Inflammatory bowel disease induces pathological α-synuclein aggregation in the human gut and brain.

AIMS: According to Braak's hypothesis, it is plausible that Parkinson's disease (PD) originates in the enteric nervous system (ENS) and spreads to the brain through the vagus nerve. In this work, we studied whether inflammatory bowel diseases (IBDs) in humans can progress with the emergence of pathogenic α-synuclein (α-syn) in the gastrointestinal tract and midbrain dopaminergic neurons. METHODS: We have analysed the gut and the ventral midbrain from subjects previously diagnosed with IBD and form a DSS-based rat model of gut inflammation in terms of α-syn pathology. RESULTS: Our data support the existence of pathogenic α-syn in both the gut and the brain, thus reinforcing the potential role of the ENS as a contributing factor in PD aetiology. Additionally, we have analysed the effect of a DSS-based rat model of gut inflammation to demonstrate (i) the appearance of P-α-syn inclusions in both Auerbach's and Meissner's plexuses (gut), (ii) an increase in α-syn expression in the ventral mesencephalon (brain) and (iii) the degeneration of nigral dopaminergic neurons, which all are considered classical hallmarks in PD. CONCLUSION: These results strongly support the plausibility of Braak's hypothesis and emphasise the significance of peripheral inflammation and the gut-brain axis in initiating α-syn aggregation and transport to the substantia nigra, resulting in neurodegeneration.

A Preliminary Investigation into Search and Matching for Tumor Discrimination in World Health Organization Breast Taxonomy Using Deep Networks.

Breast cancer is one of the most common cancers affecting women worldwide. It includes a group of malignant neoplasms with a variety of biological, clinical, and histopathologic characteristics. There are more than 35 different histologic forms of breast lesions that can be classified and diagnosed histologically according to cell morphology, growth, and architecture patterns. Recently, deep learning, in the field of artificial intelligence, has drawn a lot of attention for the computerized representation of medical images. Searchable digital atlases can provide pathologists with patch-matching tools, allowing them to search among evidently diagnosed and treated archival cases, a technology that may be regarded as computational second opinion. In this study, we indexed and analyzed the World Health Organization breast taxonomy (Classification of Tumors fifth ed.) spanning 35 tumor types. We visualized all tumor types using deep features extracted from a state-of-the-art deep-learning model, pretrained on millions of diagnostic histopathology images from the Cancer Genome Atlas repository. Furthermore, we tested the concept of a digital "atlas" as a reference for search and matching with rare test cases. The patch similarity search within the World Health Organization breast taxonomy data reached >88% accuracy when validating through "majority vote" and >91% accuracy when validating using top n tumor types. These results show for the first time that complex relationships among common and rare breast lesions can be investigated using an indexed digital archive.

Divergent Effects of Metformin on an Inflammatory Model of Parkinson's Disease.

The oral antidiabetic drug metformin is known to exhibit anti-inflammatory properties through activation of AMP kinase, thus protecting various brain tissues as cortical neurons, for example. However, the effect of metformin on the substantia nigra (SN), the main structure affected in Parkinson's disease (PD), has not yet been studied in depth. Inflammation is a key feature of PD and it may play a central role in the neurodegeneration that takes place in this disorder. The aim of this work was to determine the effect of metformin on the microglial activation of the SN of rats using the animal model of PD based on the injection of the pro-inflammogen lipopolysaccharide (LPS). In vivo and in vitro experiments were conducted to study the activation of microglia at both the cellular and molecular levels. Our results indicate that metformin overall inhibits microglia activation measured by OX-6 (MHCII marker), IKKß (pro-inflammatory marker) and arginase (anti-inflammatory marker) immunoreactivity. In addition, qPCR experiments reveal that metformin treatment minimizes the expression levels of several pro- and anti-inflammatory cytokines. Mechanistically, the drug decreases the phosphorylated forms of mitogen-activated protein kinases (MAPKs) as well as ROS generation through the inhibition of the NADPH oxidase enzyme. However, metformin treatment fails to protect the dopaminergic neurons of SN in response to intranigral LPS. These findings suggest that metformin could have both beneficial and harmful pharmacological effects and raise the question about the potential use of metformin for the prevention and treatment of PD.

M918V RET mutation causes familial medullary thyroid carcinoma: study of 8 affected kindreds.

Germline mutations in codon 918 of exon 16 of the RET gene (M918T) are classically associated with multiple endocrine neoplasia type 2B (MEN 2B) with highly aggressive medullary thyroid cancer (MTC), pheochromocytoma and a unique phenotype. The objectives of this study are to describe the rare M918V RET mutation discovered in 8 MTC kindreds from Brazil lacking the MEN 2B phenotype classically observed in M918T patients and to investigate the presence of a founder effect for this germline mutation. Eight apparently sporadic MTC cases were diagnosed with the germline M918V RET mutation. Subsequently, their relatives underwent clinical and genetic assessment (n = 113), and M918V was found in 42 of them. Until today, 20/50 M918V carriers underwent thyroidectomy and all presented MTC/C-cell hyperplasia; the remainder carriers are on clinical follow-up. None of the M918V carriers presented clinical features of MEN 2B. Their clinical presentation was heterogeneous, and the age at tumor diagnosis ranged from 24 to 59 years. Lymph node metastases were present in 12/20 patients, and presumable distant metastases in 2/20; in contrast, we observed a carrier of up to 87 years of age without evidence of MTC. Ethnographic fieldwork and haplotype analyses suggested that the founder mutation first settled in that area fifteen generations ago and originated from Portugal. Our study is the first to demonstrate the RET M918V mutation co-segregating in 8 familial MTC kindreds with validated evidence of a founder effect. We suggest that M918V MTC should be clinically considered an American Thyroid Association (ATA) moderate-risk category.

Chronic stress alters the expression levels of longevity-related genes in the rat hippocampus.

The molecular mechanisms underlying the negative effects of psychological stress on cellular stress during aging and neurodegenerative diseases are poorly understood. The main objective of this study was to test the effect of chronic psychological stress, and the consequent increase of circulating glucocorticoids, on several hippocampal genes involved in longevity. Sirtuin-1, p53, thioredoxin-interacting protein, and heat shock protein 70 were studied at the mRNA and protein levels in stressed and non-stressed animals. Stress treatment for 10 days decreased sirtuin-1 and heat shock protein 70 levels, but increased levels of p53, thioredoxin-interacting protein and the NADPH oxidase enzyme. Examination of protein expression following two months of stress treatment indicated that sirtuin-1 remained depressed. In contrast, an increase was observed for thioredoxin-interacting protein, heat shock protein 70, p53 and the NADPH oxidase enzyme. The effect of stress was reversed by mifepristone, a glucocorticoid receptor antagonist. These data suggest that chronic stress could contribute to aging in the hippocampus.

Comparison between a multiple daily insulin injection regimen (basal once-daily glargine plus mealtime lispro) and continuous subcutaneous insulin infusion (lispro) using continuous glucose monitoring in metabolically optimized type 1 diabetes patients: A randomized open-labelled parallel study / Comparación entre múltiples dosis de insulina (insulina glargina una vez al día y lispro en las comidas) e infusión subcutánea continua de insulina con monitorización continua de glucosa en pacientes con diabetes tipo 1 metabólicamente optimizados. Estudio randomizado

Background and objective: Advantages of continuous subcutaneous insulin infusion (CSII) over multiple daily injections with glargine (MDI/G) are still uncertain. We compared CSII vs. MDI/G therapy in unselected patients with type 1 diabetes using continuous glucose monitoring (CGSM). The primary end-points were glycaemic control and quality of life (QOL). Methods: A total of 45 patients with long-term diabetes and mean HbA1c values of 8.6 ± 1.8% (70.5 ± 15.4 mmol/mol), previously treated with MDI/NPH, were switched to MDI/G for 6 months and then, unfulfilling therapy CSII indication, were randomly assigned to CSII or MDI/G for another six months. We evaluated QOL (EsDqol) and glycaemic control by measuring HbA1c levels, rate of hypoglycaemia, ketoacidosis and CGSM data. Results: After the first phase (MDI/NPH to MDI/G) there was a significant improvement in total EsDQOL (99.72 ± 18.38 vs. 92.07 ± 17.65; p < 0.028), a 0.5% decrease in HbA1c values (8.4 ± 1.2 vs. 7.9 ± 0.7% [68 ± 9.7 vs. 63 ± 5.5 mmol/mol]; p < 0.032), an improvement in glycaemic variability (standard deviation 66.9 ± 14 vs. 59.4 ± 16 mg/dl; p < 0.05), a decrease in insulin requirements (0.87 ± 0.29 vs. 0.80 ± 0.25 U/kg; p < 0.049), a decrease in number of severe hypoglycaemia episodes (0.44 ± 0.9 vs. 0.05 ± 0.2; p < 0.014), and an increase in periods of normoglycaemia measured with CGSM (15.8 ± 10.9% vs. 23 ± 18.4%; p < 0.003). Six months after randomization, significant improvements were seen in the HbA1c (7.9 ± 0.7 vs. 7 ± 0.6% [63 ± 5.5 vs. 53 ± 4.5 mmol/mol]; p < 0.001) and EsQOL (91.66 ± 22 vs. 84.53 ± 1.63; p < 0.045) only in the CSII group. The HbA1c value was significantly lower when compared with the MDI/G group (CSII 7 ± 0.6% [53 ± 4.5 mmol/mol] vs. MDI/G 7.6 ± 0.9% 59.6 ± 7.7 mmol/mol];p < 0.03). Conclusions: Intensive insulin therapy with CSII vs. MDI/G was associated with better levels of HbA1c in patients with long-term type 1 diabetes (AU)

Introducción y objetivo: Las ventajas de la infusión subcutánea continua de insulina (ISCI) sobre múltiples inyecciones diarias de insulina con glargina (MDI/G) son todavía inciertas. Comparamos ISCI frente a MDI/G en pacientes con diabetes tipo 1 sin indicación de terapia ISCI utilizando la monitorización continua de glucosa (CGSM). Los objetivos primarios fueron el control glucémico y la calidad de vida (QOL). Métodos: Un total de 45 pacientes con diabetes 1 de largo tiempo de evolución y valores medios de HbA1c de 8,6 ± 1,8% (70,5 ± 15,4 mmol/mol), previamente tratados con MDI/NPH, fueron cambiados a MDI/G durante 6 meses y luego sin cumplir criterios clínicos para terapia ISCI asignados aleatoriamente a ISCI o MDI/G durante seis meses. Se evaluó la calidad de vida (EsDqol) y el control de la glucemia mediante la medición de los niveles de HbA1c, la tasa de hipoglucemias, cetoacidosis y datos de CGSM. Resultados: Después de la primera fase (MDI/NPH a MDI/G) hubo una mejora significativa en EsDQOL total (99,72 ± 18,38 vs. 92,07 ± 17,65; p < 0.028), una disminución de 0,5% en los valores de HbA1c (8,4 ± 1,2 vs. 7,9 ± 0,7% [68 ± 9,7 vs. 63 ± 5,5 mmol/mol]; p < 0,032), una mejora en la variabilidad de la glucemia (desviación estándar 66,9 ± 14 vs. 59,4 ± 16 mg/dl; p <0,05), una disminución en las necesidades de insulina (0,87 ± 0,29 vs. 0,80 ± 0,25 U/kg; p <0,049), una disminución en el número de episodios de hipoglucemia grave (0,44 ± 0,9 vs. 0,05 ± 0,2; p <0,014), y un aumento en los periodos de normoglucemia medidos con CGSM (15,8 ± 10,9% vs. 23 ± 18,4%; p <0,003). Seis meses después de la aleatorización, se observaron mejoras significativas en la HbA1c (7,9 ± 0,7 vs. 7 ± 0,6%; [63 ± 5,5 vs. 53 ± 4.5 mmol/mol]; p <0,001) y la calidad de vida (91,66 ± 22 vs. 84,53 ± 1,63; p <0,045) sólo en el grupo ISCI. El valour de HbA1c fue significativamente menor en ISCI en comparación con el grupo MDI/G (CSII 7 ± 0,6% [53 ± 4,5 mmol/mol] vs. MDI/G 7,6 ± 0,9% [59,6 ± 7,7 mmol/mol]; p < 0,03). Conclusiones: La terapia insulínica intensiva con ISCI vs. MDI/G se asoció con mejores niveles de HbA1c en pacientes con diabetes tipo 1 de larga evolución (AU)

Comparison between a multiple daily insulin injection regimen (basal once-daily glargine plus mealtime lispro) and continuous subcutaneous insulin infusion (lispro) using continuous glucose monitoring in metabolically optimized type 1 diabetes patients: A randomized open-labelled parallel study.

BACKGROUND AND OBJECTIVE: Advantages of continuous subcutaneous insulin infusion (CSII) over multiple daily injections with glargine (MDI/G) are still uncertain. We compared CSII vs. MDI/G therapy in unselected patients with type 1 diabetes using continuous glucose monitoring (CGSM). The primary end-points were glycaemic control and quality of life (QOL). METHODS: A total of 45 patients with long-term diabetes and mean HbA1c values of 8.6±1.8% (70.5±15.4mmol/mol), previously treated with MDI/NPH, were switched to MDI/G for 6 months and then, unfulfilling therapy CSII indication, were randomly assigned to CSII or MDI/G for another six months. We evaluated QOL (EsDqol) and glycaemic control by measuring HbA1c levels, rate of hypoglycaemia, ketoacidosis and CGSM data. RESULTS: After the first phase (MDI/NPH to MDI/G) there was a significant improvement in total EsDQOL (99.72±18.38 vs. 92.07±17.65; p<0.028), a 0.5% decrease in HbA1c values (8.4±1.2 vs. 7.9±0.7% [68±9.7 vs. 63±5.5mmol/mol]; p<0.032), an improvement in glycaemic variability (standard deviation 66.9±14 vs. 59.4±16mg/dl; p<0.05), a decrease in insulin requirements (0.87±0.29 vs. 0.80±0.25U/kg; p<0.049), a decrease in number of severe hypoglycaemia episodes (0.44±0.9 vs. 0.05±0.2; p<0.014), and an increase in periods of normoglycaemia measured with CGSM (15.8±10.9% vs. 23±18.4%; p<0.003). Six months after randomization, significant improvements were seen in the HbA1c (7.9±0.7 vs. 7±0.6% [63±5.5 vs. 53±4.5mmol/mol]; p<0.001) and EsQOL (91.66±22 vs. 84.53±1.63; p<0.045) only in the CSII group. The HbA1c value was significantly lower when compared with the MDI/G group (CSII 7±0.6% [53±4.5mmol/mol] vs. MDI/G 7.6±0.9% [59.6±7.7mmol/mol]; p<0.03). CONCLUSIONS: Intensive insulin therapy with CSII vs. MDI/G was associated with better levels of HbA1c in patients with long-term type 1 diabetes.

Synergistic deleterious effect of chronic stress and sodium azide in the mouse hippocampus.

Alzheimer's disease is the most common cause of dementia in the elderly. Although the primary cause of the disease is presently unknown, to date several risk factors have been described. Evidence suggests that one of these risk factors could be chronic stress. The aim of this work is to demonstrate that chronic stress is able to induce Alzheimer's disease features after the administration of nontoxic doses of sodium azide. We found that chronic stress increases the levels of several proteins involved in Alzheimer's disease pathogenesis, such as presenilin 1, presenilin 2, and S100ß, besides inducing the aggregation of Tau, ubiquitin, and ß-amyloid proteins in the hippocampus. More important, our work shows a synergistic effect of stress and sodium azide treatment leading to significant neuronal death in the mouse hippocampus. Our results point out that chronic stress is a risk factor contributing to amplify and accelerate Alzheimer's disease features in the hippocampus.

Integration of a postoperative calcitonin measurement into an anatomical staging system improves initial risk stratification in medullary thyroid cancer.

OBJECTIVE: Staging systems applied to medullary thyroid cancer (MTC) rely on initial clinical and pathological features and do not consider the response to treatment. To determine whether MTC staging can be improved by incorporating the first postoperative calcitonin measurement. PATIENTS AND MEASUREMENTS: Eighty-five patients being monitored for MTC (median follow-up 5 years) were retrospectively classified according to both the American Joint Committee on Cancer (AJCC) and the proposed combined risk stratification system (low, intermediate and high risk), which incorporates the first postoperative calcitonin measurement, using the outcomes no evidence of disease (NED), biochemical evidence of disease, structurally identifiable disease and death. RESULTS: Ninety per cent of AJCC I patients were classified as NED at final follow-up. When we added a postoperative calcitonin measurement, 95% low-risk patients were classified as NED at final follow-up. AJCC stages I and IV were associated, respectively, with no occurrence and a high rate (63%) of structurally identifiable disease. Stages II and III yielded similar predictions of structurally identifiable disease, 13% and 14%, respectively. When we included the postoperative calcitonin level, the patients with structural evidence of disease included none from the low-risk group, 10% from the intermediate group and 63% from the high-risk group. The proportion of variance explained analysis (PVE) was better for the combined risk stratification system (54%) than for the AJCC system alone (32%). CONCLUSION: Including the first postoperative calcitonin measurement with the anatomical staging system can better predict the clinical outcome of patients with MTC and refine the follow-up of these patients.

Identification of risk factors for suffering fear of hypoglycemia in type 1 Diabetes Mellitus patients.

Hypoglycemia is one of the main burdens for type I Diabetes Mellitus (DM I) patients. The consequences of hypoglycemia can be quite unpleasant due to the variety of disagreeable physical and psychological symptoms it triggers. The patient's previous experience with hypoglycemia episodes will condition his psychological reaction to future episodes, promoting behavioral modifications that associate with poor glycemic control and worse prognosis, and even with developing psychological disorders, leading to fear of hypoglycemia (FH). To be able to provide tailored prevention and treatment of patients with FH it is necessary to identify the risk factors in DM I patients. We developed and validated the FH-15 scale, a novel instrument to assess FH, which showed good concurrent and predictive validity in DM I patients. In this work we aim to identify the risk factors for suffering FH by detecting DM I patients with FH using the FH-15 scale and then analyzing the association of clinical and sociodemographic variables. We found that age, needing help to resolve an episode of hypoglycemia, and a perceived lack of social support are risk factors for suffering FH.

Chronic stress as a risk factor for Alzheimer's disease.

This review aims to point out that chronic stress is able to accelerate the appearance of Alzheimer's disease (AD), proposing the former as a risk factor for the latter. Firstly, in the introduction we describe some human epidemiological studies pointing out the possibility that chronic stress could increase the incidence, or the rate of appearance of AD. Afterwards, we try to justify these epidemiological results with some experimental data. We have reviewed the experiments studying the effect of various stressors on different features in AD animal models. Moreover, we also point out the data obtained on the effect of chronic stress on some processes that are known to be involved in AD, such as inflammation and glucose metabolism. Later, we relate some of the processes known to be involved in aging and AD, such as accumulation of ß-amyloid, TAU hyperphosphorylation, oxidative stress and impairement of mitochondrial function, emphasizing how they are affected by chronic stress/glucocorticoids and comparing with the description made for these processes in AD. All these data support the idea that chronic stress could be considered a risk factor for AD.

Development and application of a novel sensitive immunometric assay for calcitonin in a large cohort of patients with medullary and differentiated thyroid cancer, thyroid nodules, and autoimmune thyroid diseases.

BACKGROUND: Serum calcitonin (sCT) is a useful biomarker for medullary thyroid cancer (MTC). Consensus has not been reached concerning sCT measurements in the evaluation of nodular thyroid disease (NTD). OBJECTIVE AND METHODS: We developed a new immunofluorometric assay for sCT and have validated it in samples from 794 patients [203 with MTC, 205 with autoimmune thyroid disease (ATD), 248 with NTD, 80 with differentiated thyroid cancer (DTC) 'free of disease', 58 with chronic renal failure (CRF)] and 178 normal individuals, including samples after pentagastrin tests and samples from the washout of 92 FNA procedures in patients with NTD or MTC. We also compared some samples from patients with low or high calcitonin levels using both this assay and the Nichols Institute Diagnostics (NID) assay. RESULTS: The assay's analytical sensitivity was 1.0 pg/ml. Considering MTC patients prior to surgery, the cut-off values for the 95% reference range were 11.1 pg/ml for males and 5.5 pg/ml for females and employing the ROC curve were 18.4 pg/ml for males and 7.8 pg/ml for females. sCT in patients with MTC was strongly correlated with disease status. Patients with NTD and ATD did not present false-positive results. sCT measurements were significantly correlated with age (excluding MTC and CRF). The NID test had a strong correlation with our assay. A hook effect was observed only with concentrations >200,000 pg/ml. CONCLUSIONS: We developed a novel sCT assay and validated it in healthy subjects, as well as in a large cohort of patients with MTC, NTD, ATD, DTC, and CRF.

Role of dopamine in the recruitment of immune cells to the nigro-striatal dopaminergic structures.

Research indicates that inflammation and microglial activation are involved in the initiation and progression of Parkinson's disease (PD). Neuroinflammation contributes to the infiltration of peripheral immune cells and blood-brain barrier (BBB) leakage, linking peripheral and central inflammatory events in the pathogenesis of PD. Dopamine (DA) likely plays a role in this process. In the present study, the dopaminergic toxin 6-hydroxydopamine (6-OHDA) was used to damage dopaminergic neurons. Injection of 6-OHDA within the nigrostriatal pathway produced loss of astrocytes, disruption of the BBB, microglia activation and a reduction in osteopontin (OPN) immunoreactivity. Depletion of DA content by alpha-methylparatyrosine (α-MPT, a tyrosine hydroxylase inhibitor) reduced the infiltration of peripheral macrophages as well as the 6-OHDA-induced increase in microglial cells. DA could therefore be relevant in sustaining inflammation and lymphocyte recruitment induced by 6-OHDA, supporting DA implication in the degeneration of dopaminergic neurons induced by inflammatory processes.

Chronic stress enhances microglia activation and exacerbates death of nigral dopaminergic neurons under conditions of inflammation.

BACKGROUND: Parkinson's disease is an irreversible neurodegenerative disease linked to progressive movement disorders and is accompanied by an inflammatory reaction that is believed to contribute to its pathogenesis. Since sensitivity to inflammation is not the same in all brain structures, the aim of this work was to test whether physiological conditions as stress could enhance susceptibility to inflammation in the substantia nigra, where death of dopaminergic neurons takes place in Parkinson's disease. METHODS: To achieve our aim, we induced an inflammatory process in nonstressed and stressed rats (subject to a chronic variate stress) by a single intranigral injection of lipopolysaccharide, a potent proinflammogen. The effect of this treatment was evaluated on inflammatory markers as well as on neuronal and glial populations. RESULTS: Data showed a synergistic effect between inflammation and stress, thus resulting in higher microglial activation and expression of proinflammatory markers. More important, the higher inflammatory response seen in stressed animals was associated with a higher rate of death of dopaminergic neurons in the substantia nigra, the most characteristic feature seen in Parkinson's disease. This effect was dependent on glucocorticoids. CONCLUSIONS: Our data demonstrate that stress sensitises midbrain microglia to further inflammatory stimulus. This suggests that stress may be an important risk factor in the degenerative processes and symptoms of Parkinson's disease.

A ten-year clinical update of a large RET p.Gly533Cys kindred with medullary thyroid carcinoma emphasizes the need for an individualized assessment of affected relatives.

OBJECTIVE: Reviewing the clinical outcomes of a large kindred with a RET p.Gly533Cys mutation, 10 years after the first description of this kindred, has provided an important set of clinical data for healthcare decision-making. DESIGN AND PATIENTS: We identified 728 RET533 Brazilian relatives, spread out over 7 generations. We performed clinical examination, biochemical and imaging analyses in the proband and in 103 carriers. MEASUREMENT AND RESULTS: The proband has been followed without evidence of structural disease in the last 10 years but with elevated calcitonin. The clinical and surgical features of 60 thyroidectomized RET533 relatives were also described. Forty-six patients had MTC (21-72 years), and 11 patients had C-cell hyperplasia (CCH) (5-42 years). Twelve MTC patients with lymph node metastases had a tumour size of 0·7-2·8 cm. Calcitonin level and CEA were correlated with disease stage, and none of the patients presented with an altered PTH or metanephrine. A 63-year-old woman developed pheochromocytoma and breast cancer. Two other RET533 relatives developed lung squamous cell carcinoma and melanoma. CONCLUSIONS: A vast clinical variability in RET533 presentation was observed, ranging from only an elevated calcitonin level (3%) to local metastatic disease (25%). Many individuals were cured (42%) and the majority had controlled chronic disease (56%), reinforcing the need for individualized ongoing risk stratification assessment. The importance of this update relies on the fact that it allows us to delineate the natural history of RET 533 MEN2A 10 years after its first description.

In vitro and in vivo protection by melatonin against the decline of elongation factor-2 caused by lipid peroxidation: preservation of protein synthesis.

As organisms age, a considerable decrease in protein synthesis takes place in all tissues. Among the possible causes of the decline of translation in old animals are the modifications of elongation factor-2 (eEF-2). eEF-2 occupies an essential role in protein synthesis where it catalyzes the ribosomal translocation reaction. eEF-2 is particularly sensitive to increased oxidative stress. However, all oxidants do not affect eEF-2, only compounds that increase lipid peroxidation. As peroxides are unstable compounds, they decompose and generate a series of highly reactive compounds, including aldehydes malondialdehyde (MDA) and 4-hydroxynoenal (HNE). We have previously reported that hepatic eEF-2 forms adducts with low-molecular weight aldehydes, MDA and HNE. Therefore, the protection of eEF-2 must be specifically carried out by a compound with lipoperoxyl radical-scavenging features such as melatonin. In this article, we show the ability of melatonin to protect against the changes that occur in the eEF-2 under conditions of lipid peroxidation induced by cumene hydroperoxide (CH), a compound used experimentally to induce lipid breakdown. As experimental models, we used cultured cells and rats treated with this oxidant compound. eEF-2 levels, adduct formation of this protein with MDA and HNE, and lipid peroxides were determined. In the cultured cells, protein synthesis rate was also measured. Our results show that melatonin prevented the molecular changes in eEF-2 and the decline in protein synthesis rate secondary to lipid peroxidation. The results also show that serum levels of several hormones were affected by CH-induced oxidative stress, which was partially or totally prevented by melatonin.

Peripheral inflammation increases the deleterious effect of CNS inflammation on the nigrostriatal dopaminergic system.

Evidence supports the role of inflammation in the development of neurodegenerative diseases. In this work, we are interested in inflammation as a risk factor by itself and not only as a factor contributing to neurodegeneration. We tested the influence of a mild to moderate peripheral inflammation (injection of carrageenan into the paws of rats) on the degeneration of dopaminergic neurons in an animal model based on the intranigral injection of lipopolysaccharide (LPS), a potent inflammatory agent. Overall, the treatment with carrageenan increased the effect of the intranigral injection of LPS on the loss of dopaminergic neurons in the SN along with all the other parameters studied, including: serum levels of the inflammatory markers TNF-α, IL-1ß, IL-6 and C-reactive protein; activation of microglia, expression of proinflammatory cytokines, the adhesion molecule ICAM and the enzyme iNOS, loss of astrocytes and damage to the blood brain barrier (BBB). The possible implication of BBB rupture in the increased loss of dopaminergic neurons has been studied using another Parkinson's disease animal model based on the intraperitoneal injection of rotenone. In this experiment, loss of dopaminergic neurons was also strengthened by carrageenan, without affecting the BBB. In conclusion, our data show that a mild to moderate peripheral inflammation can exacerbate the degeneration of dopaminergic neurons caused by a harmful stimulus.

Development of a new fear of hypoglycemia scale: FH-15.

Hypoglycemia is the most common adverse event associated with insulin treatment in diabetes. The consequences of hypoglycemia can be quite aversive and potentially life threatening. The physical sequelae provide ample reason for patients to fear hypoglycemia and avoid episodes. For these reasons, our purpose in this study was to develop a new measure that explores specific fear of hypoglycemia (FH) in adult patients with type 1 diabetes and to examine its psychometric properties. The instrument developed to assess FH was initially made up of 20 items, of which 18 were negative and 2 were positive, assessed on a 5-point Likert scale (1-5). This scale was completed by 229 patients with type 1 diabetes. Additionally, a structured interview and a closed question called subjective fear of hypoglycemia were included as diagnostic criteria. A factor analysis employing the principal-components method and promax rotation was carried out, resulting in a new scale composed of 15 items. Three factors (fear, avoidance, and interference) were obtained and explained 58.27% of the variance. The scale showed good internal consistency (Cronbach's α = .891) and test-retest reliability (r = .908, p < .001), as well as adequate concurrent and predictive validity. The cutoff score that provided the highest overall sensitivity and specificity was set at 28 points. The Fear of Hypoglycemia 15-item scale (FH-15) demonstrated good reliability and validity. This study suggests that the new instrument may serve as a valuable measure of specific FH for use in research and clinical practice.

Effect of aging and oxidative stress on elongation factor-2 in hypothalamus and hypophysis.

The hypothalamic-hypophysis system (HHS) secretes peptide hormones whose synthesis requires the integrity of the translation machinery. As the organisms age, a considerable diminution of the protein synthesis takes place in several tissues. Among the possible causes of the decline of translation in old animals are the modifications of elongation factor-2 (eEF-2). We studied whether the level of this protein was affected in the HHS in old animals. The effects of aging are compared to those of an oxidant compound (cumene hydroperoxide) administered to young rats. The results indicate that oxidative stress could be involved in the alterations of eEF-2, which forms adducts with malondialdehyde (MDA) and 4-hydroxynonenal (HNE). The alterations of eEF-2 levels, secondary to lipid peroxidation and adduct formation with these aldehydes could contribute to the suboptimal hormone production from these tissues during aging. Besides eEF-2, proteomic analysis shows that several other proteins are affected.

Striatal ablation of GABAergic neurons prevents the in vivo neuroprotective effect of DCG-IV against the MPP+-induced neurotoxicity on dopaminergic nerve terminals.

In previous studies we found that intrastriatal DCG-IV administration, an agonist for group II metabotropic glutamate receptor: (i) protected striatal dopaminergic terminals against MPP(+)-induced neurotoxicity (Matarredona et al., 2001); (ii) selectively destroyed striatal GABAergic neurons (Venero et al., 2002) and (iii) induced early robust up-regulation of brain-derived neurotrophic factor (BDNF) in nigral dopaminergic neurons afferents in a target-dependent manner (Rite et al., 2005). Considering that BDNF protein is anterogradely transported to dopaminergic nerve endings, an autocrine role of BDNF could account for the neuroprotective effect of DCG-IV against the MPP(+)-induced toxicity of dopaminergic terminals. To test this possibility, we first performed a previous insult with quinolinic acid (QA) to specifically damage the striatal GABAergic neuronal cell bodies in order to remove the nigral BDNF target. Fourteen days later, we explored the potential in vivo neuroprotective action of DCG-IV against MPP(+)-induced toxicity on striatal dopaminergic nerve terminals by in vivo microdialysis. Integrity of GABAergic system was evaluated by glutamic acid decarboxylase (GAD) in situ hybridization. We demonstrate that previous striatal target ablation with QA prevented the neuroprotective effect of DCG-IV perfusion against the MPP(+)-induced neurotoxicity on dopaminergic terminals. Our results strongly suggest an important autocrine neuroprotective role of BDNF on striatal dopaminergic nerve terminals. In addition, we found an unexpected regulatory response of surviving striatal GABAergic neurons in terms of high levels of GAD mRNA expression.