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1.
J Eur Acad Dermatol Venereol ; 36 Suppl 1: 66-69, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34855253

RESUMO

A 78-year-old woman was referred to our skin cancer centre with three previous incomplete resections in the left cavum conchae of a deep-infiltrating locally advanced, but still asymptomatic basal cell carcinoma (BCC). The patient noted furthermore two rapidly growing exophytic lesions in the left preauricular and cervical area in the last weeks. The clinical and histological distinction of locally advanced from metastatic cutaneous squamous cell carcinoma (CSCC) lesions was challenging. Imaging analysis with CT scans showed, however, an involvement of the parotid gland as well as multiple small lymph node metastases. The interdisciplinary tumour board decision at our institution recommended a systemic treatment with the PD1-antibody cemiplimab. After 13 cycles with cemiplimab at a dose of 350 mg intravenously every 3-weeks, the patient showed a complete response of the two CSCC lesions with histological confirmation. However, the BCC of the left ear appeared to be unchanged and still asymptomatic. The interdisciplinary tumour board considered this tumour to be no candidate for a curative resection or irradiation. Therefore, the patient was exposed to the hedgehog inhibitor sonidegib with a conventional dose of 200 mg orally per day. After 3 months of treatment, the tumour showed a markable regression and a complete response was confirmed by 3-punch biopsies from this preoperated lesion. Both cemiplimab and sonidegib were excellently tolerated with almost no adverse events apart from a mild fatigue (CTC grade 1) over the first 3 weeks of the cemiplimab therapy. There were no laboratory abnormalities found.


Assuntos
Carcinoma Basocelular , Carcinoma de Células Escamosas , Neoplasias Cutâneas , Idoso , Anticorpos Monoclonais Humanizados , Compostos de Bifenilo , Carcinoma Basocelular/tratamento farmacológico , Carcinoma de Células Escamosas/tratamento farmacológico , Células Epiteliais , Feminino , Proteínas Hedgehog , Humanos , Piridinas , Neoplasias Cutâneas/tratamento farmacológico
2.
Mol Cell Pediatr ; 11(1): 6, 2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-39085734

RESUMO

BACKGROUND: As an indigestible component of human breast milk, Human Milk Oligosaccharides (HMOs) play an important role as a substrate for the establishing microbiome of the newborn. They have further been shown to have beneficial effects on the immune system, lung and brain development. For preterm infants HMO composition of human breast milk may be of particular relevance since the establishment of a healthy microbiome is challenged by multiple disruptive factors associated with preterm birth, such as cesarean section, hospital environment and perinatal antibiotic exposure. In a previous study it has been proposed that maternal probiotic supplementation during late stages of pregnancy may change the HMO composition in human milk. However, there is currently no study on pregnancies which are threatened to preterm birth. Furthermore, HMO composition has not been investigated in association with clinically relevant outcomes of vulnerable infants including inflammation-mediated diseases such as sepsis, necrotizing enterocolitis (NEC) or chronic lung disease. MAIN BODY: A randomized controlled intervention study (PROMO = probiotics for human milk oligosaccharides) has been designed to analyze changes in HMO composition of human breast milk after supplementation of probiotics (Lactobacillus acidophilus, Bifidobacterium lactis and Bifidobacterium infantis) in pregnancies at risk for preterm birth. The primary endpoint is HMO composition of 3-fucosyllactose and 3'-sialyllactose in expressed breast milk. We estimate that probiotic intervention will increase these two HMO levels by 50% according to the standardized mean difference between treatment and control groups. As secondary outcomes we will measure preterm infants' clinical outcomes (preterm birth, sepsis, weight gain growth, gastrointestinal complications) and effects on microbiome composition in the rectovaginal tract of mothers at delivery and in the gut of term and preterm infants by sequencing at high genomic resolution. Therefore, we will longitudinally collect bio samples in the first 4 weeks after birth as well as in follow-up investigations at 3 months, one year, and five years of age. CONCLUSIONS: We estimate that probiotic intervention will increase these two HMO levels by 50% according to the standardized mean difference between treatment and control groups. The PROMO study will gain insight into the microbiome-HMO interaction at the fetomaternal interface and its consequences for duration of pregnancy and outcome of infants.

3.
Langmuir ; 28(40): 14395-404, 2012 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-22954621

RESUMO

In the absence of stabilizers in the reaction medium, the nonaqueous synthesis of metal oxide nanoparticles usually results in agglomerated products. Stabilization is however often possible in a postsynthetic treatment, involving the addition of organic ligands that coordinate to the nanoparticle surface. The ligands are commonly expected to chemisorb via functional groups; however, we have recently shown that also weakly and unspecifically interacting ligands can lead to stabilization. Here, we present detailed investigations on the stabilization, comparing the binding of weakly coordinating ligands to a system with strongly and selectively binding stabilizers and additionally exploring the effect of ligand chain length. Although in all cases stabilization and disintegration of agglomerates to the primary particle level are achieved, strong differences are observed with respect to the processes at the particle surface. Moreover, these processes are shown to be more complex than simple ligand adsorption and need to be understood for proper design and choice of stabilizers.


Assuntos
Nanopartículas/química , Compostos de Estanho/química , Compostos de Estanho/síntese química , Zircônio/química , Adsorção , Interações Hidrofóbicas e Hidrofílicas , Ligantes , Compostos Orgânicos/química , Propriedades de Superfície
4.
Struct Dyn ; 9(6): 064101, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36411869

RESUMO

The unprecedented intensity of x-ray free-electron laser sources has enabled single-particle x-ray diffraction imaging (SPI) of various biological specimens in both two-dimensional projection and three dimensions (3D). The potential of studying protein dynamics in their native conditions, without crystallization or chemical staining, has encouraged researchers to aim for increasingly higher resolutions with this technique. The currently achievable resolution of SPI is limited to the sub-10 nanometer range, mainly due to background effects, such as instrumental noise and parasitic scattering from the carrier gas used for sample delivery. Recent theoretical studies have quantified the effects of x-ray pulse parameters, as well as the required number of diffraction patterns to achieve a certain resolution, in a 3D reconstruction, although the effects of detector noise and the random particle orientation in each diffraction snapshot were not taken into account. In this work, we show these shortcomings and address limitations on achievable image resolution imposed by the adaptive gain integrating pixel detector noise.

5.
Phys Rev E ; 96(4-1): 043207, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29347579

RESUMO

We present a theory of electrostatic fluctuations in two-component plasmas where electrons and ions are described by Maxwellian distribution functions at unequal temperatures. Based on the exact solution of the Landau kinetic equation, that includes electron-electron, electron-ion, and ion-ion collision integrals, the dynamic form factor, S(k[over ⃗],ω), is derived for weakly coupled plasmas. The collective plasma responses at ion-acoustic, Langmuir, and entropy mode resonances are described for arbitrary wave numbers and frequencies in the entire range of plasma collisionality. The collisionless limit of S(k[over ⃗],ω) and the strong-collision result based on the fluctuation-dissipation theorem and classical transport at T_{e}=T_{i} are recovered and discussed. Results of several Thomson scattering experiments in the broad range of plasma parameters are described and discussed by means of our theory for S(k[over ⃗],ω).

6.
Neurology ; 52(8): 1577-82, 1999 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-10331681

RESUMO

OBJECTIVE: To determine whether memory scores after second intracarotid amobarbital procedure (IAP) injections are affected by the time between the first and second injections. METHODS: Sixty-two patients received their second IAP injection on the day after the first injection. Forty-three other patients received the second injection on the same day as the first injection. Both groups underwent similar IAP protocols and memory assessments, except for the timing of the second injection. RESULTS: The second IAP memory scores in the two-day group were significantly higher (p < 0.05) than those in the one-day group. Timing of second injection was a significant correlate of second memory scores, but amobarbital dosage, first IAP memory score, and pre-IAP measures of memory and intelligence were not significant correlates. CONCLUSION: One-day and two-day IAP protocols do not result in similar memory scores after the second injection. Nineteen percent of a subset of patients in the one-day protocol were misclassified, in terms of IAP memory ratings, because of the deleterious effect of having both injections on the same day. It is recommended that correction scores be considered, for some patients who receive two IAP injections on one day, to approximate what the second IAP memory score would have been had the second injection occurred on a second day.


Assuntos
Amobarbital , Anestésicos Intravenosos , Epilepsia/psicologia , Memória/fisiologia , Testes Neuropsicológicos , Adolescente , Adulto , Feminino , Humanos , Masculino , Memória/efeitos dos fármacos , Fatores de Tempo
7.
J Thorac Cardiovasc Surg ; 104(5): 1405-9, 1992 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-1434723

RESUMO

Cardiopulmonary bypass frequently causes new postoperative neuropsychologic deficits. To assess whether these deficits could be predicted or limited, we monitored 29 patients receiving bypass intraoperatively with an on-line computerized electroencephalograph. We hypothesized that the 15 patients whose cerebral perfusion pressure was adjusted on the basis of this electroencephalographic data would have fewer postoperative deficits than the 14 patients whose pressure was monitored on the basis of systemic pressure. The results showed that new postoperative cognitive deficits in both groups were less prevalent than in previous studies, but there was not a significant difference in outcomes between the two groups. The intraoperative electroencephalographic records correlated with surgical, but not neuropsychologic, outcome. It is concluded that careful attention to intraoperative cerebral perfusion pressure may decrease the prevalence of postoperative neuropsychologic complications, but that the use of a computerized electroencephalograph does not necessarily contribute to an improved outcome.


Assuntos
Ponte Cardiopulmonar/efeitos adversos , Cognição , Eletroencefalografia , Pressão Intracraniana , Adulto , Idoso , Idoso de 80 Anos ou mais , Computadores , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Monitorização Intraoperatória/métodos , Período Pós-Operatório
8.
Neurogastroenterol Motil ; 12(4): 343-52, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10886676

RESUMO

There is evidence suggesting that neuropeptide Y (NPY) as well as corticotropin-releasing factor (CRF) in the paraventricular nucleus of the hypothalamus (PVN) are involved in the CNS regulation of gastrointestinal (GI) function. We studied the effects of NPY or Y1-and Y2-receptor agonists microinjected into the PVN on colonic transit. Microinjection of NPY into the PVN at doses of 0.15-1.5 microg decreased the colonic transit time of conscious rats up to 49%. Pretreatment with the peripherally acting cholinergic antagonist atropine methyl nitrate (0.1 mg kg-1 i.p.) blocked the NPY into PVN-induced effect on colonic motor function.The agonist of the Y1-receptor, NPY(Leu31, Pro34), as well as the Y2-receptor agonist, NPY(13-36), dose-dependently decreased colonic transit time when microinjected into the PVN (0.05, 0.15 and 0.5 microg). However, the Y1-receptor agonist was more effective. Intracerebroventricular (ICV) application of the CRF-receptor antagonist, alpha-helical-CRF9-41 (50 microg/rat), blocked the NPY effect in the PVN on colonic motor function. In conclusion, stimulation of colonic transit by NPY acting in the PVN was observed. The PVN is more sensitive to agonists acting on the Y1- than on the Y2-receptor to mediate stimulation of propulsive colonic motility. The effect of NPY in the PVN on colonic motor function depends on central CRF and peripheral cholinergic pathways.


Assuntos
Colo/fisiologia , Hormônio Liberador da Corticotropina/fisiologia , Trânsito Gastrointestinal/fisiologia , Neuropeptídeo Y/fisiologia , Núcleo Hipotalâmico Paraventricular/metabolismo , Receptores Colinérgicos/fisiologia , Animais , Antagonistas Colinérgicos/farmacologia , Hormônio Liberador da Corticotropina/antagonistas & inibidores , Injeções Intraventriculares , Masculino , Microinjeções , Neuropeptídeo Y/metabolismo , Neuropeptídeo Y/farmacologia , Ratos , Ratos Sprague-Dawley , Receptores Colinérgicos/efeitos dos fármacos , Receptores de Neuropeptídeo Y/agonistas
9.
Brain Res ; 913(1): 10-7, 2001 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-11532242

RESUMO

It is well established that autonomic control of gastrointestinal function is modulated by central autonomic neurotransmission. In this context it has been shown that gastrointestinal motility and secretion can be modulated by exogenous neuropeptides microinjected into the paraventricular nucleus of the hypothalamus (PVN). Furthermore, there is considerable evidence suggesting that neurons projecting from the arcuate nucleus (Arc) to the PVN may be the source of endogenous neuropeptide release in the PVN. This poses the question whether stimulation of neurons in the arcuate nucleus, e.g. by an excitatory amino acid, alters gastrointestinal function. In the present study, we investigated the effect of an excitatory amino acid, kainate, microinjected into the arcuate nucleus on gastric acid secretion in urethane-anesthetized rats. Kainate (140 pmol/rat) bilaterally microinjected into the Arc induced an significant inhibition of pentagastrin (PG) stimulated (16 mg/kg per h) gastric acid secretion throughout an observation period of 120 min after microinjection. Microinjection of kainate into hypothalamic areas outside the arcuate nucleus did not modify gastric secretion. Bilateral cervical vagotomy blocked the effect of kainate injected into the Arc on PG-stimulated gastric acid secretion. These data show that gastric secretory function can be modulated by stimulation of neuronal activity in the Arc via efferent vagal pathways. The results suggest that the arcuate nucleus is a forebrain area involved in the CNS regulation of gastrointestinal function.


Assuntos
Núcleo Arqueado do Hipotálamo/metabolismo , Vias Eferentes/metabolismo , Ácido Gástrico/metabolismo , Bulbo/metabolismo , Inibição Neural/fisiologia , Núcleo Hipotalâmico Paraventricular/metabolismo , Nervo Vago/metabolismo , Anestésicos Intravenosos/farmacologia , Animais , Núcleo Arqueado do Hipotálamo/citologia , Núcleo Arqueado do Hipotálamo/efeitos dos fármacos , Vias Eferentes/citologia , Vias Eferentes/efeitos dos fármacos , Agonistas de Aminoácidos Excitatórios/farmacologia , Mucosa Gástrica/efeitos dos fármacos , Mucosa Gástrica/inervação , Mucosa Gástrica/metabolismo , Ácido Glutâmico/metabolismo , Ácido Caínico/farmacologia , Masculino , Bulbo/citologia , Inibição Neural/efeitos dos fármacos , Núcleo Hipotalâmico Paraventricular/citologia , Núcleo Hipotalâmico Paraventricular/efeitos dos fármacos , Pentagastrina/farmacologia , Ratos , Ratos Sprague-Dawley , Receptores de Ácido Caínico/efeitos dos fármacos , Receptores de Ácido Caínico/metabolismo , Fatores de Tempo , Uretana/farmacologia , Vagotomia , Nervo Vago/citologia , Nervo Vago/efeitos dos fármacos
10.
Artigo em Inglês | MEDLINE | ID: mdl-7682724

RESUMO

1. In vivo pulse voltammetry and apomorphine induced circling behaviour were used to study the effect of antiparkinsonian drugs and neurotoxins on striatal, extraneuronal dihydroxyphenylacetic acid (DOPAC) and 5-hydroxyindoleacetic acid (5-HIAA) concentrations which are a measure of dopamine (DA) release/DA metabolism and serotonin (5-HT) release, respectively. 2. The DA precursor dihydroxyphenylalanine (DOPA, i.p.) increased extraneuronal DOPAC and reduced 5-HIAA levels whereas the opposite effect was induced by the 5-HT precursor 5-hydroxytryptophan (5-HTP, i.p.). Tryptophan, i.p., decreased the extraneuronal DOPAC levels without significant effect on 5-HT release. 3. The monoamine oxidase (MAO) inhibitors pargyline, i.p., and deprenyl, i.p., as well as the DA agonist apomorphine, i.p., decreased the catechol signal. The DA antagonist haloperidol, i.p., increased extraneuronal DOPAC. 4. In longterm studies unilateral application of the neurotoxins 6-hydroxydopamine (6-OHDA), 1-methyl-4-phenyl-1,2,3,6-tetra-hydroxypyridine (MPTP), and 1-methyl-4-phenylpyridinium cation (MPP+) into the substantia nigra pars compacta abolished the DOPAC signal in the striatum at the lesioned side. This effect can be partially or fully restored by DOPA depending on the time elapsed after neurotoxin administration. 5. In accordance with the voltammetric recorded unilateral lesion of the dopaminergic system the apomorphine stimulated circling behaviour was significantly enhanced in MPTP and MPP+ treated rats as compared with controls. 6. The results obtained indicate that antiparkisonian drugs and neurotoxins besides their effect on total catecholamine and 5-HT concentrations change specifically the extraneuronal levels of the transmitter (metabolites). Moreover the results suggest that neurotoxin-treated rats can be used as a model to study Parkinson-like effects with regard to the pathogenesis and treatment of this disease.


Assuntos
Monoaminas Biogênicas/metabolismo , Doença de Parkinson Secundária/metabolismo , 1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina/análogos & derivados , Ácido 3,4-Di-Hidroxifenilacético/metabolismo , 5-Hidroxitriptofano/farmacologia , Animais , Apomorfina/farmacologia , Dopamina/metabolismo , Dopaminérgicos/farmacologia , Antagonistas de Dopamina , Ácido Hidroxi-Indolacético/metabolismo , Levodopa/farmacologia , Masculino , Inibidores da Monoaminoxidase/farmacologia , Doença de Parkinson Secundária/induzido quimicamente , Ratos , Ratos Wistar , Comportamento Estereotipado/efeitos dos fármacos , Triptofano/farmacologia
11.
Cortex ; 33(2): 385-8, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9220268

RESUMO

Cerebral malaria is a common disease, but there have not been any reports or investigations of long-term neurological or neuropsychological outcome. We present a case in which severe deficits in delayed memory and naming ability are observed 10 years after the patient contracted cerebral malaria. Neuropsychological testing and medical imaging are both consistent with temporal lobe/hippocampal dysfunction, which corroborates earlier animal research that cerebral malaria is particularly likely to lead to interrupted blood circulation in this area.


Assuntos
Dano Encefálico Crônico/diagnóstico , Malária Cerebral/diagnóstico , Malária Falciparum/diagnóstico , Retenção Psicológica/fisiologia , Adulto , Dano Encefálico Crônico/fisiopatologia , Dano Encefálico Crônico/psicologia , Mapeamento Encefálico , Hipocampo/fisiopatologia , Humanos , Malária Cerebral/fisiopatologia , Malária Cerebral/psicologia , Malária Falciparum/fisiopatologia , Malária Falciparum/psicologia , Masculino , Memória de Curto Prazo/fisiologia , Testes Neuropsicológicos , Aprendizagem por Associação de Pares/fisiologia , Lobo Temporal/fisiopatologia
12.
J Neural Transm Suppl ; 46: 107-15, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-8821046

RESUMO

The action of the amantadine derivative memantine on the dopamine metabolism in the striatum and the n. accumbens of the rat was studied in vivo with different voltammetrical techniques. It was shown by differential pulse voltammetry that memantine enhanced extracellular levels of dopamine (DA) in the striatum of the anaesthetized rat, whereas an increase of 3,4 dihydroxyphenylacetic acid (DOPAC) could be observed only under freely moving conditions using square wave voltammetry. Under chloral hydrate anaesthesia the effect of memantine on extracellular DOPAC levels in the striatum and the n. accumbens was compared with MK-801, a well-known non-competitive NMDA-antagonist. Memantine did not affect striatal DOPAC concentrations under these conditions whereas MK-801 reduced the DOPAC signal. In the n. accumbens memantine enhanced the levels of extracellular DOPAC, while after MK-801 the signal was only slightly different from control. These findings suggest that in addition to its NMDA receptor antagonism, memantine affects dopaminergic transmission also by other mechanisms.


Assuntos
Antiparkinsonianos/farmacologia , Corpo Estriado/efeitos dos fármacos , Dopamina/metabolismo , Memantina/farmacologia , Núcleo Accumbens/efeitos dos fármacos , Ácido 3,4-Di-Hidroxifenilacético/metabolismo , Animais , Corpo Estriado/metabolismo , Maleato de Dizocilpina/farmacologia , Eletroquímica , Masculino , Núcleo Accumbens/metabolismo , Ratos , Ratos Wistar
13.
J Neural Transm Suppl ; 46: 275-81, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-8821064

RESUMO

In vivo voltammetry with carbon fibre electrodes was used to study the effects of highly halogenated tetrahydro-beta-carbolines on the striatal dopamine (DA) metabolism of the rat. As representatives of chloral-derived heterocycles, "TaClo" (1-trichloro-1,2,3,4-tetrahydro-beta-carboline) and its N-methylated derivative. "N-methyl-TaClo", were investigated. After intranigral injection of 10 micrograms TaClo, the DA activity in the ipsilateral striatum was reduced compared with the intact side. Application of N-methyl-TaClo (10 micrograms) resulted in a nearly total reduction of the DOPAC signal. Furthermore, also "TaBro" (1-tribromomethyl-1,2,3,4-tetrahydro-beta-carboline), the bromal-derived analogue of TaClo, was tested. The impairment of the DA metabolism in rats achieved with 10 micrograms TaBro was found to be between that observed after application of TaClo and N-methyl-TaClo, respectively. The results demonstrate the toxic potential of chloral- and bromal-derived beta-carbolines towards dopaminergic neurons.


Assuntos
Carbolinas/toxicidade , Corpo Estriado/efeitos dos fármacos , Dopamina/metabolismo , Neurotoxinas/toxicidade , Substância Negra/efeitos dos fármacos , Ácido 3,4-Di-Hidroxifenilacético/metabolismo , Animais , Corpo Estriado/metabolismo , Eletroquímica , Levodopa/metabolismo , Masculino , Ratos , Ratos Wistar , Sensibilidade e Especificidade , Substância Negra/metabolismo
14.
J Neural Transm Suppl ; 46: 175-82, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-8821053

RESUMO

The substantia nigra of parkinsonian brains is reported to contain increased amounts of iron as compared with age-matched controls. Since iron might be cytotoxic via radical mechanisms, we analyzed the effect of intranigral iron infusion on the dopaminergic activity in the striatum of the rat. The striatal dopamine metabolism of the rat was followed 1, 3, and 6 weeks after unilateral intranigral iron (III) (1.5 micrograms) application. A progressive decrease of extraneuronal 3,4-dihydroxyphenylacetic acid (DOPAC) levels was observed in the ipsilateral striatum by means of in vivo pulse voltammetry. The significant reduction of the DOPAC signal could be attenuated by pretreatment of the animals with the lazaroid U-74389G, applied ip 20 minutes before unilateral intranigral iron application. Our data indicate that a single iron application into the substantia nigra leads to a progressive loss of dopaminergic activity in the striatum, also observed in Parkinson patients. Furthermore, the Lazaroid U-74389G seems to be beneficial in this model of Parkinson's disease.


Assuntos
Antioxidantes/farmacologia , Corpo Estriado/efeitos dos fármacos , Dopamina/metabolismo , Ferro/farmacologia , Fármacos Neuroprotetores/farmacologia , Pregnatrienos/farmacologia , Ácido 3,4-Di-Hidroxifenilacético/metabolismo , Animais , Corpo Estriado/metabolismo , Injeções , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Microeletrodos , Degeneração Neural/efeitos dos fármacos , Doença de Parkinson Secundária/induzido quimicamente , Doença de Parkinson Secundária/metabolismo , Ratos , Ratos Wistar , Substância Negra/efeitos dos fármacos , Substância Negra/metabolismo
15.
J Chromatogr A ; 795(2): 371-6, 1998 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-9528105

RESUMO

The accuracy and precision of solid-phase microextraction (SPME) were validated in an inter-laboratory study including ten laboratories for the analysis of triazine herbicides and their metabolites at ng/l level in aqueous samples. The SPME conditions were optimised in order to obtain maximum sensitivity. Especially, salt addition and choice of the SPME fibre coated with Carbowax-divinylbenzene increased the sensitivity. The average detection limits were in the range from 4 to 24 ng/l for the triazine herbicides, and 20 and 40 ng/l for desisopropylatrazine and desethylatrazine, respectively. The average r2 values of the calibration curves were above 0.99 for all of the analytes. The statistical data treatment was performed in accordance with the International Standardisation Organisation (ISO) standard 5725. Relative repeatability standard deviations between 6 and 14% and relative reproducibility standard deviations between 10 and 17% were found. The determined concentrations of the reference sample compared well to the "true" values, thus proving the good accuracy of the method. It is concluded that SPME is a reliable technique for the quantitative analysis of water samples containing triazine herbicides in concentrations around the European limit of 100 ng/l for individual pesticides in drinking water.


Assuntos
Herbicidas/análise , Herbicidas/normas , Resíduos de Praguicidas/análise , Triazinas , Abastecimento de Água/análise , Calibragem , Padrões de Referência , Reprodutibilidade dos Testes
16.
Ultrasound Med Biol ; 25(6): 901-4, 1999 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10461717

RESUMO

In recent studies, we have found a marked increase in substantia nigra (SN) echogenicity in patients with Parkinson's disease (PD) using transcranial ultrasound. Because a substantial body of evidence has accumulated indicating a selective elevation of iron in the SN from patients with PD, we set out to test the hypothesis that trace metals like iron could lead to the observed increase of SN echogenicity in PD. Rat brains were scanned after stereotactic injection of iron in different concentrations into the SN and after injecting ferritin, zinc and 6-OHDA alone, and after the addition of desferrioxamine. The amount of iron in the SN was measured spectroscopically. For iron, and partly for 6-OHDA, in different concentrations, a dose-dependent increase of SN echogenicity could be visualized, corresponding to an increase of iron measured by spectroscopy. No increase of echogenicity was visualized after the injection of ferritin and the addition of desferrioxamine to 6-OHDA, though an increase of iron was measured by spectroscopy. Therefore, we conclude that iron not bound to these proteins may lead to an increase of echogenicity of the SN.


Assuntos
Ferro/metabolismo , Substância Negra/diagnóstico por imagem , Substância Negra/metabolismo , Animais , Desferroxamina , Relação Dose-Resposta a Droga , Ferritinas , Humanos , Oxidopamina , Doença de Parkinson/diagnóstico por imagem , Doença de Parkinson/metabolismo , Projetos Piloto , Ratos , Ratos Wistar , Ultrassonografia , Zinco
17.
Percept Mot Skills ; 62(1): 59-67, 1986 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-3960684

RESUMO

The Block Design test is a task utilizing spatial ability, on which subjects are required to arrange red and white blocks in a pattern similar to one presented on a stimulus card. 69 right-handed subjects were presented a series of trials which varied in difficulty or spatial complexity. The amount of time that each subject's hand was in contact with the blocks during each of the reproduction attempts was recorded. Analysis of these times shows that subjects use their right hands with greater frequency only on tasks of low and moderate spatial complexity. This preference is not present on tasks of high spatial complexity. Interpretations of this finding are offered.


Assuntos
Lateralidade Funcional/fisiologia , Mãos/fisiologia , Percepção Espacial/fisiologia , Adolescente , Adulto , Córtex Cerebral/fisiologia , Feminino , Humanos , Masculino
18.
Exp Diabetes Res ; 2011: 212571, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21754917

RESUMO

Insulin signaling depends on tyrosine phosphorylation of insulin receptor substrates (IRSs) to mediate downstream effects; however, elevated serine phosphorylation of IRS impairs insulin signaling. Here, we investigated IRS protein expression patterns in dorsal root ganglia (DRG) of mice and whether their signaling was affected by diabetes. Both IRS1 and IRS2 are expressed in DRG; however, IRS2 appears to be the prevalent isoform and is expressed by many DRG neuronal subtypes. Phosphorylation of Ser(731)IRS2 was significantly elevated in DRG neurons from type 1 and type 2 diabetic mice. Additionally, Akt activation and neurite outgrowth in response to insulin were significantly decreased in DRG cultures from diabetic ob/ob mice. These results suggest that DRG neurons express IRS proteins that are altered by diabetes similar to other peripheral tissues, and insulin signaling downstream of the insulin receptor may be impaired in sensory neurons and contribute to the pathogenesis of diabetic neuropathy.


Assuntos
Diabetes Mellitus Experimental/complicações , Neuropatias Diabéticas/metabolismo , Neuropatias Diabéticas/fisiopatologia , Proteínas Substratos do Receptor de Insulina/metabolismo , Resistência à Insulina/fisiologia , Neurônios/metabolismo , Transdução de Sinais/fisiologia , Animais , Células Cultivadas , Diabetes Mellitus Experimental/induzido quimicamente , Modelos Animais de Doenças , Gânglios Espinais/metabolismo , Insulina/metabolismo , Insulina/farmacologia , Resistência à Insulina/genética , Leptina/genética , Leptina/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neuritos/efeitos dos fármacos , Obesidade/genética , Obesidade/metabolismo , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Estreptozocina/efeitos adversos
20.
Phys Chem Chem Phys ; 11(19): 3767-74, 2009 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-19421490

RESUMO

Metal oxide nanoparticles can be fabricated under high control via nonaqueous sol-gel synthesis. This route has been shown to lead to highly crystalline, uniform nanostructures, which explains the high and growing interest it is receiving. The underlying mechanisms are, however, so far only rudimentarily understood on a molecular scale. Here, we applied in situ FTIR spectroscopy and other techniques to monitor the nonaqueous synthesis of titania nanoparticles that can be easily stabilised in polar solvents and thus, possess high potential for application. A special focus is put on the kinetics of the organic condensation mechanisms enabling the reaction of the precursor to the inorganic nanoparticles. By comparing these kinetics to the process of nanoparticle formation monitored via complementary methods such as TEM and dynamic light scattering, a detailed insight into the principles and mechanisms of nanoparticle formation via the nonaqueous sol-gel synthesis is achieved.

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