Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Neurological Entity?

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a disorder of unknown physiopathology with multisystemic repercussions, framed in ICD-11 under the heading of neurology (8E49). There is no specific test to support its clinical diagnosis. Our objective is to review the evidence in neuroimaging and dysautonomia evaluation in order to support the neurological involvement and to find biomarkers serving to identify and/or monitor the pathology. The symptoms typically appear acutely, although they can develop progressively over years; an essential trait for diagnosis is "central" fatigue together with physical and/or mental exhaustion after a small effort. Neuroimaging reveals various morphological, connectivity, metabolic, and functional alterations of low specificity, which can serve to complement the neurological study of the patient. The COMPASS-31 questionnaire is a useful tool to triage patients under suspect of dysautonomia, at which point they may be redirected for deeper evaluation. Recently, alterations in heart rate variability, the Valsalva maneuver, and the tilt table test, together with the presence of serum autoantibodies against adrenergic, cholinergic, and serotonin receptors were shown in a subgroup of patients. This approach provides a way to identify patient phenotypes. Broader studies are needed to establish the level of sensitivity and specificity necessary for their validation. Neuroimaging contributes scarcely to the diagnosis, and this depends on the identification of specific changes. On the other hand, dysautonomia studies, carried out in specialized units, are highly promising in order to support the diagnosis and to identify potential biomarkers. ME/CFS orients towards a functional pathology that mainly involves the autonomic nervous system, although not exclusively.

Effects of Cycloleucine in the Nucleus Accumbens Septi on the Elevated plus Maze Test in Rats.

INTRODUCTION: In recent years, an important number of studies have emphasized the psychopharmacological actions of cycloleucine (1-aminocyclopentanecarboxylic acid) acting on the NR1 subunit (glycine allosteric site) of NMDA (N-methyl-D-aspartic acid) receptor. We studied the effects of its injection in an anxiety test. METHODS: The elevated plus maze test was used. Male rats bilaterally cannulated into the nucleus accumbens septi (NAS) were employed. Rats were divided into 5 groups that received either 1 µL injections of saline or cycloleucine (0.5, 1, 2, or 4 µg) 15 min before testing. RESULTS: Time spent in the open arm was significantly increased by cycloleucine treatment with all doses (1 and 2 µg, p < 0.05; 0.5 and 4 µg, p < 0.01), like number of extreme arrivals (0.5 and 1 µg, p < 0.05; 2 µg, p < 0.01; and 4 µg, p < 0.001). Open arm entries were increased by the highest dose only (4 µg, p < 0.01). DISCUSSION/CONCLUSION: Present results show no difference between all doses in the time spent in the open arm, suggesting an indirect, noncompetitive action of the drug. The increase in extreme arrivals and open arm entries suggests a dose influence in these parameters. We conclude that cycloleucine influence on the NMDA receptors within NAS leads to anxiolytic-like effects and behavioral disinhibition, which once more confirms the involvement of NAS in anxiety processing.

Analysis of the Increase in Bone Mineral Density After Surgical Treatment of Primary Hyperparathyroidism.

AIM: To analyze the effect of the surgery in bone mineral density (BMD) and to study the value of preoperative clinical and analytical factors as predictors of bone increase. MATERIAL AND METHODS: Prospective observational study. Postmenopausal women who were operated for primary hyperparathyroidism were included. A bone densitometry of the lumbar spine and femoral neck and analytical determinations (parathyroid hormone [PTH], alkaline phosphatase, albumin, phosphate, creatinine, 25-hydroxy-vitamin D3, creatinine clearance, and calciuria) were performed previous to the intervention and after 12 months from surgery. RESULTS: Two hundred and twenty-eight patients were operated on for primary hyperparathyroidism were considered for study, 108 postmenopausal women entered in the final analysis. The mean age was 63 ± 7 yr. After the intervention, a significant increase in BMD was observed in the two locations analyzed, although this increase was significant greater at the level of the lumbar spine. In the lumbar spine, 68 patients (63%) recorded a significant postoperative increase in bone density. Median postoperative BMD was 0.860 g/cm2 (interquartile range: 0.93). The observed average percentage of density increase was 6.63 ± 17.9. In femoral neck, 61 patients (56.6%) registered a significant increase in bone density. Median postoperative BMD value was 0.741 g/cm2 (interquartile range: 0.76). The average percentage of density increase was 3.19 ± 17.9. In the lumbar spine, patients with osteoporosis before surgery increased postoperative BMD more frequently than those with osteopenia or normal density. Patients who increased BMD preoperatively presented lower bone density levels both in the lumbar spine (median: 0.775, interquartile range: 0.882) and in the hip (median: 0.655, interquartile range: 0.562) than patients in whom it was not observed postoperative increase. PTH preoperative serum was lower among patients who increased bone density in the femur (median: 141 pg/ml, interquartile range: 291) than among those who did not (median: 152 pg/ml, interquartile range: 342) (p = 0.01). In the multivariate analysis, the increase in BMD in the lumbar spine was related to preoperative BMD (odds ratio [OR] 0.084, 95% confidence interval [CI]: 0.007-0.961); in femoral neck it was related to preoperative BMD (OR 0.001; 95% CI: 0.0-0.028) and to the preoperative PTH serum concentration (OR 0.99; 95% CI: 0.98-0.99). CONCLUSIONS: After surgery, a significant increase in BMD was observed in the lumbar spine and femoral neck. In the multivariate analysis, preoperative bone density was the factor that showed the highest predictive value of the increase in BMD after surgery.

Neuroendocrine Tumor Heterogeneity Adds Uncertainty to the World Health Organization 2010 Classification: Real-World Data from the Spanish Tumor Registry (R-GETNE).

BACKGROUND: Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are a complex family of tumors of widely variable clinical behavior. The World Health Organization (WHO) 2010 classification provided a valuable tool to stratify neuroendocrine neoplasms (NENs) in three prognostic subgroups based on the proliferation index. However, substantial heterogeneity remains within these subgroups, and simplicity sometimes entails an ambiguous and imprecise prognostic stratification. The purpose of our study was to evaluate the prognostic impact of histological differentiation within the WHO 2010 grade (G) 1/G2/G3 categories, and explore additional Ki-67 cutoff values in GEP-NENs. SUBJECTS, MATERIALS, AND METHODS: A total of 2,813 patients from the Spanish National Tumor Registry (RGETNE) were analyzed. Cases were classified by histological differentiation as NETs (neuroendocrine tumors [well differentiated]) or NECs (neuroendocrine carcinomas [poorly differentiated]), and by Ki-67 index as G1 (Ki-67 <2%), G2 (Ki-67 3%-20%), or G3 (Ki-67 >20%). Patients were stratified into five cohorts: NET-G1, NET-G2, NET-G3, NEC-G2, and NEC-G3. RESULTS: Five-year survival was 72%. Age, gender, tumor site, grade, differentiation, and stage were all independent prognostic factors for survival. Further subdivision of the WHO 2010 grading improved prognostic stratification, both within G2 (5-year survival: 81% [Ki-67 3%-5%], 72% [Ki-67 6%-10%], 52% [Ki-67 11%-20%]) and G3 NENs (5-year survival: 35% [Ki-67 21%-50%], 22% [Ki-67 51%-100%]). Five-year survival was significantly greater for NET-G2 versus NEC-G2 (75.5% vs. 58.2%) and NET-G3 versus NEC-G3 (43.7% vs. 25.4%). CONCLUSION: Substantial clinical heterogeneity is observed within G2 and G3 GEP-NENs. The WHO 2010 classification can be improved by including the additive effect of histological differentiation and the proliferation index. IMPLICATIONS FOR PRACTICE: Gastroenteropancreatic neuroendocrine neoplasms are tumors of widely variable clinical behavior, roughly stratified by the World Health Organization (WHO) 2010 classification into three subgroups based on proliferation index. Real-world data from 2,813 patients of the Spanish Registry RGETNE demonstrated substantial clinical heterogeneity within grade (G) 2 and G3 neuroendocrine neoplasms. Tumor morphology and further subdivision of grading substantially improves prognostic stratification of these patients and may help individualize therapy. This combined, additive effect shall be considered in future classifications of neuroendocrine tumors and incorporated for stratification purposes in clinical trials.

Thyroid hormone receptors, cell growth and differentiation.

BACKGROUND: Tissue homeostasis depends on the balance between cell proliferation and differentiation. Thyroid hormones (THs), through binding to their nuclear receptors, can regulate the expression of many genes involved in cell cycle control and cellular differentiation. This can occur by direct transcriptional regulation or by modulation of the activity of different signaling pathways. SCOPE OF REVIEW: In this review we will summarize the role of the different receptor isoforms in growth and maturation of selected tissues and organs. We will focus on mammalian tissues, and therefore we will not address the fundamental role of the THs during amphibian metamorphosis. MAJOR CONCLUSIONS: The actions of THs are highly pleiotropic, affecting many tissues at different developmental stages. As a consequence, their effects on proliferation and differentiation are highly heterogeneous depending on the cell type, the cellular context, and the developmental or transformation status. Both during development and in the adult, stem cells are essential for proper organ formation, maintenance and regeneration. Recent evidence suggests that some of the actions of the thyroid hormone receptors could be secondary to regulation of stem/progenitor cell function. Here we will also include the latest knowledge on the role of these receptors in proliferation and differentiation of embryonic and adult stem cells. GENERAL SIGNIFICANCE: The thyroid hormone receptors are potent regulators of proliferation and differentiation of many cell types. This can explain the important role of the thyroid hormones and their receptors in key processes such as growth, development, tissue homeostasis or cancer. This article is part of a Special Issue entitled Thyroid hormone signalling.

Clinical utility of Phototest via teleneuropsychology in Chilean rural older adults.

The COVID-19 pandemic has shown the need for neuropsychological care for older adults with memory complaints in different contexts, including rural areas or areas with difficult access. Objective: This study aimed to analyze the clinical utility of the Phototest, through telemedicine, to identify mild cognitive impairment in rural older adults with memory complaints, during the COVID-19 pandemic. Methods: We performed a cross-sectional, case-control, and clinical utility comparison of brief cognitive tests (BCTs). The sample included 111 rural elderly people with mild cognitive impairment (MCI) and 130 healthy controls from the Los Lagos region, Chile. The instruments adopted were modified Mini-Mental State Examination (MMSEm) and adapted version of the Phototest (PT) for Chile. Results: To identify mild cognitive impairment, using a cutoff score of 27-28 points, the Phototest showed a sensitivity of 96.6% and a specificity of 81.8%; indicators superior to those of the MMSEm. Conclusions: The Phototest is more accurate than the MMSEm in identifying cognitive alterations in rural older adults with cognitive memory complaints through telemedicine. Therefore, its use in primary care is recommended in order to perform early detection of preclinical cognitive alterations in mild cognitive impairment or neurodegenerative diseases.

A pandemia de COVID-19 mostrou a necessidade de cuidados neuropsicológicos para adultos idosos com queixas de memória em diferentes contextos, incluindo áreas rurais ou áreas de difícil acesso. Objetivo: Analisar a utilidade clínica do Phototest, por meio da telemedicina, para identificar uma leve deficiência cognitiva em adultos idosos rurais com queixas de memória, durante a pandemia de COVID-19. Métodos: Realizamos uma comparação transversal, caso-controle e utilidade clínica dos testes cognitivos breves. Amostra: Cento e onze idosos rurais com deficiência cognitiva leve (DCL) e 130 controles saudáveis da região de Los Lagos, Chile. Instrumentos: Minimental modificado (MMSEm) e versão do teste fotográfico (PT) adaptada para o Chile. Resultados: Para identificar a DCL, usando pontuação de corte de 27-28 pontos, o Phototest mostrou sensibilidade de 96,6% e especificidade de 81,8%; indicadores superiores aos do MMSEm. Conclusões: O Phototest é mais preciso que o MMSEm para identificar, por meio da telemedicina, alterações cognitivas em adultos idosos rurais com queixas de memória cognitiva. Sendo assim, seu uso na atenção primária é recomendado para realizar a detecção precoce de alterações cognitivas pré-clínicas em DCL ou doenças neurodegenerativas.

The tumour suppressor p53 regulates the expression of amyloid precursor protein (APP).

The expression of the APP (amyloid precursor protein), which plays a key role in the development of AD (Alzheimer's disease), is regulated by a variety of cellular mediators in a cell-dependent manner. In this study, we present evidence that p53 regulates the expression of the APP gene in neuroblastoma cells. Transient expression of ectopic p53, activation of endogenous p53 by the DNA-damaging drug camptothecin or Mdm2 (murine double minute 2) depletion decreases the intracellular levels of APP in murine N2abeta neuroblastoma cells. This effect was also observed in primary cultures of rat neurons as well as in SH-SY5Y cells, a human neuroblastoma cell line. Transient transfection studies using plasmids that contain progressive deletions of the 5' region of the gene demonstrate that p53 represses APP promoter activity through a mechanism that is mediated by DNA sequences located downstream of the transcription start site (+55/+101). Accordingly, expression of a dominant-negative p53 mutant significantly increases the transcriptional activity of the APP promoter. In addition, results obtained in gel mobility-shift assays show that p53 does not bind to the +55/+101 APP region, although it reduces binding of the transcription factor Sp1 (stimulating protein 1). Reduction of Sp1 binding after activation of p53 with camptothecin was also observed in chromatin immunoprecipitation assays. Altogether, our results strongly suggest a mechanism by which p53 precludes binding of Sp1 to DNA, and therefore the stimulation of the APP promoter by this transcription factor.

Alpha and beta noradrenergic mediation of NMDA glutamatergic effects on lordosis behaviour and plasmatic LH concentrations in the primed female rat.

In previous studies we have found that blockade of NMDA (N-Methyl-D-Aspartic-Acid)-type glutamatergic receptor with intracerebroventricular (ICV) selective drugs induces an inhibition of lordosis in ovariectomized (OVX) estrogen primed rats receiving progesterone or luteinizing hormone releasing hormone (LHRH). By the opposite way, stimulation with NMDA in OVX estrogen primed rats induced a significant increase of lordosis. In the present study the action of an alpha1-noradrenergic antagonist, HEAT (BE 2254/2-beta-4-Hydroxyphenyl-Ethyl-Aminomethyl-1-Tetralone), and Metoprolol, a beta-noradrenergic antagonist, were studied injecting them ICV previously to NMDA administration in treated OVX estrogen primed rats. In experiment 1, the enhancing effect on lordosis induced by NMDA at high dose (1 microg) was abolished by HEAT administration (P < 0.001 for 3 and 6 microg), and the LH plasma levels were decreased only with the higher dose (P < 0.05), suggesting that behavioral effects are quite more sensitive to the alpha-blockade than hormonal effects. In experiment 2, enhancing effects on lordosis behavior were not observed with neither the NMDA at low dose (0.5 microg) nor the metoprolol alone (5.71 microg), but a synergism was observed when both were simultaneously administered (P < 0.001). The LH plasma levels were increased by Metoprolol alone (P < 0.05), and powered by the combination with NMDA at low dose (P < 0.01 vs. SAL and NMDA alone); no differences were observed with Metoprolol. LH increase was observed with Metoprolol even without behavioural modifications. These findings strongly suggest that facilitatory and inhibitory effects of NMDA in this model are mediated by alpha- and beta-adrenergic transmission in both, behavioral and hormonal effects.

[Grieving among relatives and caregivers]. / Proceso de duelo en familiares y cuidadores.

This article provides a definition and description of grief, its characteristics, and the current explanatory models of this phenomenon (the stage model, task model, constructivist model and dual process model). The authors argue that a state of mourning in advance is produced in the process of dementia as a result of significant relational loss before death and describe the risk factors for complicated grief in caregivers: overload, lack of personal and material resources, delegation of care, and complex feelings such as guilt. The need for healthcare organizations to provide professional caregivers with the appropriate means to help with grief and to develop their own measures to prevent burnout is stressed. These measures could include protocols that provide bereavement intervention with the family, the primary caregiver, other patients and/or residents and the professional caregiving team. Finally, losses in persons with dementia must be taken into consideration, avoiding phenomena such as silencing and overprotection and encouraging acceptance and emotional support of their pain so that organic and emotional complications do not occur.

Evaluation of a Method for Long-Term Cryopreservation of Fungal Strains.

The conservation of microorganisms is essential for their in-depth study. However, today's most widely used conservation methods, based on the use of distilled water, soil, oils, or silica, do not guarantee the stability of fungal cells, especially dermatophytes. This problem led us to evaluate the conservation capacity of a cryogenic vials system containing glass beads covered in a cryopreservant hypertonic solution as an alternative method of storage of fungal cells at -80°C. Up to 570 strains of fungi belonging to 27 different species, isolated from clinical samples, were inoculated into cryotubes containing 25 glass beads covered in a cryopreserving hypertonic solution. Suspensions were mixed vigorously and the cryopreserving solution was discarded. The tubes were frozen at -80°C for a period of 42 months and periodically, a glass bead was removed from each cryotube and inoculated onto Sabouraud dextrose agar, and incubated at 30°C for 7-14 days to evaluate the number of colonies recovered, their purity, and phenotypic characteristics. All yeast isolates were recovered, unlike 2 isolates (4.4%) of the mold group and 21 (10.7%) of the dermatophytes. Survival rates were close to 100% for yeasts and molds, with expiration times being estimated for almost indefinite stocks, and 62% for dermatophytes, with an average expiration date of 25.5 years. The phenotypic characteristics remained comparable to those of the strains before storage. Conservation at -80°C using cryogenic vials is a reliable and efficient system for the conservation of fungal collections, and although the behavior differs by groups, stratified survival data are obtained to avoid extinction.

Erratum to: Short-Term Exposure to Enriched Environment in Adult Rats Restores MK-801-Induced Cognitive Deficits and GABAergic Interneuron Immunoreactivity Loss.

The original version of this article unfortunately contained a mistake. The name of author was changed from "Pascual Gargiulo" to "Pascual Ángel Gargiulo.

Short-Term Exposure to Enriched Environment in Adult Rats Restores MK-801-Induced Cognitive Deficits and GABAergic Interneuron Immunoreactivity Loss.

Perinatal injections of N-methyl-D-aspartate (NMDA) receptor antagonist in rodents emulate some cognitive impairments and neurochemical alterations, such as decreased GABAergic (gamma aminobutyric acid) interneuron immunoreactivity, also found in schizophrenia. These features are pervasive, and developing neuroprotective or neurorestorative strategies is of special interest. In this work, we aimed to investigate if a short exposure to enriched environment (EE) in early adulthood (P55-P73) was an effective strategy to improve cognitive dysfunction and to restore interneuron expression in medial prefrontal cortex (mPFC) and hippocampus (HPC). For that purpose, we administered MK-801 intraperitoneally to Long Evans rats from postnatal days 10 to 20. Twenty-four hours after the last injection, MK-801 produced a transient decrease in spontaneous motor activity and exploration, but those abnormalities were absent at P24 and P55. The open field test on P73 manifested that EE reduced anxiety-like behavior. In addition, MK-801-treated rats showed cognitive impairment in novel object recognition test that was reversed by EE. We quantified different interneuron populations based on their calcium-binding protein expression (parvalbumin, calretinin, and calbindin), glutamic acid decarboxylase 67, and neuronal nuclei-positive cells by means of unbiased stereology and found that EE enhanced interneuron immunoreactivity up to normal values in MK-801-treated rats. Our results demonstrate that a timely intervention with EE is a powerful tool to reverse long-lasting changes in cognition and neurochemical markers of interneurons in an animal model of schizophrenia.

Primary Hyperparathyroidism due to Parathyroid Adenoma Originated from Supernumerary Gland.

INTRODUCTION: The variability of the location of the parathyroid glands is directly related to the events that occur during embryonic development. The impact that an individual submits more than four parathyroid glands is close to 13%. However the presentation of a parathyroid adenoma in a supernumerary gland is an uncommon event. CASE REPORT: A 30-year-old man diagnosed with primary hyperparathyroidism with matching findings on ultrasonography and scintigraphy for parathyroid adenoma localization lower left regarding the thyroid gland. A cervicotomy explorer showed four orthotopic parathyroid glands. The biopsy of the inferior left gland was normal. No signs of adenoma were seen in the biopsy. Following mobilization of the ipsilateral thyroid lobe, fifth parathyroid gland was found increased significantly in size than proceeded to remove, confirming the diagnosis of adenoma. After the excision, the levels of serum calcium and parathyroid hormone were normalized. CONCLUSIONS: The presentation of a parathyroid adenoma in a supernumerary gland is a challenge for the surgeon. The high sensitivity having different imaging techniques has been a key to locate preoperatively the pathological parathyroid gland. Analytical or clinical persistence of primary hyperparathyroidism after parathyroid surgery can occur if the location of the adenoma is a supernumerary or ectopic gland location.

Gene expression profile in beta-amyloid-treated SH-SY5Y neuroblastoma cells.

The beta-amyloid peptide, the major component of the senile plaques in Alzheimer's disease (AD), has been probed to be toxic to neurons both in vivo and in vitro. Several mechanisms have been proposed to be involved in the amyloid-induced neurotoxicity; among others it has been suggested that the beta-amyloid peptide exerts its toxic effect mainly by activating the surrounding microglia population, which in turn induces the synthesis and release of preapoptotic and pro-inflammatory factors. In addition, a direct effect of beta-amyloid on neurons has been also described. However, the precise mechanisms involved in the amyloid-induced neurotoxicity have been not yet definitely clarified. To characterize the effects directly induced on neurons, we have analyzed the gene expression profile induced by the 25-35 beta-amyloid fragment in human SH-SY5Y neuroblastoma cells, by using the Affymetrix GeneChip Human Genome U133 Plus 2.0 Array. Our results confirm that beta-amyloid may directly induce neuronal cell death; activating signals that in vivo have been described as causative of Alzheimer's disease.

Clinical utility of Phototest via teleneuropsychology in Chilean rural older adults / Utilidade clínica do phototest via teleneuropsicologia em idosos rurais chilenos

ABSTRACT. The COVID-19 pandemic has shown the need for neuropsychological care for older adults with memory complaints in different contexts, including rural areas or areas with difficult access. Objective: This study aimed to analyze the clinical utility of the Phototest, through telemedicine, to identify mild cognitive impairment in rural older adults with memory complaints, during the COVID-19 pandemic. Methods: We performed a cross-sectional, case-control, and clinical utility comparison of brief cognitive tests (BCTs). The sample included 111 rural elderly people with mild cognitive impairment (MCI) and 130 healthy controls from the Los Lagos region, Chile. The instruments adopted were modified Mini-Mental State Examination (MMSEm) and adapted version of the Phototest (PT) for Chile. Results: To identify mild cognitive impairment, using a cutoff score of 27-28 points, the Phototest showed a sensitivity of 96.6% and a specificity of 81.8%; indicators superior to those of the MMSEm. Conclusions: The Phototest is more accurate than the MMSEm in identifying cognitive alterations in rural older adults with cognitive memory complaints through telemedicine. Therefore, its use in primary care is recommended in order to perform early detection of preclinical cognitive alterations in mild cognitive impairment or neurodegenerative diseases.

RESUMO. A pandemia de COVID-19 mostrou a necessidade de cuidados neuropsicológicos para adultos idosos com queixas de memória em diferentes contextos, incluindo áreas rurais ou áreas de difícil acesso. Objetivo: Analisar a utilidade clínica do Phototest, por meio da telemedicina, para identificar uma leve deficiência cognitiva em adultos idosos rurais com queixas de memória, durante a pandemia de COVID-19. Métodos: Realizamos uma comparação transversal, caso-controle e utilidade clínica dos testes cognitivos breves. Amostra: Cento e onze idosos rurais com deficiência cognitiva leve (DCL) e 130 controles saudáveis da região de Los Lagos, Chile. Instrumentos: Minimental modificado (MMSEm) e versão do teste fotográfico (PT) adaptada para o Chile. Resultados: Para identificar a DCL, usando pontuação de corte de 27-28 pontos, o Phototest mostrou sensibilidade de 96,6% e especificidade de 81,8%; indicadores superiores aos do MMSEm. Conclusões: O Phototest é mais preciso que o MMSEm para identificar, por meio da telemedicina, alterações cognitivas em adultos idosos rurais com queixas de memória cognitiva. Sendo assim, seu uso na atenção primária é recomendado para realizar a detecção precoce de alterações cognitivas pré-clínicas em DCL ou doenças neurodegenerativas.

A response unit in the first exon of the beta-amyloid precursor protein gene containing thyroid hormone receptor and Sp1 binding sites mediates negative regulation by 3,5,3'-triiodothyronine.

Thyroid hormones repress expression of APP (beta-amyloid precursor protein) in cultured cells of neuronal origin. The effect involves binding to the nuclear thyroid hormone receptor (TR) and is mediated by DNA sequences located within the first exon of the gene. These sequences contain a thyroid hormone response element that is necessary, but not sufficient, to mediate the inhibitory effect of the thyroid hormone T(3). In this report, we show that repression by T(3) is mediated by a response unit composed by the thyroid hormone response element and 5'-flanking sequences that bind Sp1 and mediate stimulation by this transcription factor. In that unit, binding sites for TR and Sp1 overlap and a complex mechanism appears to account for the TR-mediated regulation of APP. Unliganded TR does not bind to DNA and allows Sp1 to bind to DNA and stimulate APP basal expression. Binding of ligand T(3), which increases affinity of TR by DNA, precludes binding of Sp1 to DNA and decreases the Sp1-dependent expression of APP.

3-Hydroxy-3-methyl-glutaryl coenzyme A reductase inhibitors, atorvastatin and simvastatin, induce apoptosis of vascular smooth muscle cells by downregulation of Bcl-2 expression and Rho A prenylation.

The mechanism by which 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) induce apoptosis in vascular smooth muscle cells (VSMCs) is unknown. In this work, we demonstrate that treatment of VSMCs with simvastatin and atorvastatin inhibited Bcl-2 expression in a time and dose-dependent manner, while Bax expression was not modified. This effect was reversed by mevalonate (100 micromol/l), farnesylpyrophosphate (5 micromol/l) or geranylgeranylpyrophosphate (5 micromol/l), suggesting the involvement of protein prenylation. The treatment of VSMCs with lipophilic statins was associated with decreased prenylation of p-21 Rho A and mevalonate, farnesyl pyrophosphate (F-PP) and geranylgeranyl pyrophosphate (G-PP) reversed prenylation to basal levels. In addition, overexpression of constitutively active Q63L Rho A prevented, at least in part, apoptosis induced by statins and downregulation of Bcl-2. We also investigated the participation of caspases (proteases) in the apoptosis induced by statins. The treatment of VSMCs with lipophilic statins induced activation of the caspase 9, the first caspase of the mitochondrial pathway. Coincubation of VSMCs with the caspase inhibitor ZVAD-fmk (100 micromol/l) significantly inhibited lipophilic statin-induced apoptosis. These findings indicate that the downregulation of Bcl-2 by Rho GTPases mediates statin-induced apoptosis and suggest a new potential mechanism of action for these drugs on the regulation of cell number in the atherosclerotic lesions.

Serum is required for release of Alzheimer's amyloid precursor protein in neuroblastoma cells.

The beta-amyloid peptide, the major component of the senile plaques that characterize Alzheimer's disease, is generated from a set of alternatively spliced beta-amyloid precursor proteins (APPs), which are proteolytically cleaved by the action of a set of enzymes referred to generically as secretases. The major processing pathway involves the proteolytic cleavage of APP by alpha-secretase and results in the release of soluble non-amyloidogenic full-length amino terminal fragments (sAPP), which appear to be involved in neurotrophic events. A reduced production of these neuroprotective sAPP would contribute, together with deposition of the beta-amyloid peptide, to the neurodegenerative processes that lead to the cellular death in Alzheimer's disease. In the present work, we describe a dramatic reduction of sAPP content in medium conditioned by neuronal cells grown under low-serum conditions, when compared with the levels released in the presence of 10% serum. The inhibitory effect on sAPP release appears to be quite specific since that reduction occurs without major changes in cell proliferation, expression of APP-mRNA or intracellular APP levels. Under low-serum conditions, cells showed a more differentiated morphology and no apoptotic signs were observed. Since the alpha-secretase has been described as a membrane anchored protein, our results suggest that the serum contains an essential factor(s) involved in the alpha-secretase activity.

Glutamate and modeling of schizophrenia symptoms: review of our findings: 1990-2014.

In the early 90s, we studied the role of perception disturbances in schizophrenia in our first clinical approaches, using the Bender test in schizophrenic patients. Results were clear, showing a shape discrimination failure. Following this initial results, we reproduced nuclear symptoms of schizophrenia in animal models, showing that perceptual disturbances, acquisition disturbances, decrease in affective levels and working memory disturbances can be induced by specific N-methyl-D-aspartic acid (NMDA) glutamatergic blockade within the nucleus accumbens septi (NAS). We studied also another glutamatergic and dopaminergic drugs, finding that a decrease in glutamatergic transmission within NAS led to cognitive disturbances and affective flattening. An increase in glutamatergic transmission fully enhances cognition in the tasks used. Dopaminergic D-2 antagonists partially improved cognition. Our results link the proposed corticostriatal dysfunction with the thalamocortical disturbances underlying perceptual problems, but also influencing affective levels and cognitive variables. According to our translational findings, core schizophrenia symptoms may be translationally reproduced antagonizing NMDA receptors within NAS, and improved blocking the glutamate auto-receptor. Dopaminergic transmission appears to have a role in therapeutic but not in the early pathophysiology of schizophrenia.

The thyroid hormone receptor ß induces DNA damage and premature senescence.

There is increasing evidence that the thyroid hormone (TH) receptors (THRs) can play a role in aging, cancer and degenerative diseases. In this paper, we demonstrate that binding of TH T3 (triiodothyronine) to THRB induces senescence and deoxyribonucleic acid (DNA) damage in cultured cells and in tissues of young hyperthyroid mice. T3 induces a rapid activation of ATM (ataxia telangiectasia mutated)/PRKAA (adenosine monophosphate-activated protein kinase) signal transduction and recruitment of the NRF1 (nuclear respiratory factor 1) and THRB to the promoters of genes with a key role on mitochondrial respiration. Increased respiration leads to production of mitochondrial reactive oxygen species, which in turn causes oxidative stress and DNA double-strand breaks and triggers a DNA damage response that ultimately leads to premature senescence of susceptible cells. Our findings provide a mechanism for integrating metabolic effects of THs with the tumor suppressor activity of THRB, the effect of thyroidal status on longevity, and the occurrence of tissue damage in hyperthyroidism.