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1.
Food Technol Biotechnol ; 61(2): 259-270, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37457912

ABSTRACT

Research background: The production of foods fortified with bioactive ingredients has been recognized by food companies as a way to position their products in health food markets. The fortification of cheese represents a major challenge, due to the chemical and structural complexity of the cheese matrix, as well as the complexity of the biochemical reactions occurring during the fermentation and maturation processes. Microalgae are nutritious and sustainable food sources with important bioactive compounds such as proteins, polyunsaturated fatty acids, polysaccharides, chlorophylls, carotenoids, vitamins and minerals. Experimental approach: This work aims to study the impact of the 2 and 4 % microalga Chlorella vulgaris addition on the nutritional composition, bioactivity, structure and sensory profile of quark and cream cheese, both probiotic fermented products. Texture profile analysis and fundamental rheology measurements (oscillatory and stationary) were performed to evaluate the impact of C. vulgaris on the mechanical properties of the fresh cheese. The nutritional composition was evaluated using standard methods and bioactivity through the determination of total phenolic compounds and antioxidant capacity.1. Results and conclusions: C. vulgaris had an impact on the firmness of both cheeses. In general, the cheese with added C. vulgaris had a better nutritional profile, with an increase in protein content, content of Mg, P, S, Cu, Zn, Fe and Mn, and better bioactivity with an increase in the antioxidant activity. Sensory testing results were promising, especially for cream cheese. Novelty and scientific contribution: The enrichment of traditional foods such as fresh cheese with microalgae represents an interesting strategy to develop hybrid products (with protein from animal and vegetable sources), obtain innovative and more sustainable products, and improve their nutritional profile in terms of protein and mineral content and bioactivity.

2.
Ann Hepatobiliary Pancreat Surg ; 27(1): 102-106, 2023 Feb 28.
Article in English | MEDLINE | ID: mdl-36003000

ABSTRACT

Hepatocellular carcinoma (HCC) accounts for most of the hepatic neoplasms and can also occur in ectopic liver tissue. We present a case of a 55-year-old male complaining of weight loss. The imaging studies reported a 2.9 cm nodule in the pancreatic body, with a neuroendocrine tumor diagnosis by cytology. A corpo-caudal pancreatectomy was performed. Pathology showed a well-differentiated HCC developed in ectopic liver tissue with free margins and no lymph node metastases. HCC presenting in ectopic liver tissue is rare. In this case, the preoperative study did not establish the diagnosis, warranting the need for suspicion of this neoplasm.

3.
Cir Esp (Engl Ed) ; 100(2): 81-87, 2022 Feb.
Article in English | MEDLINE | ID: mdl-35123939

ABSTRACT

INTRODUCTION: Management of positive sentinel lymph node biopsy (SLNB) in breast cancer remains a matter of debate. Our aim was to evaluate the incidence and identify predictive factors of non-sentinel lymph node metastases. METHODS: Retrospective review of all cN0 breast cancer patients treated between January 2013 and December 2017, with positive SLNB that were submitted to ALND. RESULTS: Of the 328 patients included, the majority of tumors were cT1 or cT2, with lymphovascular invasion in 58.4% of cases. The mean isolated nodes in SLNB was 2.7, with a mean of 1.6 positive nodes, 60.7% with extracapsular extension. Regarding ALND, a mean of 13.9 nodes were isolated, with a mean of 2.1 positive nodes. There was no residual disease in the ALND in 50.9% of patients, with 18.9% having ≥4 positive nodes. In the multivariate analysis, lymphovascular invasion, extracapsular extension in SLN, largest SLN metastases size (>10 mm) and ratio of positive SNL (>50%) were independent predictors of non-sentinel lymph node metastases. These four factors were used to build a non-pondered score to predict the probability of a positive ALND after a positive SLNB. The AUC of the model was 0.69 and 81% of patients with score = 0 and 65.6% with score = 1 had no additional disease in ALND. CONCLUSION: The absence of non-sentinel lymph node metastases in the majority of patients with 1-2 positive SLN with low risk score questions the need of ALND in this population. The identified predictive factors may help select patients in which ALND can be omitted.


Subject(s)
Breast Neoplasms , Sentinel Lymph Node , Breast Neoplasms/surgery , Female , Humans , Lymph Node Excision , Retrospective Studies , Sentinel Lymph Node Biopsy
4.
Cir. Esp. (Ed. impr.) ; 100(2): 81-87, febr,. 2022. tab, graf
Article in Spanish | IBECS | ID: ibc-202992

ABSTRACT

Introducción: Manejo del ganglio centinela positivo en cáncer de mama sigue siendo un tema de debate. El objetivo es evaluar la incidencia e identificar los factores predictivos de metástasis en ganglios no centinela. Métodos: Revisión retrospectiva de los pacientes con cáncer de mama con axila clínicamente negativa (cN0) tratados entre enero del 2013 y diciembre del 2017, con biopsia de ganglio centinela (BGC) positiva a quienes se les realizó linfadenectomía axilar (LA). Resultados: De los 328 pacientes incluidos, la mayoría tenía tumores cT1 o cT2, con invasión linfovascular en el 58,4% de casos. La media de ganglios detectados en BGC fue 2,7, con una media de 1,6 ganglios positivos, el 60,7% con extensión extracapsular. En LA, una media de 13,9 ganglios fueron detectados, con media de 2,1 ganglios positivos. No se observó metástasis en LA en el 50,9% de los pacientes y el 18,9% tenía ≥ cuatro ganglios positivos. En análisis multivariado, la invasión linfovascular, la extensión extracapsular, la dimensión de mayor metástasis (>10 mm) y la ratio de ganglios centinela positivos (> 50%) fueron factores predictivos independientes de metástasis en ganglios no centinela. Estos factores fueron usados para construir un score para predecir la posibilidad de LA positiva después de BGC positiva. El área bajo la curva ROC (AUC) del modelo fue 0,69 y el 81% de los pacientes con score = 0, y el 65,6% con score = 1 no tenían metástasis en la LA. Conclusión: La ausencia de metástasis en ganglios no centinela en la mayoría de los casos con uno a dos ganglios positivos en la BGC con score de bajo riesgo cuestiona la necesidad de hacer LA en estos pacientes. Los factores predictivos identificados pueden ayudar a seleccionar pacientes para omitir la LA (AU)


Introduction: Management of positive sentinel lymph node biopsy (SLNB) in breast cancer remains a matter of debate. Our aim was to evaluate the incidence and identify predictive factors of non-sentinel lymph node metastases. Methods: Retrospective review of all cN0 breast cancer patients treated between January 2013 and December 2017, with positive SLNB that were submitted to ALND.ResultsOf the 328 patients included, the majority of tumors were cT1 or cT2, with lymphovascular invasion in 58.4% of cases. The mean isolated nodes in SLNB was 2.7, with a mean of 1.6 positive nodes, 60.7% with extracapsular extension. Regarding ALND, a mean of 13.9 nodes were isolated, with a mean of 2.1 positive nodes. There was no residual disease in the ALND in 50.9% of patients, with 18.9% having ≥ four positive nodes. In the multivariate analysis, lymphovascular invasion, extracapsular extension in SLN, largest SLN metastases size (>10 mm) and ratio of positive SNL (> 50%) were independent predictors of non-sentinel lymph node metastases. These four factors were used to build a non-pondered score to predict the probability of a positive ALND after a positive SLNB. The AUC of the model was 0.69 and 81% of patients with score = 0 and 65.6% with score = 1 had no additional disease in ALND. Conclusion: The absence of non-sentinel lymph node metastases in the majority of patients with 1-2 positive SLN with low risk score questions the need of ALND in this population. The identified predictive factors may help select patients in which ALND can be omitted (AU)


Subject(s)
Humans , Female , Adult , Middle Aged , Aged , Aged, 80 and over , Breast Neoplasms/pathology , Breast Neoplasms/surgery , Sentinel Lymph Node Biopsy , Predictive Value of Tests , Neoplasm Staging , Lymphatic Metastasis , Lymph Node Excision , Prognosis
5.
Cir Esp (Engl Ed) ; 2020 Dec 21.
Article in English, Spanish | MEDLINE | ID: mdl-33358014

ABSTRACT

INTRODUCTION: Management of positive sentinel lymph node biopsy (SLNB) in breast cancer remains a matter of debate. Our aim was to evaluate the incidence and identify predictive factors of non-sentinel lymph node metastases. METHODS: Retrospective review of all cN0 breast cancer patients treated between January 2013 and December 2017, with positive SLNB that were submitted to ALND. RESULTS: Of the 328 patients included, the majority of tumors were cT1 or cT2, with lymphovascular invasion in 58.4% of cases. The mean isolated nodes in SLNB was 2.7, with a mean of 1.6 positive nodes, 60.7% with extracapsular extension. Regarding ALND, a mean of 13.9 nodes were isolated, with a mean of 2.1 positive nodes. There was no residual disease in the ALND in 50.9% of patients, with 18.9% having ≥ four positive nodes. In the multivariate analysis, lymphovascular invasion, extracapsular extension in SLN, largest SLN metastases size (>10 mm) and ratio of positive SNL (> 50%) were independent predictors of non-sentinel lymph node metastases. These four factors were used to build a non-pondered score to predict the probability of a positive ALND after a positive SLNB. The AUC of the model was 0.69 and 81% of patients with score = 0 and 65.6% with score = 1 had no additional disease in ALND. CONCLUSION: The absence of non-sentinel lymph node metastases in the majority of patients with 1-2 positive SLN with low risk score questions the need of ALND in this population. The identified predictive factors may help select patients in which ALND can be omitted.

6.
Endoscopy ; 51(1): 30-39, 2019 01.
Article in English | MEDLINE | ID: mdl-29969807

ABSTRACT

BACKGROUND: There are no prospective studies comparing endoscopic submucosal dissection (ESD) and gastrectomy, especially evaluating patient-reported outcomes. Our aim was to compare the safety and impact on quality of life (QoL) of ESD and gastrectomy in patients with early gastric neoplasia. METHODS: This prospective study included consecutive patients presenting with early gastric neoplasia in a tertiary center from January 2015 to August 2016. Data collection included curative resection, adverse events (AEs), and patient-reported outcomes (questionnaires: EORTC QLQ-C30, EORTC STO-22, EQ-5D-5 L, and Assessment of Survivor Concerns) before and after interventions (after 1 month, 3 - 6 months, and 1 year). RESULTS: 254 patients with early lesions were included: 153 managed by ESD and 101 by gastrectomy, the former being significantly older and with less advanced lesions. Mean procedural time and length of stay were significantly higher in the surgery group (164 vs. 72 minutes and 16.3 vs. 3.5 days; P < 0.001). Complete resection was higher in the surgical group (99 % vs. 90 %; P = 0.02); ESD was curative in 79 % of patients. Severe AEs and surgical re-intervention were significantly more frequent in the gastrectomy group (21.8 % vs. 7.8 % and 11 % vs. 1 %, respectively). Endoscopic treatment was associated with a positive impact on global health-related QoL at 1 year (net difference + 9.9; P = 0.006), role function and symptom scales (fatigue, pain, appetite, eating restrictions, dysphagia, and body image). Concerns about recurrence did not differ between the groups. CONCLUSIONS: In patients with early gastric neoplasia, ESD is safer and is associated with a positive impact on health-related QoL when compared with gastrectomy, without increasing fear of recurrence and new lesions.


Subject(s)
Endoscopic Mucosal Resection , Gastrectomy , Quality of Life , Stomach Neoplasms , Early Medical Intervention/methods , Endoscopic Mucosal Resection/adverse effects , Endoscopic Mucosal Resection/methods , Endoscopic Mucosal Resection/psychology , Female , Gastrectomy/adverse effects , Gastrectomy/methods , Gastrectomy/psychology , Humans , Male , Middle Aged , Neoplasm Recurrence, Local/psychology , Neoplasm Staging , Outcome and Process Assessment, Health Care , Patient Reported Outcome Measures , Portugal , Prospective Studies , Stomach Neoplasms/pathology , Stomach Neoplasms/physiopathology , Stomach Neoplasms/psychology , Stomach Neoplasms/surgery
7.
J Alzheimers Dis ; 44(3): 949-62, 2015.
Article in English | MEDLINE | ID: mdl-25374107

ABSTRACT

Macrophages are key cells in tissue defense in the periphery and, under certain circumstances, infiltrate the central nervous system, where they may play a similar role in the brain, perhaps supporting the function of microglia. Macrophages have been shown to adopt different activation states in response to various stimuli. Specifically, when exposed to inflammatory stimuli such as interferon (IFN)γ, the cells adopt the M1 phenotype, whereas when exposed to anti-inflammatory cytokines such as interleukin (IL)-4 or IL-13, the M2 phenotype is adopted. While M1 macrophages are associated with tissue defense and destruction of invading pathogens, M2 macrophages are involved in tissue repair and in terminating inflammation. It is well known that an inflammatory microenvironment exists in the brain of aged animals and also in the brain of mice that overexpress amyloid-ß protein precursor (AßPP) and presenilin 1 (PS1; AßPP/PS1 mice), a commonly-used model of Alzheimer's disease (AD). Recent studies have revealed that immune cells, including macrophages, infiltrate the brain in both circumstances raising the possibility that these cells adopt the M1 activation state and contribute to the already-existing neuroinflammation. We set out to examine the responses of bone marrow-derived macrophages prepared from wildtype and AßPP/PS1 mice and demonstrate that cells from AßPP/PS1 mice, even after several days in culture, respond more profoundly to IFNγ than those from wildtype mice. We suggest that this propensity to respond to M1-polarizing stimuli, together with the described changes in the brain of AßPP/PS1 mice, contribute to the development of chronic neuroinflammation.


Subject(s)
Alzheimer Disease/pathology , Gene Expression Regulation/drug effects , Gene Expression Regulation/genetics , Interferon-gamma/pharmacology , Macrophages/drug effects , Alzheimer Disease/genetics , Amyloid beta-Protein Precursor/genetics , Animals , Brain/drug effects , Brain/metabolism , Cells, Cultured , Claudin-5/metabolism , Cytokines/metabolism , Disease Models, Animal , Endothelium/drug effects , Female , Humans , Male , Membrane Glycoproteins/metabolism , Mice , Mice, Inbred C57BL , Mice, Transgenic , Neutrophil Infiltration/drug effects , Neutrophil Infiltration/genetics , Presenilin-1/genetics , Receptors, Cell Surface/metabolism , Receptors, Immunologic , Zonula Occludens-1 Protein/metabolism
8.
Korean J Parasitol ; 52(6): 613-9, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25548412

ABSTRACT

Neospora caninum (Apicomplexa; Sarcocystidae) is a protozoan that causes abortion in cattle, horses, sheep, and dogs as well as neurological and dermatological diseases in dogs. In the central nervous system of dogs infected with N. caninum, cysts were detected that exhibited gliosis and meningitis. Flavonoids are polyphenolic compounds that exhibit antibacterial, antiparasitic, antifungal, and antiviral properties. In this study, we investigated the effects of flavonoids in a well-established in vitro model of N. caninum infection in glial cell cultures. Glial cells were treated individually with 10 different flavonoids, and a subset of cultures was also infected with the NC-1 strain of N. caninum. All of the flavonoids tested induced an increase in the metabolism of glial cells and many of them increased nitrite levels in cultures infected with NC-1 compared to controls and uninfected cultures. Among the flavonoids tested, 3',4'-dihydroxyflavone, 3',4',5,7-tetrahydroxyflavone (luteolin), and 3,3',4',5,6-pentahydroxyflavone (quercetin), also inhibited parasitophorous vacuole formation. Taken together, our findings show that flavonoids modulate glial cell responses, increase NO secretion, and interfere with N. caninum infection and proliferation.


Subject(s)
Flavonoids/pharmacology , Immunologic Factors/pharmacology , Neospora/drug effects , Neospora/growth & development , Neuroglia/drug effects , Neuroglia/parasitology , Animals , Cells, Cultured , Rats, Wistar
9.
Front Cell Neurosci ; 8: 340, 2014.
Article in English | MEDLINE | ID: mdl-25386119

ABSTRACT

Neospora caninum causes cattle abortion and neurological symptoms in dogs. Although infection is usually asymptomatic, classical neurological symptoms of neosporosis may be associated with encephalitis. This parasite can grow in brain endothelial cells without markedly damages, but it can modulate the cellular environment to promote its survival in the brain. In previous studies, we described that IFN-γ decreased the parasite proliferation and down regulated nitric oxide (NO) production in astrocyte/microglia cultures. However, it remains unclear how glial cells respond to N. caninum in the presence of neurons. Therefore, we evaluated the effect of 300 IU/mL IFN-γ or 1.0 mg/mL of LPS on infected rat neuron/glial co-cultures. After 72 h of infection, LPS did not affect the mitochondrial dehydrogenase activity. However, IFN-γ decreased this parameter by 15.5 and 12.0% in uninfected and infected cells, respectively. The number of tachyzoites decreased 54.1 and 44.3% in cells stimulated with IFN-γ and LPS, respectively. Infection or LPS treatment did not change NO production. On the other hand, IFN-γ induced increased nitrite release in 55.7%, but the infection reverted this induction. IL-10 levels increased only in infected cultures (treated or not), meanwhile PGE2 release was improved in IFN-γ/infected or LPS/infected cells. Although IFN-γ significantly reduced the neurite length in uninfected cultures (42.64%; p < 0.001), this inflammatory cytokine reverted the impairment of neurite outgrowth induced by the infection (81.39%). The results suggest a neuroprotective potential response of glia to N. caninum infection under IFN-γ stimulus. This observation contributes to understand the immune mediated mechanisms of neosporosis in central nervous system (CNS).

10.
Nat Prod Commun ; 9(9): 1245-8, 2014 Sep.
Article in English | MEDLINE | ID: mdl-25918783

ABSTRACT

Plant secondary metabolites, such as, specifically, alkaloids and terpenes, may present psychoactive properties that modify the function of the central nervous system (CNS) and induce neurotoxicity. Neurotoxicity involves the response of glial cells, mainly astrocytes, which play a fundamental role in the control of homeostasis of the CNS. Some Erythroxylum species are indigenous to the state of Bahia in Brazil. This study investigated the cytotoxic activity of the diterpene AEP-1, extracted from the fruit of E. passerinum in a GL-15 cell line, astrocytic, glial cells model. The effects on cell viability, analyzed by the MTT assay, demonstrated a dose-dependent cytotoxic effect, with maximum effect at 500 µg/mL of AEP-1, and with a reduction of about 40 and 47% on cellular viability after 24 h and 72 h treatment, respectively. Evidence for induction of apoptosis by AEP-1 was first obtained when GL-15 glial cells were incubated with 250 µg/mL AEP-1 causing reniform and/or pyknotic nuclei and apoptotic bodies revealed by chromatin staining with Hoechst 33258. Increase in DNA fragmentation was also observed by comet assays in cells incubated with 500 µg/mL of AEP-1. Moreover, cells exposed to a sub toxic dose of AEP-1 (250 µg/mL) showed significant changes in morphology--contraction of the cytoplasm and expansion of cellular projections--signifying the presence of astrocytic cytoskeletal protein and glial fibrillary acidic protein (GFAP). These findings indicated astrocytic cells as the target for terpene AEP-1 and suggest the involvement of glial cells with psychoactive symptoms observed in humans and animals after consumption of fruits of plants of the genus Erythroxylum.


Subject(s)
Astrocytes/cytology , Astrocytoma/physiopathology , Diterpenes/pharmacology , Erythroxylaceae/chemistry , Plant Extracts/pharmacology , Apoptosis/drug effects , Astrocytes/drug effects , Cell Line, Tumor , Cell Survival , DNA Fragmentation/drug effects , Humans , Models, Biological
11.
Mem Inst Oswaldo Cruz ; 102(4): 435-40, 2007 Jun.
Article in English | MEDLINE | ID: mdl-17612762

ABSTRACT

The infection by the hepatitis B virus (HBV) has different forms of evolution, ranging from self-limited infection to chronic hepatic disease. The objective of this study was to evaluate the influence of cytokine genetic polymorphisms in the disease evolution. The patients were divided into two groups, one with chronic HBV (n = 30), and the other with self-limited infection (n = 41). The genotyping for TNF (-308), TGFB1 (+869, +915), IL-10 (1082, -819, and -592), IL-6 (-174), and IFNG (+874) was accomplished by the PCR-SSP (polymerase chain reaction with sequence specific primers technique using the One Lambda kit. Although no statistically significant differences were found between the groups, the combination of TNF -308GG and IFNG +874TA was found in a lower frequency in chronic patients than in individuals with self-limited infection (26.7 versus 46.3%; P = 0.079; OR = 0.40; IC95% = 0.14-1.11). In chronic patients with histological alterations it was not observed the genotype TGFB1+869 C/C, against 24.4% in the self limited infection group (100 versus 75.6%; P = 0.096; OR = 7.67; IC95% = 0.42-141.63). Further studies in other populations, and evaluation of a greater number of individuals could contribute for a better understanding of the cytokine genetic polymorphism influence in HBV infection evolution.


Subject(s)
Cytokines/genetics , Hepatitis B, Chronic/genetics , Polymorphism, Genetic , Adult , Case-Control Studies , DNA Primers/genetics , Female , Genotype , Hepatitis B, Chronic/immunology , Humans , Male , Polymerase Chain Reaction/methods
12.
Mem. Inst. Oswaldo Cruz ; 102(4): 435-440, June 2007. tab
Article in English | LILACS | ID: lil-454793

ABSTRACT

The infection by the hepatitis B virus (HBV) has different forms of evolution, ranging from self-limited infection to chronic hepatic disease. The objective of this study was to evaluate the influence of cytokine genetic polymorphisms in the disease evolution. The patients were divided into two groups, one with chronic HBV (n = 30), and the other with self-limited infection (n = 41). The genotyping for TNF (-308), TGFB1 (+869, +915), IL-10 (1082, -819, and -592), IL-6 (-174), and IFNG (+874) was accomplished by the PCR-SSP (polymerase chain reaction with sequence specific primers technique using the One Lambda kit. Although no statistically significant differences were found between the groups, the combination of TNF -308GG and IFNG +874TA was found in a lower frequency in chronic patients than in individuals with self-limited infection (26.7 versus 46.3 percent; P = 0.079; OR = 0.40; IC95 percent = 0.14-1.11). In chronic patients with histological alterations it was not observed the genotype TGFB1+869 C/C, against 24.4 percent in the self limited infection group (100 versus 75.6 percent; P = 0.096; OR = 7.67; IC95 percent = 0.42-141.63). Further studies in other populations, and evaluation of a greater number of individuals could contribute for a better understanding of the cytokine genetic polymorphism influence in HBV infection evolution.


Subject(s)
Humans , Male , Female , Adult , Cytokines/genetics , DNA Primers/genetics , Hepatitis B, Chronic/immunology , Polymorphism, Genetic , Case-Control Studies , Genotype , Hepatitis B, Chronic/genetics , Polymerase Chain Reaction/methods
13.
J Biol Chem ; 277(26): 23927-33, 2002 Jun 28.
Article in English | MEDLINE | ID: mdl-11956199

ABSTRACT

Alpha-synuclein is the major component of Lewy bodies in patients with Parkinson's disease, and mutations in the alpha-synuclein gene are responsible for some familial forms of the disease. alpha-Synuclein is enriched in the presynapse, but its synaptic targets are unknown. Synphilin-1 associates in vivo with alpha-synuclein promoting the formation of intracellular inclusions. Additionally synphilin-1 has been found to be an intrinsic component of Lewy bodies in patients with Parkinson's disease. To understand the role of synphilin-1 in Parkinson's disease, we sought to define its localization and function in the brain. We now report that, like alpha-synuclein, synphilin-1 was enriched in neurons. In young rats, synphilin-1 was prominent in neuronal cell bodies but gradually migrated to neuropil during development. Immunoelectron microscopy of adult rat cerebral cortex demonstrated that synphilin-1 was highly enriched in presynaptic nerve terminals. Synphilin-1 co-immunoprecipitated with synaptic vesicles, indicating a strong association with these structures. In vitro binding experiments demonstrated that the N terminus of synphilin-1 robustly associated with synaptic vesicles and that this association was resistant to high salt washing but was abolished by inclusion of alpha-synuclein in the incubation medium. Our data indicated that synphilin-1 is a synaptic partner of alpha-synuclein, and it may mediate synaptic roles attributed to alpha-synuclein.


Subject(s)
Carrier Proteins/analysis , Nerve Tissue Proteins/analysis , Nerve Tissue Proteins/physiology , Presynaptic Terminals/chemistry , Synaptic Vesicles/chemistry , Animals , Carrier Proteins/physiology , Rats , Rats, Wistar , Synucleins , alpha-Synuclein
14.
Brain Res ; 929(2): 202-9, 2002 Mar 08.
Article in English | MEDLINE | ID: mdl-11864625

ABSTRACT

D-Serine is an endogenous agonist of NMDA receptors that occurs in astrocytes in gray matter areas of the brain. D-Serine is synthesized from L-serine by the activity of a glial enriched serine racemase, but little is known on the properties of D-serine transport and factors regulating its synaptic concentration. In the present report we characterize the transport of D-serine in astrocytes. In primary astrocyte cultures, D-serine uptake is dependent on sodium ions and exhibits both low affinity and low specificity for D-serine. The kinetics of D-serine transport resembles that of ASCT type transporters as several small neutral amino acids strongly inhibit the uptake of D-serine. D-Serine fluxes are coupled to counter-movement of L-serine and to a less extent to other small neutral amino acids. Thus, addition of D-serine to cell cultures elicits robust efflux of intracellular L-serine. Conversely, physiological concentrations of L-serine induce efflux of preloaded D-serine from astrocytes. L-Serine was more effective than kainate, which have been previously shown to induce D-serine release from astrocytes upon stimulation of non-NMDA type of glutamate receptors. The features of D-serine transport we describe reveal possible new mechanisms controlling the synaptic concentration of D-serine.


Subject(s)
Astrocytes/metabolism , Excitatory Amino Acid Agonists/pharmacokinetics , Neurotransmitter Agents/pharmacokinetics , Serine/pharmacokinetics , Amino Acids, Neutral/pharmacology , Animals , Binding, Competitive , Biological Transport/drug effects , Carrier Proteins/metabolism , Cells, Cultured , Excitatory Amino Acid Agonists/pharmacology , Intracellular Membranes/metabolism , Ions , Kinetics , Neurotransmitter Agents/chemistry , Neurotransmitter Agents/pharmacology , Rats , Rats, Wistar , Serine/chemistry , Serine/pharmacology , Sodium/metabolism , Stereoisomerism
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