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1.
Int J Mol Sci ; 25(3)2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38339069

RESUMO

Parkinson's disease (PD) is characterized by substantial phenotypic heterogeneity that limits the disease prognosis and patient's counseling, and complicates the design of further clinical trials. There is an unmet need for the development and validation of biomarkers for the prediction of the disease course. In this study, we utilized flow cytometry and in vitro approaches on peripheral blood cells and isolated peripheral blood mononuclear cell (PBMC)-derived macrophages to characterize specific innate immune populations in PD patients versus healthy donors. We found a significantly lower percentage of B lymphocytes and monocyte populations in PD patients. Monocytes in PD patients were characterized by a higher CD40 expression and on-surface expression of the type I membrane glycoprotein sortilin, which showed a trend of negative correlation with the age of the patients. These results were further investigated in vitro on PBMC-derived macrophages, which, in PD patients, showed higher sortilin expression levels compared to cells from healthy donors. The treatment of PD-derived macrophages with oxLDL led to higher foam cell formation compared to healthy donors. In conclusion, our results support the hypothesis that surface sortilin expression levels on human peripheral monocytes may potentially be utilized as a marker of Parkinson's disease and may segregate the sporadic versus the genetically induced forms of the disease.


Assuntos
Doença de Parkinson , Humanos , Leucócitos Mononucleares/metabolismo , Proteínas Adaptadoras de Transporte Vesicular/genética , Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Biomarcadores/metabolismo
2.
Food Chem Toxicol ; 142: 111508, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32544564

RESUMO

Whey protein, a by-product of cheese industry, is harmful for the environment (i.e., surface and subterranean waters, soil) and, therefore, for humans due to its high polluting burden. Concomitantly, it has been reported that it is a mixture with potent antioxidant action since it is rich in cysteine residues, which are necessary for glutathione synthesis in vivo. On this basis, this study intended to examine the role of whey protein on the intensification of tissue antioxidant arsenal. To this end, a dose of sheep/goat whey protein equal to 1 g/kg of body weight/day dissolved in drinking water was administered to rats for 28 consecutive days. According to our findings, whey protein improved the antioxidant profile of liver, small intestine, lung and muscle whereas it did not affect the redox state of kidney. Our results were based on the alterations found in the protein expression of glutamate cysteine ligase, catalase and superoxide dismutase-1 measured in all tissues and the activity of glutathione S-transferase evaluated in muscle. Although tissue-specific, it is obvious that the action of whey protein is biologically beneficial and could serve as a biofunctional constituent for foods able to improve redox profile when administered against redox-related diseases.


Assuntos
Antioxidantes/farmacologia , Enzimas/metabolismo , Proteínas do Soro do Leite/farmacologia , Animais , Cabras , Masculino , Oxirredução , Ratos , Ratos Wistar , Ovinos
3.
Nat Commun ; 11(1): 1855, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-32296057

RESUMO

Gravity sensing provides a robust verticality signal for three-dimensional navigation. Head direction cells in the mammalian limbic system implement an allocentric neuronal compass. Here we show that head-direction cells in the rodent thalamus, retrosplenial cortex and cingulum fiber bundle are tuned to conjunctive combinations of azimuth and tilt, i.e. pitch or roll. Pitch and roll orientation tuning is anchored to gravity and independent of visual landmarks. When the head tilts, azimuth tuning is affixed to the head-horizontal plane, but also uses gravity to remain anchored to the allocentric bearings in the earth-horizontal plane. Collectively, these results demonstrate that a three-dimensional, gravity-based, neural compass is likely a ubiquitous property of mammalian species, including ground-dwelling animals.


Assuntos
Encéfalo/fisiologia , Gravitação , Animais , Encéfalo/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Percepção Espacial/fisiologia , Memória Espacial/fisiologia , Tálamo/metabolismo , Tálamo/fisiologia
4.
Anticancer Res ; 40(4): 2025-2032, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32234893

RESUMO

BACKGROUND/AIM: The winemaking procedure results in the generation of stems, a by-product that is harmful to the environment. Concomitantly, stems are rich in polyphenols and, hence, they are putatively beneficial for human health. MATERIALS AND METHODS: In this study, the grape stem extracts derived from three native Greek vine varieties, namely Mavrodaphne, Muscat and Rhoditis were examined for their chemical composition and antioxidant and antimutagenic properties using a battery of in vitro biomarkers. RESULTS: All extracts are rich in polyphenols. Moreover, they exhibit potent antioxidant and antimutagenic properties with the extract of Mavrodaphne being the strongest in reducing the DPPH• and O2 -• radicals and the Fe3+ and in protecting plasmid DNA from peroxyl radical-induced oxidative modification. CONCLUSION: Therefore, although they are serious pollutants, grape stems contain phytochemicals with important biological properties and can be used as (ingredients of) bio-functional foods to improve certain aspects of human health.


Assuntos
Antioxidantes/farmacologia , DNA/efeitos dos fármacos , Polifenóis/farmacologia , Vitis/química , DNA/metabolismo , Dano ao DNA/efeitos dos fármacos , Grécia , Humanos , Oxirredução , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Caules de Planta/química , Plasmídeos/efeitos dos fármacos , Plasmídeos/metabolismo , Polifenóis/química , Espécies Reativas de Oxigênio/metabolismo
5.
Environ Res ; 182: 109074, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31923849

RESUMO

Xenobiotic metabolism at menopause is an under-investigated topic, albeit women spend one-third of their life in the postmenopausal period. The present study examined the effect of menopause on the in vivo activities of CYP1A2, CYP2A6, xanthine oxidase (XO) and N-acetyltransferase-2 (NAT2) xenobiotic metabolizing enzymes. Enzyme activity was determined in 152 non-smoking volunteers following oral intake of a single dose of 200 mg caffeine and subsequent determination of caffeine metabolite ratios (CMRs) in a 6-h urine sample as follows: CYP1A2: (AFMU+1U+1X)/17U, CYP2A6: 17U/(17U + 17X), XO: 1U/(1U+1X) and NAT2: AFMU/(AFMU+1U+1X). CMRs among groups were analyzed using one-way ANOVA. Significantly lower CYP1A2 and higher CYP2A6 CMRs were observed in postmenopausal compared to premenopausal women and age-matched men. These changes could be attributed to menopause rather than chronological aging since an age-related effect was not observed in premenopausal women or men of any age group. XO CMRs were higher in postmenopausal women and men>50 compared to premenopausal women and men<50, respectively, suggesting an age-related increase in XO activity. No significant alterations were discerned in NAT2 CMRs, in either slow- or rapid-acetylators, indicating that menopause exerts minimal modulation of xenobiotics metabolized by this enzyme. This study provides evidence that the transition to menopause induces significant alterations in xenobiotic-metabolizing enzymes independent of chronological aging suggesting altered metabolism of pharmaceutical and environmental agents.


Assuntos
Arilamina N-Acetiltransferase , Menopausa , Xenobióticos , Arilamina N-Acetiltransferase/metabolismo , Cafeína , Estudos Transversais , Citocromo P-450 CYP1A2/metabolismo , Feminino , Humanos , Masculino , Xenobióticos/metabolismo
6.
Food Chem Toxicol ; 130: 32-43, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31082462

RESUMO

Crocus sativus L., a perennial plant grown mainly around the Mediterranean and Iran, has many medicinal properties including anti-inflammatory, anti-depressive and cancer preventing properties. Aqueous herbal extracts may affect the activity of Phase I and II enzymes involved in xenobiotic metabolism. The present study was designed to determine whether C. sativus infusion alters the activity of CYP1A2, CYP2A6, XO and NAT2 enzymes in humans. Thirty-four healthy volunteers consumed infusion prepared from C. sativus stigmata for six days. Enzyme phenotyping was assessed in saliva and urine using caffeine metabolite ratios as follows: CYP1A2: 17X/137Χ (saliva) and CYP1A2: (AFMU+1U+1X)/17U, CYP2A6: 17U/(17U + 17X), XO: 1U/(1U+1X) and NAT2: AFMU/(AFMU+1U+1X) (urine). Following C. sativus intake, CYP1A2 index was reduced by ∼13.7% in saliva (before: 0.51 ±â€¯0.22, after: 0.44 ±â€¯0.14; p = 0.002) and ∼6.0% in urine (before: 3.81 ±â€¯1.20, after: 3.58 ±â€¯0.92; p = 0.054). CYP1A2 index was significantly reduced only in males (saliva, before: 0.65 ±â€¯0.22, after: 0.51 ±â€¯0.16; p = 0.0001; urine, before: 4.53 ±â€¯1.19, after: 4.03 ±â€¯0.87; p = 0.017) suggesting sexual dimorphism in CYP1A2 inhibition. There was no effect of C. sativus intake on CYP2A6, XO or NAT2 indices. Short-term consumption of C. sativus infusion is unlikely to result in significant herb-drug interactions involving the enzymes studied, with the exception of potential herb-CYP1A2 substrate interaction in males.


Assuntos
Crocus/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Fígado/enzimologia , Adulto , Carotenoides/química , Feminino , Voluntários Saudáveis , Interações Ervas-Drogas , Humanos , Fígado/metabolismo , Masculino , Pessoa de Meia-Idade , Adulto Jovem
7.
J Surg Res ; 234: 325-333, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30527492

RESUMO

BACKGROUND: The use of surgical meshes in ventral hernia repair has significantly reduced hernia recurrence rates. However, when placed intraperitoneally prosthetic materials can trigger the development of peritoneal adhesions. The present experimental study evaluated the combined icodextrin 4% and dimetindene maleate treatment in preventing peritoneal adhesion formation to polypropylene and titanium-coated polypropylene meshes. MATERIALS AND METHODS: Sixty female white rabbits were divided into four groups. A 2 × 2 cm piece of mesh was fixed to intact peritoneum in all animals through a midline laparotomy. A lightweight polypropylene mesh was implanted in groups 1 and 2 and a titanium-coated polypropylene mesh in groups 3 and 4. Groups 2 and 4 were treated, intraoperatively, with intravenous dimetindene maleate (0.1 mg/kg) and intraperitoneal solution of icodextrin 4% (20 mL/kg) and for the next 6 d with dimetindene maleate intramuscularly. The observation period lasted 15 d. Adhesion scores, percentage of mesh affected surface, tissue hydroxyproline levels, and tissue histopathology were examined. RESULTS: All animals in group 1 and 57% of animals in group 3 presented postoperative adhesions. The combination of antiadhesives significantly reduced the extent and severity of adhesions as well as the hydroxyproline levels in groups 2 and 4 compared with groups 1 and 3. On microscopic evaluation, animals in group 1 exhibited higher inflammation scores compared with group 2, whereas animals in groups 2 and 4 had better mesotheliazation compared with groups 1 and 3. CONCLUSIONS: The combined administration of icodextrin 4% and dimetindene maleate reduces the extent and severity of adhesions and may be successfully used to prevent adhesion formation after mesh intraperitoneal placement.


Assuntos
Dimetideno/administração & dosagem , Icodextrina/administração & dosagem , Polipropilenos/efeitos adversos , Complicações Pós-Operatórias/prevenção & controle , Substâncias Protetoras/administração & dosagem , Telas Cirúrgicas/efeitos adversos , Aderências Teciduais/prevenção & controle , Animais , Dimetideno/uso terapêutico , Quimioterapia Combinada , Feminino , Icodextrina/uso terapêutico , Injeções Intramusculares , Injeções Intraperitoneais , Injeções Intravenosas , Complicações Pós-Operatórias/etiologia , Substâncias Protetoras/uso terapêutico , Coelhos , Distribuição Aleatória , Resultado do Tratamento
8.
Food Chem Toxicol ; 122: 38-48, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30266316

RESUMO

Sideritis scardica(S. scardica) is an endemic plant of the Balkan Peninsula traditionally used as herbal tea for inflammation and gastric disorders. Aqueous herbal extracts may affect the activity of Phase I and II enzymes involved in xenobiotic metabolism. The purpose of the present study was to determine whether S. scardica decoction alters the activity of CYP1A2, CYP2A6, XO, NAT2 and UGT1A1/1A6 enzymes in humans. Fourteen healthy subjects consumed S. scardica decoction for six days. Enzyme phenotyping was assessed in saliva and urine using caffeine and paracetamol metabolite ratios as follows: CYP1A2: 17X/137X (saliva) and (AFMU+1U+1X)/17U, CYP2A6: 17U/(17U + 17X), XO: 1U/(1U+1X), NAT2: AFMU/(AFMU+1U+1X) and UGT1A1/1A6: glucuronidated/total paracetamol (urine). After S. scardica intake, CYP1A2 index was reduced by ∼16% and ∼8% in saliva (before: 0.54 ±â€¯0.18, after: 0.46 ±â€¯0.09; p = 0.08) and urine (before: 3.59 ±â€¯0.52, after: 3.67 ±â€¯0.78; p = 0.12), respectively. CYP2A6 index was significantly reduced only in males (before: 0.76 ±â€¯0.08, after: 0.67 ±â€¯0.07; p = 0.004), suggesting sexual dimorphism in CYP2A6 inhibition. There was no effect of Sideritis scardica treatment on XO, NAT2 or UGT1A1/1A6 indices. Usual consumption of the aerial parts of S. scardica decoction is unlikely to result in herb-drug interactions involving the enzymes studied, with the exception of potential herb-CYP2A6 substrate interaction in males.


Assuntos
Arilamina N-Acetiltransferase/metabolismo , Citocromo P-450 CYP1A2/metabolismo , Citocromo P-450 CYP2A6/metabolismo , Exposição Dietética , Glucuronosiltransferase/metabolismo , Sideritis , Chás de Ervas , Xantina Oxidase/metabolismo , Xenobióticos/metabolismo , Acetaminofen/metabolismo , Adulto , Arilamina N-Acetiltransferase/urina , Cafeína/metabolismo , Citocromo P-450 CYP1A2/urina , Citocromo P-450 CYP2A6/urina , Feminino , Glucuronosiltransferase/urina , Voluntários Saudáveis , Interações Ervas-Drogas , Humanos , Masculino , Pessoa de Meia-Idade , Componentes Aéreos da Planta , Saliva/enzimologia , Especificidade por Substrato , Xantina Oxidase/urina , Adulto Jovem
9.
Acta Neurochir (Wien) ; 160(6): 1167-1174, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29696502

RESUMO

BACKGROUND: We aim to review the available literature on patients suffering from glioblastoma treated with tumor-treating fields (TTFields) plus radio chemotherapy or conventional radio chemotherapy alone, to compare the efficacy and safety of the two methods. METHODS: A systematic literature search was performed in PubMed, Cochrane library, and Scopus databases, in accordance with the PRISMA guidelines. Six studies met the inclusion criteria incorporating 1806 patients for the qualitative analysis and 1769 for the quantitative analysis. RESULTS: This study reveals increased median overall survival (weighted mean difference (WMD) 3.29 [95% confidence interval (CI) 2.37, 4.21]; p < 0.00001), survival at 1 year (odds ratio (OR) 1.81 [95% CI 1.41, 2.32]; p < 0.00001) and 2 years (OR 2.33 [95% CI 1.73, 3.14]; p < 0.00001), and median progression-free survival (WMD 2.35 [95% CI 1.76, 2.93]; p < 0.00001) along with progression-free survival at 6 months (WMD 6.86 [95% CI 5.91, 7.81]; p < 0.00001) for the patients treated with TTFields. Survival at 3 years was comparable between the two groups. TTFields were associated with fewer adverse events compared to chemotherapy along with similar incidence of skin irritation. CONCLUSIONS: TTFields are a safe and efficient novel treatment modality. More randomized controlled studies, with longer follow-up, are necessary to further assess the clinical outcomes of TTFields.


Assuntos
Neoplasias Encefálicas/terapia , Terapia por Estimulação Elétrica/métodos , Glioblastoma/terapia , Quimiorradioterapia/métodos , Terapia por Estimulação Elétrica/efeitos adversos , Humanos , Intervalo Livre de Progressão
10.
Biomed Chromatogr ; 31(9)2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28182284

RESUMO

Licarbazepine is the pharmacologically active metabolite of oxcarbazepine, a drug indicated for the treatment of partial seizures and bipolar disorders. Several HPLC methods have been developed thus far but there is lack of control for interferences from antipsychotic drugs. The aim of the present study was to develop a simple, low-cost and reliable HPLC-UV method for the determination of licarbazepine in human serum in the presence of co-administered antiepileptic, antipsychotic and commonly prescribed drugs. Sample preparation consisted of a single protein precipitation step with methanol. Separation lasted ~9 min on a reversed-phase C18 column using a mobile phase composed of 50 mm sodium-dihydrogen-phosphate-monohydrate/acetonitrile (70:30, v/v) delivered isocratically at 0.9 mL/min and 30°C. Wavelength was 210 nm and calibration curve was linear with r2 0.998 over the range 0.2-50.0 µg/mL. Coefficient of variation was <5.03% and bias <-4.92%. Recovery ranged from 99.49 to 104.52% and the limit of detection was 0.0182 µg/mL. No interferences from the matrix or from antiepileptic, antipsychotic and commonly prescribed drugs were observed. The method was applied to serum samples of patients under oxcarbazepine treatment and proved to be a useful tool for the therapeutic drug monitoring of licarbazepine during monotherapy or adjunctive treatment of seizures or affective disorders.


Assuntos
Anticonvulsivantes/sangue , Carbamazepina/análogos & derivados , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia de Fase Reversa/métodos , Carbamazepina/sangue , Monitoramento de Medicamentos/métodos , Epilepsia , Humanos , Limite de Detecção , Modelos Lineares , Oxcarbazepina , Reprodutibilidade dos Testes
11.
Food Chem Toxicol ; 100: 80-89, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28011360

RESUMO

Peppermint leaves are widely used for the symptomatic treatment of digestive disorders. Previous studies have shown significant effects of its natural products on human enzyme activity; however, there is no study available concerning the effects of peppermint tea on metabolizing enzymes in humans. Aim of the present study was to investigate the effect of peppermint tea on CYP1A2, CYP2A6, Xanthine Oxidase (XO), N-acetyltranferase-2 (NAT2) and UDP-glucuronosyltransferases-1A1/1A6 (UGT1A1/1A6) activities in healthy subjects. Four males and five females consumed peppermint tea (2 g of dry leaves/200 mL water, twice daily) for six days. CYP1A2, CYP2A6, XO, NAT2 and UGT1A1/1A6 activities were determined before and at the end of the study period, using the following caffeine and paracetamol metabolic ratios: CYP1A2: 17MX/137MX (saliva) and (AFMU+1MU+1MX)/17MU (urine); CYP2A6: 17MU/(17MU + 17MX), XO: 1MU/(1MU+1MX), NAT2, AFMU/(AFMU+1MU+1MX) and UGT1A1/1A6 glucuronidated/total paracetamol, all determined in urine. NAT2 metabolic ratio was significantly reduced following peppermint consumption (0.15 ± 0.13 vs 0.14 ± 0.13; p < 0.05). CYP1A2 urine and saliva indices were reduced, yet not significantly, following peppermint consumption (urine: 3.17 ± 1.08 vs 2.91 ± 0.76, saliva: 0.56 ± 0.12 vs 0.50 ± 0.12; p > 0.05). Peppermint had no influence on CYP2A6, XO and UGT1A1/1A6 indices. Daily ingestion of peppermint tea may alter pharmacokinetics of clinically administered drugs and promote cancer chemoprevention through NAT2 inhibition.


Assuntos
Arilamina N-Acetiltransferase/metabolismo , Citocromo P-450 CYP1A2/metabolismo , Citocromo P-450 CYP2A6/metabolismo , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Glucuronosiltransferase/metabolismo , Mentha piperita/química , Extratos Vegetais/farmacologia , Chá/química , Xantina Oxidase/metabolismo , Adulto , Cromatografia Líquida , Feminino , Voluntários Saudáveis , Humanos , Masculino , Espectrometria de Massas , Pessoa de Meia-Idade , Extratos Vegetais/química , Adulto Jovem
12.
Biomed Chromatogr ; 29(11): 1657-63, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25891161

RESUMO

CYP1A2 is important for metabolizing various clinically used drugs. Phenotyping of CYP1A2 may prove helpful for drug individualization therapy. Several HPLC methods have been developed for quantification of caffeine metabolites in plasma and urine. Aim of the present study was to develop a valid and simple HPLC method for evaluating CYP1A2 activity during exposure in xenobiotics by the use of human saliva. Caffeine and paraxanthine were isolated from saliva by liquid-liquid extraction (chlorophorm/isopropanol 85/15v/v). Extracts were analyzed by reversed-phase HPLC on a C18 column with mobile phase 0.1% acetic acid/methanol/acetonitrile (80/20/2 v/v) and detected at 273nm. Caffeine and paraxanthine elution times were <13min with no interferences from impurities or caffeine metabolites. Detector response was linear (0.10-8.00µg/ml, R(2) >0.99), recovery was >93% and bias <4.47%. Intra- and inter-day precision was <5.14% (n=6). The limit of quantitation was 0.10µg/ml and the limit of detection was 0.018±0.002µg/mL for paraxanthine and 0.032±0.002µg/ml for caffeine. Paraxanthine/caffeine ratio of 34 healthy volunteers was significantly higher in smokers (p<0.001). Saliva paraxanthine/caffeine ratios and urine metabolite ratios were highly correlated (r=0.85, p<0.001). The method can be used for the monitoring of CYP1A2 activity in clinical practice and in studies relevant to exposure to environmental and pharmacological xenobiotics.


Assuntos
Cafeína/metabolismo , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia de Fase Reversa/métodos , Citocromo P-450 CYP1A2/metabolismo , Saliva/metabolismo , Calibragem , Humanos , Limite de Detecção , Fenótipo , Padrões de Referência , Reprodutibilidade dos Testes , Espectrofotometria Ultravioleta
13.
J Chromatogr Sci ; 52(7): 590-5, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23800772

RESUMO

Methotrexate (MTX) is a dihydrofolate reductase inhibitor that is used for the treatment of tumors and autoimmune diseases. Several automated binding assays are used in clinical practice and numerous chromatographic methods have been developed toward higher specificity and sensitivity. In the present study, phenyl cartridges were used for the solid-phase extraction (SPE) of MTX from human serum samples; subsequently, extracts were analyzed by reversed-phase high-performance liquid chromatography. Isocratic separation was implemented on a Kromasil-C18 column with a mobile phase consisting of 50 mM sodium acetate buffer (pH 3.6)-acetonitrile (89:11, v/v) and ultraviolet detection at 307 nm. MTX eluted in less than 12 min with no interference from impurities or 24 examined drugs. Detector response was linear in the range of 0.025-5.00 µΜ (coefficient of correlation > 0.99). Recovery from the serum was 93.1-98.2% and bias was < 8.3%. Intra-day and inter-day precision were <7.8 and 12.6%, respectively (n = 6). The limit of quantitation was 0.01 µM and the limit of detection was 0.003 µΜ. The method was validated by using serum samples from osteosarcoma patients treated with high-dose MTX (8-12 g/m(2)). In conclusion, the combined use of a phenyl-functionalized sorbent for SPE and a Kromasil-C18 column, and specific detection at 307 nm, assured a selective, fast, robust and cost-effective method for the monitoring of MTX in osteosarcoma patients under high-dose MTX treatment, thus contributing to more efficient treatment.


Assuntos
Antineoplásicos/sangue , Cromatografia Líquida de Alta Pressão/métodos , Monitoramento de Medicamentos/métodos , Metotrexato/sangue , Osteossarcoma/tratamento farmacológico , Adulto , Antineoplásicos/química , Antineoplásicos/farmacocinética , Antineoplásicos/uso terapêutico , Feminino , Humanos , Limite de Detecção , Modelos Lineares , Masculino , Metotrexato/química , Metotrexato/farmacocinética , Metotrexato/uso terapêutico , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Adulto Jovem
14.
Int J Neurosci ; 121(6): 289-304, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21348800

RESUMO

Since it was first observed, synaptic plasticity has been considered as the experimental paradigm most likely to provide us with an understanding of how information is stored in the vertebrate brain. Various types have been demonstrated over these past 45 years, most notably long-term potentiation and long-term depression, and their established characteristics as well as their induction and consolidation requirements are highly indicative of this plasticity being the substrate for skills acquisition and mnemonic engraving. The molecular, biochemical, and structural models that have been proposed in the past, although most accommodate some aspect of synaptic plasticity observations, admittedly cannot offer a universally functional connection between all the phenomena that surround and result in the different modifications of synaptic efficacy. As a result, there are a number of persisting questions. In an attempt toward synthesis, we reviewed the most important studies in the field and believe that we can now propose a unifying Model for synaptic plasticity that can accommodate the experimental evidence and reconcile most of the contradictions. Moreover, from this model emerge potential answers to several unyielding questions, namely, accounting for the induction and expression of long-term depression, identifying the plasticity switch, offering a possible explanation for the sliding modification threshold, and proposing a new mechanism for synaptic tagging.


Assuntos
Modelos Neurológicos , Plasticidade Neuronal/fisiologia , Sinapses/fisiologia , Transmissão Sináptica/fisiologia , Animais , Sinalização do Cálcio/fisiologia , Espinhas Dendríticas/metabolismo , Espinhas Dendríticas/fisiologia , Humanos , Potenciação de Longa Duração/fisiologia , Depressão Sináptica de Longo Prazo/fisiologia
15.
Brain Res ; 948(1-2): 117-21, 2002 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-12383962

RESUMO

Extracellular and intracellular recordings were made from slices taken from the dorsal (DH) and ventral (VH) part of rat hippocampus. Using paired-pulse stimulation of Schaffer collaterals, at different interpulse intervals (IPIs), and records of the population spike (PS) we found that the strength and duration of paired-pulse inhibition was much weaker in VH compared to DH slices: at the IPI of 10 ms the decrease of PS in VH (40%) was significantly smaller compared to that in DH slices (76%), while at 20 ms the decrease of PS in DH slices (60%) corresponded to facilitation in VH slices. Moreover, the amplitude and duration of intracellularly recorded fast inhibitory postsynaptic potentials (fast-IPSPs) were found significantly smaller in VH (5.2+/-0.6 mV, 54.8+/-5.8 ms) than in DH (11.2+/-1.1 mV, 105+/-10 ms) neurons. The smaller and shorter fast-IPSP recorded in VH neurons may at least in part explain the results in paired-pulse inhibition. The demonstrated weaker inhibition may underlie the higher propensity of the ventral hippocampus for epileptiform activity.


Assuntos
Hipocampo/fisiologia , Inibição Neural/fisiologia , Sinapses/fisiologia , Transmissão Sináptica/fisiologia , Animais , Estimulação Elétrica , Potenciais Evocados/efeitos dos fármacos , Potenciais Evocados/fisiologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Antagonistas GABAérgicos/farmacologia , Antagonistas de Receptores de GABA-B , Hipocampo/citologia , Hipocampo/efeitos dos fármacos , Técnicas In Vitro , Masculino , Inibição Neural/efeitos dos fármacos , Especificidade de Órgãos/fisiologia , Células Piramidais/efeitos dos fármacos , Células Piramidais/fisiologia , Ratos , Ratos Wistar , Sinapses/efeitos dos fármacos , Transmissão Sináptica/efeitos dos fármacos
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