand the contribution of disruption of the melatonergic system to the pathophysiology of AD, the potential anti-AD effects that have been attributed to melatonin, renders research on this topic relevant for the discovery of potential future treatment effects of melatonin for AD. The use of melatonin as potential blood biomarker for disease progression should also be further investigated.

Nature and clinical significance of incidental findings in maxillofacial cone-beam computed tomography: a systematic review

OBJECTIVE

This systematic review was conducted to assess the types, potential clinical significance, and treatment implications of incidental findings (IFs) in CBCT diagnostic imaging of the maxillofacial region.

MATERIAL AND METHODS

The authors searched several electronic databases and grey literature without time restriction for studies on the IFs in maxillofacial CBCT. Studies that classified the IFs based on their potential clinical significance were included. The methodological quality of the included studies was evaluated by the STROBE criteria.

RESULTS

The online searches of the electronic databases yielded 1323 records. Five articles were included in the final qualitative analysis. The methodological quality ranged from low to moderate risk of bias. Percentages of IFs with high (requiring intervention/referral), moderate (requiring monitoring), and low clinical significance ranged from 0.3 to 31.4%, 15.6 to 28.9%, and 43.46 to 71.1%, respectively. There was an inconsistency between the studies in the clinical significance of 58.8% of the IFs identified.

CONCLUSION

Most IFs in maxillofacial CBCT are either normal variants or findings that do not require referral or treatment. There was no clear consensus on the recommended management of most common IFs. The lack of consensus on clinical significance emphasizes the importance of collaboration between medical and dental specialties to establish professional guidelines for the management of commonly encountered IFs in CBCT.

Relationship of the content of vitamin D and melatonin in blood serum and pineal gland calcifications in patients with malignant bone tumors

The aim of the study was to investigate the relationship between the vitamin D content, melatonin and the characteristics of pineal gland calcifications in patients with malignant tumors of the bones of the lower extremities. Vitamin D deficiency and pineal gland calcifications are observed in almost 100 % of patients with malignant tumors of the lower extremities’ bones. The high heterogeneity of calcifications and its dynamics during the treatment of patients may indicate the processes of their litholysis and dissolution.

Thymus-Pineal Gland Axis: Revisiting Its Role in Human Life and Ageing

For years the thymus gland (TG) and the pineal gland (PG) have been subject of increasingly in-depth studies, but only recently a link that can associate the activities of the two organs has been identified. Considering, on the one hand, the well-known immune activity of thymus and, on the other, the increasingly emerging immunological roles of circadian oscillators and the rhythmically secreted main pineal product, melatonin, many studies aimed to analyse the possible existence of an interaction between these two systems. Moreover, data confirmed that the immune system is functionally associated with the nervous and endocrine systems determining an integrated dynamic network. In addition, recent researches showed a similar, characteristic involution process both in TG and PG. Since the second half of the 20th century, evidence led to the definition of an effectively interacting thymus-pineal axis (TG-PG axis), but much has to be done. In this sense, the aim of this review is to summarize what is actually known about this topic, focusing on the impact of the TG-PG axis on human life and ageing. We would like to give more emphasis to the implications of this dynamical interaction in a possible therapeutic strategy for human health. Moreover, we focused on all the products of TG and PG in order to collect what is known about the role of peptides other than melatonin. The results available today are often unclear and not linear. These peptides have not been well studied and defined over the years. In this review we hope to awake the interest of the scientific community in them and in their future pharmacological applications.

Pineal volume reduction in patients with mild cognitive impairment who converted to Alzheimer's disease

AIM

Pineal parenchymal volume (PPV) reduction is one of the predisposing factors for Alzheimer's disease (AD). Therefore, PPV could be used as a predictor of developing AD in clinical settings. We investigated whether PPV in patients with mild cognitive impairment (MCI) was correlated with conversion of these patients to AD.

METHODS

A total of 237 patients with MCI underwent brain magnetic resonance imaging. A two-sample t-test was used to compare PPV at baseline in MCI patients who converted to AD (MCI-C) with those who did not convert (MCI-NC). Logistic regression analysis with forced entry was used to identify predictors of AD, with variables of PPV, age, sex, education, APOE-ε4 alleles, Mini Mental State Examination score, and total intracranial volume at baseline. Two-way repeated-measures analysis of variance was conducted to compare PPV at baseline and at the last examination in the MCI-C and MCI-NC groups.

RESULTS

PPV in the MCI-C group was significantly lower than that in the MCI-NC group. In logistic regression analysis, two independent predictors of AD were identified: Mini Mental State Examination and PPV. Two-way repeated-measures analysis of variance revealed a significant group effect, but no time effect.

CONCLUSION

The pineal volume is a predictor of AD conversion, and pineal volume reduction in AD starts early when patients are still in the MCI stage. Thus, pineal volume reduction might be useful as a predictor of developing AD in clinical settings.

Fluoride-Free Diet Stimulates Pineal Growth in Aged Male Rats

The pineal gland is a naturally calcifying endocrine organ which secretes the sleep-promoting hormone melatonin. Age-related changes of the pineal have been observed, including decreased pinealocyte numbers, increased calcification, and a reduction in melatonin production. Since fluoride is attracted to calcium within the pineal gland, this study sought to examine the effects of a fluoride-free diet on the morphology of the pineal gland of aged male rats (26 months old). All animals had previously been raised on standard fluoridated food and drinking water. These control animals were compared to other animals that were placed on a fluoride-free diet ("fluoride flush") for 4 or 8 weeks. At 4 weeks, pineal glands from fluoride-free animals showed a 96% increase in supporting cell numbers and at 8 weeks a 73% increase in the number of pinealocytes compared to control animals. In contrast, the number of pinealocytes and supporting cells in animals given an initial 4-week fluoride flush followed by a return to fluoridated drinking water (1.2 ppm NaF) for 4 weeks were not different from control animals. Our findings therefore demonstrate that a fluoride-free diet encouraged pinealocyte proliferation and pineal gland growth in aged animals and fluoride treatment inhibited gland growth. These findings suggest that dietary fluoride may be detrimental to the pineal gland.

Therapeutic potential of neurogenesis and melatonin regulation in Alzheimer's disease

Alzheimer's disease (AD) is an age-related neurodegenerative disorder characterized by the hallmark pathologies of amyloid-beta plaques and neurofibrillary tangles. Symptoms of this devastating disease include behavioral changes and deterioration of higher cognitive functions. Impairment of neurogenesis has also been shown to occur in AD, which adversely impacts new neuronal cell growth, differentiation, and survival. This impairment possibly results from the cumulative effects of the various pathologies of AD. Preclinical studies have suggested that the administration of melatonin-the pineal hormone primarily responsible for the regulation of the circadian rhythm-targets the effects of AD pathologies and improves cognitive impairment. It is postulated that by mitigating the effect of these pathologies, melatonin can also rescue neurogenesis impairment. This review aims to explore the effect of AD pathologies on neurogenesis, as well as the mechanisms by which melatonin is able to ameliorate AD pathologies to potentially promote neurogenesis.

SWI and phase imaging reveal intracranial calcifications in the P301L mouse model of human tauopathy

Objective

Brain calcifications are associated with several neurodegenerative diseases. Here, we describe the occurrence of intracranial calcifications as a new phenotype in transgenic P301L mice overexpressing four repeat tau, a model of human tauopathy.

Materials and methods

Thirty-six P301L mice (Thy1.2) and ten age-matched non-transgenic littermates of different ages were assessed. Gradient echo data were acquired in vivo and ex vivo at 7 T and 9.4 T for susceptibility-weighted imaging (SWI) and phase imaging. In addition, ex vivo micro-computed tomography (μCT) was performed. Histochemistry and immunohistochemistry were used to investigate the nature of the imaging lesions.

Results

SW images revealed regional hypointensities in the hippocampus, cortex, caudate nucleus, and thalamus of P301L mice, which in corresponding phase images indicated diamagnetic lesions. Concomitantly, µCT detected hyperdense lesions, though fewer lesions were observed compared to MRI. Diamagnetic susceptibility lesions in the hippocampus increased with age. The immunochemical staining of brain sections revealed osteocalcin-positive deposits. Furthermore, intra-neuronal and vessel-associated osteocalcin-containing nodules co-localized with phosphorylated-tau (AT8 and AT100) in the hippocampus, while vascular osteocalcin-containing nodules were detected in the thalamus in the absence of phosphorylated-tau deposition.

Discussion

SWI and phase imaging sensitively detected intracranial calcifications in the P301L mouse model of human tauopathy.

Electronic supplementary material

The online version of this article (10.1007/s10334-020-00855-3) contains supplementary material, which is available to authorized users.

Fluoride and Pineal Gland

The pineal gland is an endocrine gland whose main function is the biosynthesis and secretion of melatonin, a hormone responsible for regulating circadian rhythms, e.g., the sleep/wake cycle. Due to its exceptionally high vascularization and its location outside the blood–brain barrier, the pineal gland may accumulate significant amounts of calcium and fluoride, making it the most fluoride-saturated organ of the human body. Both the calcification and accumulation of fluoride may result in melatonin deficiency.

Melatonin affects the release of exosomes and tau-content in in vitro amyloid-beta toxicity model

BACKGROUND

Recent studies have been revealed that oxidative damage is the main cause of aging and age-related neurodegenerative diseases like Alzheimer's disease (AD). Melatonin is secreted from the pineal gland and its secretion has been found to be altered in AD. In the last decade the role of exosomes in spreading toxic proteins and inducing the propagation of diseases like AD has been discussed. However, it is not known how melatonin affects the amount of exosomes released from the cells and the content of the exosomes.

OBJECTIVE

Herein, we investigated the possible role of melatonin treatment in the releasing of exosomes and exosomal tau content in an in vitro Aβ toxicity model.

METHOD

SH-SY5Y cell line was used. The optimum concentration of Aβ was determined by cell viability and cell proliferation tests. Melatonin (100 µM) was applied before and after Aβ application. Total exosomes isolated from cell culture media were immunoprecipitated. The amount of released exosomes and their tau content were analyzed by Western blots.

RESULTS

Our data demonstrated for the first time that melatonin treatment clearly affected the amount of released exosomes. It would decrease the amyloid beta load and toxicity by inhibiting exosome release. We also demonstated that melatonin also affected the level of tau carried by exosomes depending on whether melatonin was applied before or after Aβ application.

CONCLUSION

It is considered that the effect of melatonin in the release of exosomes and exosomal tau content would contribute the development of therapeutic strategies in AD and related disorders.

Transcriptome Analysis of Pineal Glands in the Mouse Model of Alzheimer's Disease

The pineal gland maintains the circadian rhythm in the body by secreting the hormone melatonin. Alzheimer's disease (AD) is the most common neurodegenerative disease. Pineal gland impairment in AD is widely observed, but no study to date has analyzed the transcriptome in the pineal glands of AD. To establish resources for the study on pineal gland dysfunction in AD, we performed a transcriptome analysis of the pineal glands of AD model mice and compared them to those of wild type mice. We identified the global change of diverse protein-coding RNAs, which are implicated in the alteration in cellular transport, protein transport, protein folding, collagen expression, histone dosage, and the electron transfer system. We also discovered various dysregulated long noncoding RNAs and circular RNAs in the pineal glands of mice with AD. This study showed that the expression of diverse RNAs with important functional implications in AD was changed in the pineal gland of the AD mouse model. The analyzed data reported in this study will be an important resource for future studies to elucidate the altered physiology of the pineal gland in AD.

Pineal gland dysfunction in Alzheimer's disease: relationship with the immune-pineal axis, sleep disturbance, and neurogenesis

Alzheimer’s disease (AD) is a globally common neurodegenerative disease, which is accompanied by alterations to various lifestyle patterns, such as sleep disturbance. The pineal gland is the primary endocrine organ that secretes hormones, such as melatonin, and controls the circadian rhythms. The decrease in pineal gland volume and pineal calcification leads to the reduction of melatonin production. Melatonin has been reported to have multiple roles in the central nervous system (CNS), including improving neurogenesis and synaptic plasticity, suppressing neuroinflammation, enhancing memory function, and protecting against oxidative stress. Recently, reduced pineal gland volume and pineal calcification, accompanied by cognitive decline and sleep disturbances have been observed in AD patients. Here, I review current significant evidence of the contribution of pineal dysfunction in AD to the progress of AD neuropathology. I suggest new insights to understanding the relationship between AD pathogenesis and pineal gland function.

Melatonin in Synaptic Impairments of Alzheimer's Disease

Alzheimer's disease (AD) underlies dementia for millions of people worldwide with no effective treatment. The dementia of AD is thought stem from the impairments of the synapses because of their critical roles in cognition. Melatonin is a neurohormone mainly released by the pineal gland in a circadian manner and it regulates brain functions in various manners. It is reported that both the melatonin deficit and synaptic impairments are present in the very early stage of AD and strongly contribute to the progress of AD. In the mammalian brains, the effects of melatonin are mainly relayed by two of its receptors, melatonin receptor type 1a (MT1) and 1b (MT2). To have a clear idea on the roles of melatonin in synaptic impairments of AD, this review discussed the actions of melatonin and its receptors in the stabilization of synapses, modulation of long-term potentiation, as well as their contributions in the transmissions of glutamatergic, GABAergic and dopaminergic synapses, which are the three main types of synapses relevant to the synaptic strength. The synaptic protective roles of melatonin in AD treatment were also summarized. Regarding its protective roles against amyloid-β neurotoxicity, tau hyperphosphorylation, oxygenation, inflammation as well as synaptic dysfunctions, melatonin may be an ideal therapeutic agent against AD at early stage.

Role of immune-pineal axis in neurodegenerative diseases, unraveling novel hybrid dark hormone therapies

The anti-oxidant effects of melatonin and the immune-pineal axis are well established. However, how they play a role in the pathogenesis of neurodegenerative diseases is not well elucidated. A better understanding of this neuro-immuno-endocrinological link can help in the development of novel therapies with higher efficacy to alleviate symptomatology, slow disease progression and improve the quality of life. Recent studies have shown that the immune-pineal axis acts as an immunological buffer, neurohormonal switch and it also intricately links the pathogenesis of neurodegenerative diseases (like Multiple sclerosis, Alzheimer's disease, Parkinson's disease) and inflammation at a molecular level. Furthermore, alteration in circadian melatonin production is seen in neurodegenerative diseases. This review will summarise the mechanics by which the immune-pineal axis and neuro-immuno-endocrinological disturbances affect the pathogenesis and progression of neurodegenerative diseases. It will also explore, how this understanding will help in the development of novel hybrid melatonin hormone therapies for the treatment of neurodegenerative diseases.

Pineal Calcification, Melatonin Production, Aging, Associated Health Consequences and Rejuvenation of the Pineal Gland

The pineal gland is a unique organ that synthesizes melatonin as the signaling molecule of natural photoperiodic environment and as a potent neuronal protective antioxidant. An intact and functional pineal gland is necessary for preserving optimal human health. Unfortunately, this gland has the highest calcification rate among all organs and tissues of the human body. Pineal calcification jeopardizes melatonin's synthetic capacity and is associated with a variety of neuronal diseases. In the current review, we summarized the potential mechanisms of how this process may occur under pathological conditions or during aging. We hypothesized that pineal calcification is an active process and resembles in some respects of bone formation. The mesenchymal stem cells and melatonin participate in this process. Finally, we suggest that preservation of pineal health can be achieved by retarding its premature calcification or even rejuvenating the calcified gland.

Night-time activity forecast by season and weather in a longitudinal design - natural light effects on three years' rest-activity cycles in nursing home residents with dementia

Backround: Night-time agitation is a frequent symptom of dementia. It often causes nursing home admission and has been linked to circadian rhythm disturbances. A positive influence of light interventions on night-time agitation was shown in several studies. The aim of our study was to investigate whether there is a long-term association between regional weather data (as indicator for daylight availability) and 24-hour variations of motor activity.

METHODS

Motor activity of 20 elderly nursing home residents living with dementia was analyzed using recordings of continuously worn wrist activity monitors over a three-year period. The average recording duration was 479 ± 206 days per participant (mean ± SD). Regional cloud amount and day length data from the local weather station (latitude: 52°56'N) were included in the analysis to investigate their effects on several activity variables.

RESULTS

Nocturnal rest, here defined as the five consecutive hours with the least motor activity during 24 hours (L5), was the most predictable activity variable per participant. There was a significant interaction of night-time activity with day length and cloud amount (F 1,1174 = 4.39; p = 0.036). Night-time activity was higher on cloudy short days than on clear short days (p = 0.007), and it was also higher on cloudy short days than on cloudy long days (p = 0.032).

CONCLUSIONS

The need for sufficient zeitgeber (time cue) strength during winter time, especially when days are short and skies are cloudy, is crucial for elderly people living with dementia. Activity forecast by season and weather might be a valuable approach to anticipate adequately complementary use of electrical light and thereby foster lower night-time activity.

Prevalence of pineal gland calcification as an incidental finding in patients referred for implant dental therapy

PURPOSE

Pineal gland calcification has been proposed to play a role in the pathogenesis of Alzheimer disease. This study evaluated the prevalence and extent of pineal gland calcification in cone-beam computed tomography (CBCT) scans of patients referred for dental implant therapy who could possibly be a vulnerable group for this condition.

MATERIALS AND METHODS

A retrospective evaluation of 500 CBCT scans was conducted. Scans that showed the area where the pineal gland was located were included. The scans were initially screened by a single observer to record the prevalence and extent of calcification. Six weeks following the completion of the study, another investigator randomly reviewed and selected 50 scans to investigate inter-observer variation, which was evaluated using reliability analysis statistics. The prevalence and measurements of the calcifications were reported using descriptive statistics. The chi-square test was used to compare the prevalence between males and females.

RESULTS

The prevalence of pineal gland calcification was 58.8%. There was no statistically significant correlation between age and the extent of the calcification. The prevalence of calcification was 58.6% in females and 59.0% in males. The average anteroposterior measurement was 3.73±1.63 mm, while the average mediolateral measurement was 3.47±1.31 mm. The average total calcified area was 9.79±7.59 mm².

CONCLUSION

The prevalence of pineal gland calcification was high in patients undergoing implant therapy. While not all pineal gland calcifications lead to neurodegenerative disorders, they should be strongly considered in the presence of any symptoms as a reason to initiate further investigations.

Melatonin for Sleep Disorders in Patients with Neurodegenerative Diseases

In patients with neurodegenerative diseases, sleep disorders are common; they impair the quality of life for patients and caregivers and are associated with poorer clinical outcomes. Melatonin has circadian, hypnotic, and free radical-scavenging effects, and preclinical data suggest benefits of melatonin on neurodegeneration. However, randomized, controlled trials of melatonin in patients with neurodegenerative diseases have not shown strong effects. Trials in Alzheimer's patients demonstrate a lack of benefit on sleep quantity. Subjective measures of sleep quality are mixed, with possible symptomatic improvements seen only on some measures or at some time points. Benefits on cognition have not been observed across several studies. In Parkinson's patients, there may be minimal benefit on objective sleep measures, but a suggestion of subjective benefit in few, small studies. Effective treatments for the sleep disorders associated with neurodegenerative diseases are urgently needed, but current data are insufficient to establish melatonin as such a treatment.

Characterization of human pineal gland proteome

The pineal gland is a neuroendocrine gland located at the center of the brain. It is known to regulate various physiological functions in the body through secretion of the neurohormone melatonin. Comprehensive characterization of the human pineal gland proteome has not been undertaken to date. We employed a high-resolution mass spectrometry-based approach to characterize the proteome of the human pineal gland. A total of 5874 proteins were identified from the human pineal gland in this study. Of these, 5820 proteins were identified from the human pineal gland for the first time. Interestingly, 1136 proteins from the human pineal gland were found to contain a signal peptide domain, which indicates the secretory nature of these proteins. An unbiased global proteomic profile of this biomedically important organ should benefit molecular research to unravel the role of the pineal gland in neuropsychiatric and neurodegenerative diseases.

Texture analyses of quantitative susceptibility maps to differentiate Alzheimer's disease from cognitive normal and mild cognitive impairment

PURPOSE

Although a number of studies have focused on finding anatomical regions in which iron concentrations are high, no study has been conducted to examine the overall variations in susceptibility maps of Alzheimer's disease (AD). The objective of this study, therefore, was to differentiate AD from cognitive normal (CN) and mild cognitive impairment (MCI) using a texture analysis of quantitative susceptibility maps (QSMs).

METHODS

The study was approved by the local institutional review board, and informed consent was obtained from all subjects. In each participant group-CN, MCI, and AD-18 elderly subjects were enrolled. A fully first-order flow-compensated 3D gradient-echo sequence was run to obtain axial magnitudes and phase images and to produce QSM data. Sagittal structural 3D T1-weighted (3DT1W) images were also obtained with the magnetization-prepared rapid acquisition of gradient-echo sequence to obtain brain tissue images. The first- and second-order texture parameters of the QSMs and 3DT1W images were obtained to evaluate group differences using a one-way analysis of covariance.

RESULTS

For the first-order QSM analysis, mean, standard deviation, and covariance of signal intensity separated the subject groups (F = 5.191, p = 0.009). For the second-order analysis, angular second moment, contrast, and correlation separated the subject groups (F = 6.896, p = 0.002). Finally, a receiver operating characteristic curve analysis differentiated MCI from CN in white matter on the QSMs (z = 3.092, p = 0.0020).

CONCLUSIONS

This was the first study to evaluate the textures of QSM in AD, which overcame the limitations of voxel-based analyses. The QSM texture analysis successfully distinguished both AD and MCI from CN and outperformed the voxel-based analysis using 3DT1-weighed images in separating MCI from CN. The first-order textures were more efficient in differentiating MCI from CN than did the second-order.

Diagnostic accuracy of susceptibility-weighted magnetic resonance imaging for the evaluation of pineal gland calcification

Objectives

To determine the diagnostic performance of susceptibility-weighted magnetic resonance imaging (SWMR) for the detection of pineal gland calcifications (PGC) compared to conventional magnetic resonance imaging (MRI) sequences, using computed tomography (CT) as a reference standard.

Methods

384 patients who received a 1.5 Tesla MRI scan including SWMR sequences and a CT scan of the brain between January 2014 and October 2016 were retrospectively evaluated. 346 patients were included in the analysis, of which 214 showed PGC on CT scans. To assess correlation between imaging modalities, the maximum calcification diameter was used. Sensitivity and specificity and intra- and interobserver reliability were calculated for SWMR and conventional MRI sequences.

Results

SWMR reached a sensitivity of 95% (95% CI: 91%-97%) and a specificity of 96% (95% CI: 91%-99%) for the detection of PGC, whereas conventional MRI achieved a sensitivity of 43% (95% CI: 36%-50%) and a specificity of 96% (95% CI: 91%-99%). Detection rates for calcifications in SWMR and conventional MRI differed significantly (95% versus 43%, p<0.001). Diameter measurements between SWMR and CT showed a close correlation (R² = 0.85, p<0.001) with a slight but not significant overestimation of size (SWMR: 6.5 mm ± 2.5; CT: 5.9 mm ± 2.4, p = 0.02). Interobserver-agreement for diameter measurements was excellent on SWMR (ICC = 0.984, p < 0.0001).

Conclusions

Combining SWMR magnitude and phase information enables the accurate detection of PGC and offers a better diagnostic performance than conventional MRI with CT as a reference standard.

Melatonin Alleviates the Epilepsy-Associated Impairments in Hippocampal LTP and Spatial Learning Through Rescue of Surface GluR2 Expression at Hippocampal CA1 Synapses

Epilepsy-associated cognitive impairment is common, and negatively impacts patients' quality of life. However, most antiepileptic drugs focus on the suppression of seizures, and fewer emphasize treatment of cognitive dysfunction. Melatonin, an indolamine synthesized primarily in the pineal grand, is reported to be neuroprotective against several central nervous system disorders. In this study, we investigated whether melatonin could reverse cognitive dysfunction in lithium-pilocarpine treated rats. Chronic treatment with melatonin (8 mg/kg daily for 15 days) after induction of status epilepticus significantly alleviated seizure severity, reduced neuronal death in the CA1 region of the hippocampus, improved spatial learning (as measured by the Morris water maze test), and reversed LTP impairments, compared to vehicle treatment. Furthermore, we found that melatonin rescued the decreased surface levels of GluR2 in the CA1 region observed in epilepsy, which might be the underlying mechanism of the neuroprotective and synapse-modulating function of melatonin. Our study provides experimental evidence for the possible clinical utility of melatonin as an adjunctive therapy to prevent epilepsy-associated cognitive impairments.

Insomnia and dementia: is agomelatine treatment helpful? Case report and review of the literature

The treatment of sleep disorders in Alzheimer's disease (AD) may be quite challenging in elderly patients because of drug side effects or interactions and comorbid local or systemic diseases. Here, we report a patient with AD, who was suffering from severe insomnia and depression. We ordered agomelatine for the treatment of insomnia in this patient, and it was quite helpful not only for insomnia but also for depression and for the cognitive symptoms related with dementia. Our aim was to share these observations for similar patients.

Pineal calcification is associated with pediatric primary brain tumor

AIM

Melatonin has been associated with various tumors, including brain tumor, and shown to inhibit growth of neuroblastoma cells and gliomas in animal models. Likewise, patients with glioblastoma receiving melatonin reported better survival than controls. Pineal calcification may lead to a decreased production of melatonin by calcified glands. This study assessed association between pineal calcification and primary brain tumor in pediatric/adolescent patients.

METHODS

Medical chart review was conducted in 181 patients <15 years old who had undergone brain computed tomography (CT) during 2008-2012. Pineal calcification was identified using brain CT scan by an experienced neurosurgeon. Primary brain tumor was confirmed by CT scan and histology, and association with pineal calcification was estimated using multiple logistic regression, adjusted for age and gender.

RESULTS

Primary brain tumor was detected in 51 patients (mean age 9.0, standard deviation 4.0 years), with medulloblastoma being the most common (11 patients). Pineal calcification was detected in 12 patients (23.5%) with primary brain tumor, while only 11 patients (8.5%) without tumor had pineal calcification. Adjusted for patients' ages and genders, pineal calcification was associated with an increase in primary brain tumor of 2.82-fold (odds ratio 2.82; 95% confidence interval 1.12-7.08, P = 0.027).

CONCLUSION

Pineal calcification appears to be associated with primary brain tumor. Further studies to explore this link are discussed and warranted.

Pineal Gland Calcification in Kurdistan: A Cross-Sectional Study of 480 Roentgenograms

Objective

The goal of this study was to compare the incidence of Pineal Gland Calcification (PGC) by age group and gender among the populations living in the Kurdistan Region-Iraq.

Methods

This prospective study examined skull X-rays of 480 patients between the ages of 3 and 89 years who sought care at a large teaching public hospital in Duhok, Iraq from June 2014 to November 2014. Descriptive statistics and a binary logistic regression were used for analysis.

Results

The overall incidence rate of PGC among the study population was 26.9% with the 51–60 age group and males having the highest incidence. PGC incidence increased after the first decade and remained steady until the age of 60. Thereafter the incidence began to decrease. Logistic regression analysis revealed that both age and gender significantly affected the risk of PGC. After adjusting for age, males were 1.94 (95% CI, 1.26–2.99) times more likely to have PGC compared to females. In addition, a one year increase in age increases the odds of developing PGC by 1.02 (95% CI, 1.01–1.03) units after controlling for the effects of gender.

Conclusion

Our analysis demonstrated a close relationship between PGC and age and gender, supporting a link between the development of PGC and these factors. This study provides a basis for future researchers to further investigate the nature and mechanisms underlying pineal gland calcification.

Assessment of Pineal Gland Volume and Calcification in Healthy Subjects: Is it Related to Aging?

Purpose:

The human pineal gland is a small neuroendocrine organ which produces melatonin. The main goal of this study was to provide a reference range for pineal volume in all age groups and to determine calcified and noncalcified tissue and their proportions, which may be a reflection of melatonin production in all age groups, by using very thin computerized tomography (CT) slices.

Materials and methods:

A total of 167 outpatients had undergone cranial CT. Each of the subject’s total pineal volume (TPV), calcified pineal volume (CPV) and noncalcified pineal volume (NPV) according to age groups were calculated in cubic millimeters. Also, proportion of calcification (POC) was noted.

Results:

The median values were 88.5 mm³ (12.3 mm³–411mm³) for TPV, 74.3 mm³ (12.3 mm³–298 mm³) for NPV, and 3.9 mm³ (0 mm³–141 mm³) for CPV. POC showed a gradual increase from 0–49 years. In the ≥70 group, when compared with the 60–69 age group, CPV and POC values were significantly lower (P: 0.036, P: 0.034, respectively).

Conclusion:

This study brings a radiological point of view to the distribution of pineal calcification according to age that has a link with melatonin secretion.

Sleep disturbances and dementia

Sleep is a complex behavioural state, the ultimate functions of which remain poorly understood. It becomes more fragmented as we age, with more night-time awakenings and greater tendency for daytime sleep. The magnitude of disordered sleep among individuals affected by dementia has been clearly demonstrated, and disturbed sleep is a major clinical problem in dementia. Comorbid insomnia and other sleep disturbances are common in patients with neurodegenerative disorders, such Alzheimer's disease and other dementing disorders. How and when sleep problems manifest themselves can depend on the type of dementia involved as well as the stage of the dementia. However, differences in sleep pattern presentation show more variation during the initial stages of dementias than they do during the later stages. Effective, pragmatic interventions are largely anecdotal and untested.

Stroke and pineal gland calcification: lack of association. Results from a population-based study (The Atahualpa Project)

OBJECTIVE

It has been suggested that pineal gland calcifications (PGC) represent a risk factor for stroke; however, information comes from a single retrospective hospital-based registry. We aimed to validate this association in a population-based study conducted in rural Ecuador.

METHODS

Atahualpa residents aged ≥60 years were identified during a door-to-door survey and invited to undergo neuroimaging studies (CT/MRI) for identification and rating PGC and lesions consistent with cerebral infarcts and hemorrhages. Cardiovascular health (CVH) status was assessed according to the American Heart Association criteria, and clinical strokes were identified by the use of a validated field instrument and confirmed by neurologists.

RESULTS

Out of 248 participants (mean age 70±8 years, 59% women, 73% with poor CVH), 137 (55%) had PGC and 39 (16%) had strokes (silent in 28 cases). PGC were noted in 61% versus 54% persons with and without stroke, respectively. After adjusting for age, sex and cardiovascular health, logistic and ordinal logistic regression models showed no association between any evidence (p=0.916) or severity (p=0.740) of PGC and stroke.

CONCLUSION

PGC is not associated with stroke in this population of community-dwelling elders, where prevalence of PGC and stroke are similar to those found in other regions.

Diminished brain resilience syndrome: A modern day neurological pathology of increased susceptibility to mild brain trauma, concussion, and downstream neurodegeneration

The number of sports-related concussions has been steadily rising in recent years. Diminished brain resilience syndrome is a term coined by the lead author to describe a particular physiological state of nutrient functional deficiency and disrupted homeostatic mechanisms leading to increased susceptibility to previously considered innocuous concussion. We discuss how modern day environmental toxicant exposure, along with major changes in our food supply and lifestyle practices, profoundly reduce the bioavailability of neuro-critical nutrients such that the normal processes of homeostatic balance and resilience are no longer functional. Their diminished capacity triggers physiological and biochemical 'work around' processes that result in undesirable downstream consequences. Exposure to certain environmental chemicals, particularly glyphosate, the active ingredient in the herbicide, Roundup(®), may disrupt the body's innate switching mechanism, which normally turns off the immune response to brain injury once danger has been removed. Deficiencies in serotonin, due to disruption of the shikimate pathway, may lead to impaired melatonin supply, which reduces the resiliency of the brain through reduced antioxidant capacity and alterations in the cerebrospinal fluid, reducing critical protective buffering mechanisms in impact trauma. Depletion of certain rare minerals, overuse of sunscreen and/or overprotection from sun exposure, as well as overindulgence in heavily processed, nutrient deficient foods, further compromise the brain's resilience. Modifications to lifestyle practices, if widely implemented, could significantly reduce this trend of neurological damage.

Prevalence of brain calcifications in a Brazilian cohort: A retrospective study in radiology services

Brain calcifications may be present in a wide range of neuropsychiatric, infectious traumatic, neoplastic and endocrine conditions, associated with motor and cognitive symptoms. They are often considered "physiologic" or pathologic.

OBJECTIVE

To determine the prevalence of brain calcifications in a Brazilian cohort.

METHODS

1898 consecutive patients underwent skull CTs, comprising 836 men and 1062 women.

RESULTS

Among all 1898 patients, 333 (197 women and 136 men) presented with brain calcifications, representing an overall prevalence of 17.54%. The prevalence in the female group was 18.54% versus 16.26% in the male group.

CONCLUSIONS

A growth in incidental findings on CT scans are likely as these exams become more widely available. However, a current debate between radiologists and regulators is set to redefine the CT usage, especially in the United States and the United Kingdom, considering new norms for use and radiation dosage per exam.

Out of the lab and into the bathroom: evening short-term exposure to conventional light suppresses melatonin and increases alertness perception

Life in 24-h society relies on the use of artificial light at night that might disrupt synchronization of the endogenous circadian timing system to the solar day. This could have a negative impact on sleep-wake patterns and psychiatric symptoms. The aim of the study was to investigate the influence of evening light emitted by domestic and work place lamps in a naturalistic setting on melatonin levels and alertness in humans. Healthy subjects (6 male, 3 female, 22-33 years) were exposed to constant dim light (<10 lx) for six evenings from 7:00 p.m. to midnight. On evenings 2 through 6, 1 h before habitual bedtime, they were also exposed to light emitted by 5 different conventional lamps for 30 min. Exposure to yellow light did not alter the increase of melatonin in saliva compared to dim light baseline during (38 ± 27 pg/mL vs. 39 ± 23 pg/mL) and after light exposure (39 ± 22 pg/mL vs. 44 ± 26 pg/mL). In contrast, lighting conditions including blue components reduced melatonin increase significantly both during (office daylight white: 25 ± 16 pg/mL, bathroom daylight white: 24 ± 10 pg/mL, Planon warm white: 26 ± 14 pg/mL, hall daylight white: 22 ± 14 pg/mL) and after light exposure (office daylight white: 25 ± 15 pg/mL, bathroom daylight white: 23 ± 9 pg/mL, Planon warm white: 24 ± 13 pg/mL, hall daylight white: 22 ± 26 pg/mL). Subjective alertness was significantly increased after exposure to three of the lighting conditions which included blue spectral components in their spectra. Evening exposure to conventional lamps in an everyday setting influences melatonin excretion and alertness perception within 30 min.