RESUMO
Herein, we introduce the first diphenylalanine dipeptide hydrogelator capped with the cinnamoyl functional group (Cin-L-F-L-F). We evaluate the effects of the cinnamoyl moiety on molecular self-assembly events and resultant physical properties of the hydrogel formed. In addition, we report our preliminary results of this dipeptide's cytotoxicity against glioblastoma (GBM) cancer cells.
Assuntos
Dipeptídeos , Hidrogéis , Dipeptídeos/química , Dipeptídeos/farmacologia , Hidrogéis/química , Hidrogéis/farmacologia , Fenilalanina/química , Fenilalanina/farmacologiaRESUMO
BACKGROUND: Advances in diagnostic and therapeutic strategies in oncology have significantly increased the chance of survival of cancer patients, even those with metastatic disease. However, cancer-related cognitive impairment (CRCI) is frequently reported in patients treated for non-central nervous system cancers, particularly during and after chemotherapy. DESIGN: This review provides an update of the state of the art based on PubMed searches between 2012 and March 2019 on 'cognition', 'cancer', 'antineoplastic agents' or 'chemotherapy'. It includes the most recent clinical, imaging and pre-clinical data and reports management strategies of CRCI. RESULTS: Evidence obtained primarily from studies on breast cancer patients highlight memory, processing speed, attention and executive functions as the most cognitive domains impaired post-chemotherapy. Recent investigations established that other cancer treatments, such as hormone therapies and targeted therapies, can also induce cognitive deficits. Knowledge regarding predisposing factors, biological markers or brain functions associated with CRCI has improved. Factors such as age and genetic polymorphisms of apolipoprotein E, catechol-O-methyltransferase and BDNF may predispose individuals to a higher risk of cognitive impairment. Poor performance on neuropsychological tests were associated with volume reduction in grey matter, less connectivity and activation after chemotherapy. In animals, hippocampus-based memory and executive functions, mediated by the frontal lobes, were shown to be particularly susceptible to the effects of chemotherapy. It involves altered neurogenesis, mitochondrial dysfunction or brain cytokine response. An important next step is to identify strategies for managing cognitive difficulties, with primary studies to assess cognitive training and physical exercise regimens. CONCLUSIONS: CRCI is not limited to chemotherapy. A multidisciplinary approach has improved our knowledge of the complex mechanisms involved. Nowadays, studies evaluating cognitive rehabilitation programmes are encouraged to help patients cope with cognitive difficulties and improve quality of life during and after cancer.
Assuntos
Antineoplásicos/efeitos adversos , Cognição/efeitos dos fármacos , Disfunção Cognitiva/epidemiologia , Neoplasias/tratamento farmacológico , Antineoplásicos/uso terapêutico , Apolipoproteínas E/genética , Fator Neurotrófico Derivado do Encéfalo/genética , Sobreviventes de Câncer , Catecol O-Metiltransferase/genética , Disfunção Cognitiva/induzido quimicamente , Disfunção Cognitiva/genética , Disfunção Cognitiva/terapia , Citocinas/genética , Exercício Físico , Humanos , Neoplasias/complicações , Neoplasias/epidemiologia , Neoplasias/genética , Neurogênese/efeitos dos fármacos , Polimorfismo Genético , Qualidade de VidaRESUMO
BACKGROUND: Several hypnotic drugs have been previously identified as modulators of food intake, but exact mechanisms remain unknown. Feeding behavior implicates several neuronal populations in the hypothalamic arcuate nucleus including orexigenic neuropeptide Y and anorexigenic pro-opiomelanocortin producing neurons. The aim of this study was to investigate in mice the impact of different hypnotic drugs on food consumption and neuropeptide Y or pro-opiomelanocortine mRNA expression level in the hypothalamic arcuate nucleus. METHODS: Saline control, isoflurane, thiopental, midazolam or propofol were administered to C57Bl/6 mice. Feeding behavior was evaluated during 6 h. In situ hybridization of neuropeptide Y and pro-opiomelanocortine mRNAs in the hypothalamus brain region was also performed. Data were analyzed by Kruskal Wallis test and analysis of variance (p < 0.05). RESULTS: Midazolam, thiopental and propofol induced feeding behavior. Midazolam and thiopental increased neuropeptide Y mRNA level (respectively by 106 and 125%, p < 0.001) compared with control. Propofol and midazolam decreased pro-opiomelanocortine mRNA level by 31% (p < 0,01) compared with control. Isoflurane increased pro-opiomelanocortine mRNA level by 40% compared with control. CONCLUSION: In our murine model, most hypnotics induced food consumption. The hypnotic-induced regulation of neuropeptide Y and pro-opiomelanocortine hypothalamic peptides is associated with this finding. Our data suggest that administration of some hypnotic drugs may affect hypothalamic peptide precursor and neuropeptide expression and concomittantly modulate food intake. Thus, this questions the choice of anesthetics for better care management of patients undergoing major surgery or at risk of undernutrition.
Assuntos
Anestésicos/farmacologia , Núcleo Arqueado do Hipotálamo/metabolismo , Comportamento Alimentar/efeitos dos fármacos , Neuropeptídeo Y/biossíntese , Pró-Opiomelanocortina/biossíntese , Animais , Masculino , CamundongosRESUMO
The hypothalamus senses hormones and nutrients in order to regulate energy balance. In particular, detection of hypothalamic glucose levels has been shown to regulate both feeding behavior and peripheral glucose homeostasis, and impairment of this regulatory system is believed to be involved in the development of obesity and diabetes. Several data clearly demonstrate that glial cells are key elements in the perception of glucose, constituting with neurons a "glucose-sensing unit". Characterization of this interplay between glia and neurons represents an exciting challenge, and will undoubtedly contribute to identify new candidates for therapeutic intervention. The purpose of this review is to summarize the current data that stress the importance of glia in central glucose-sensing. The nature of the glia-to-neuron signaling is discussed, with a special focus on the endozepine ODN, a potent anorexigenic peptide that is highly expressed in hypothalamic glia.
Assuntos
Comunicação Celular/fisiologia , Glucose/metabolismo , Hipotálamo , Neuroglia , Neurônios , Transdução de Sinais/fisiologia , Animais , Humanos , Hipotálamo/citologia , Hipotálamo/metabolismo , Neuroglia/citologia , Neuroglia/metabolismo , Neurônios/citologia , Neurônios/metabolismoRESUMO
BACKGROUND: Responding to psychosocial needs of patients is an important element of medical practice and is dependent on the psychosocial abilities of the physician. One of the aims of teaching doctor-patient communication in medical schools is to strengthen these qualities. We assessed changes in the psychosocial abilities of first-year medical students participating in a year-long clinical communication course. METHODS: Sixty-eight first-year medical students and 49 students from the Medical Laboratories School (control group) participated in the study. The students completed, once each at the beginning (October) and at the end (July) of the course, a structured questionnaire that included a psychosocial abilities measure and sociodemographic details. RESULTS: No significant differences were found between the two groups of students regarding their sociodemographic characteristics. Furthermore, the medical students and the control group did not differ significantly in their psychosocial abilities mean scores at the beginning of the communication course (baseline). At the end of the course, a significant improvement in mean scores was found among medical students compared with an insignificant decline among the control group. CONCLUSION: Participation in an extensive clinical doctor-patient communication course guided by multidisciplinary teams may strengthen psychosocial abilities of medical students. The study needs to be replicated with a larger sample size.
Assuntos
Comunicação , Educação de Graduação em Medicina , Relações Médico-Paciente , Estudantes de Medicina , Competência Clínica , Feminino , Humanos , Masculino , Inquéritos e QuestionáriosRESUMO
Hepatopulmonary syndrome (HPS) is present in 10-32% of chronic liver disease patients, carries a poor prognosis and is treatable by liver transplantation (LT). Previous reports have shown high LT mortality in HPS and severe HPS (arterial oxygen (PaO(2)) < or =50 mmHg). We reviewed outcomes in HPS patients who received LT between 2002 and 2008 at two transplant centers supported by a dedicated HPS clinic. We assessed mortality, complications and gas exchange in 21 HPS patients (mean age 51 years, MELD score 14), including 11/21 (52%) with severe HPS and 5/21 (24%) with living donor LT (median follow-up 20.2 months after LT). Overall mortality was 1/21 (5%); mortality in severe HPS was 1/11 (9%). Peritransplant hypoxemic respiratory failure occurred in 5/21 (24%), biliary complications in 8/21 (38%) and bleeding or vascular complications in 6/21 (29%). Oxygenation improved in all 19 patients in whom PaO(2) or SaO(2) were recorded. PaO(2) increased from 52.2 +/- 13.2 to 90.3 +/- 11.5 mmHg (room air) (p < 0.0001) (12 patients); a higher baseline macroaggregated albumin shunt fraction predicted a lower rate of postoperative improvement (p = 0.045) (7 patients). Liver transplant survival in HPS and severe HPS was higher than previously demonstrated. Severity of HPS should not be the basis for transplant refusal.
Assuntos
Síndrome Hepatopulmonar/mortalidade , Síndrome Hepatopulmonar/terapia , Transplante de Fígado/mortalidade , Adulto , Síndrome Hepatopulmonar/diagnóstico , Humanos , Doadores Vivos , Pessoa de Meia-Idade , Oxigênio , Oxigenoterapia/mortalidade , Período Pós-Operatório , Resultado do TratamentoRESUMO
CONTEXT: The Psychological Medicine Inventory (PMI) was first developed to measure physicians' reported interest level, confidence and perceived ability to address the psychological aspects of patient care. A student version of this scale has since been proposed (PMI-S). OBJECTIVE: To further examine the psychometric properties of responses to this student version and to confirm a 2-factor response structure. METHODS: A total of 213 first-year medical students at Ben-Gurion University of the Negev participated in this study. They completed the PMI-S (translated into Hebrew) and a socio-demographic questionnaire. The viability of the 2-factor structure of PMI-S responses was assessed using confirmatory factor analysis (CFA). FINDINGS: Consistent with the original English language version, CFA supported a 2-factor solution (i.e., psychological abilities and psychological sensitivity). All goodness-of-fit indices were found to be within ideal parameters. DISCUSSION AND CONCLUSIONS: Results of this study suggest that the PMI-S can be used to assess psychosocial competence and abilities of medical students and to evaluate the effectiveness of psycho-educational programs aimed at improving their psychosocial abilities.
Assuntos
Atitude do Pessoal de Saúde , Educação Médica , Psicometria , Faculdades de Medicina , Estudantes de Medicina/psicologia , Adolescente , Adulto , Coleta de Dados , Demografia , Análise Fatorial , Feminino , Humanos , Idioma , Masculino , Modelos Estatísticos , Médicos/psicologia , Inquéritos e Questionários , Adulto JovemRESUMO
OBJECTIVES: To explore the association between depressive symptoms and risk for malnutrition in hospitalized elderly people. METHODS: 195 hospitalized medical patients older than 65 years of age were studied in a cross-sectional design. Depression was assessed by 30-item Geriatric Depression Scale (GDS), nutritional status was evaluated by the Mini-Nutritional Assessment (MNA). Eating and digestive problems were assessed using selected items of Nutrition Risk Index (NRI), cognitive and functional status by Folstein and Barthel indices respectively; demographic data, diagnoses and medications were obtained from medical records. RESULTS: The prevalence of depression in the studied population was 28%. MNA scores were significantly lower among depressed patients as compared with non-depressed (22.86 vs. 24.96, p < 0.001), indicating a higher risk for undernutrition among depressed persons. After controlling for age, cognitive status, functional ability, and number of illnesses, undernutrition was significantly associated with depression (OR = 2.23; 95% CI: 1.04-4.8). CONCLUSIONS: Nutritional risk is associated with depression in aged inpatients. Close case management of the elderly hospitalized patients that include assessment and treatment for both disorders may be beneficial.
Assuntos
Depressão/epidemiologia , Hospitalização , Desnutrição/epidemiologia , Estado Nutricional , Atividades Cotidianas , Idoso , Idoso de 80 Anos ou mais , Comorbidade , Estudos Transversais , Feminino , Humanos , Masculino , Avaliação Nutricional , Fatores de RiscoRESUMO
OBJECTIVES: Intracranial aneurysms are rare in children although giant aneurysms more commonly occur in adolescence. The aims of our study were to perform an extensive review of the literature over the past two decades and assess intracranial aneurysm management. METHODS: Based on a Pubmed search, we carried out a review of the literature from 1990 to 2012 regarding giant intracranial aneurysms diagnosed in the paediatric population. This descriptive study concerned clinical presentation, cerebral aneurysm characteristics, therapeutic management procedures and outcome. RESULTS: Forty-six cases were reported in 31 papers. The male/female sex ratio was 1.15, the clinical presentation was a tumour mass syndrome in 56.6%, followed by rupture in 30.4%. The aneurysm location was the posterior circulation in 41.3%, and microsurgical treatment (52.2%) predominated over endovascular coiling (28.3%). CONCLUSION: To date, no evidence-based medicine recommendation has been accepted for the management of rare intracranial aneurysms. Each reported patient was the object of a multidisciplinary clinical decision. Management of this challenging pathology should be performed on a case-to-case basis.
Assuntos
Angiografia Cerebral , Revascularização Cerebral , Embolização Terapêutica , Aneurisma Intracraniano/terapia , Procedimentos Neurocirúrgicos , Angiografia Cerebral/métodos , Revascularização Cerebral/métodos , Embolização Terapêutica/métodos , Humanos , Aneurisma Intracraniano/diagnóstico , Procedimentos Neurocirúrgicos/métodos , Resultado do TratamentoRESUMO
PURPOSE: To assess long-term neurodevelopmental outcome in children with hydrocephalus requiring neurosurgical treatment during the neonatal period. METHODS: This prospective longitudinal population-based study included 43 children with neonatal shunted hydrocephalus. The 43 children were prospectively reviewed in the presence of their parents at the outpatient clinic. Cognitive and motor outcomes were assessed respectively using different Wechsler scales according to age and Gross Motor Function Classification System (GMFCS). Postoperative MRI was routinely performed. RESULTS: The mean gestational age at birth of the 43 consecutive children with neonatal hydrocephalus (sex ratio M/F: 1.39) was 34.5±5.4 weeks of gestation. At mean follow-up of 10.4±4 years, mean total IQ was 73±27.7, with equivalent results in mean verbal and mean performance IQ. Of the 33 children with IQ evaluation, 18 presented an IQ≥85 (41.9%). Efficiency in walking without a mobility device (GMFCS≤2) was obtained in 37 children (86%). Only severity of postoperative ventricular dilation was significantly associated with unfavorable outcome (Evans index>0.37; odds ratio: 0.16, P=0.03). CONCLUSION: This information could be provided to those families concerned who often experience anxiety when multi-disciplinary management of neonatal hydrocephalus is required.
Assuntos
Hidrocefalia/cirurgia , Doenças do Prematuro/cirurgia , Transtornos do Neurodesenvolvimento/etiologia , Complicações Pós-Operatórias/prevenção & controle , Derivação Ventriculoperitoneal , Ventriculostomia , Anormalidades Múltiplas , Neoplasias do Ventrículo Cerebral/complicações , Neoplasias do Ventrículo Cerebral/cirurgia , Feminino , Seguimentos , Idade Gestacional , Humanos , Hidrocefalia/complicações , Hidrocefalia/diagnóstico por imagem , Recém-Nascido , Recém-Nascido Prematuro , Deficiência Intelectual/epidemiologia , Deficiência Intelectual/etiologia , Deficiência Intelectual/prevenção & controle , Imageamento por Ressonância Magnética , Masculino , Transtornos dos Movimentos/epidemiologia , Transtornos dos Movimentos/etiologia , Transtornos dos Movimentos/prevenção & controle , Transtornos do Neurodesenvolvimento/epidemiologia , Transtornos do Neurodesenvolvimento/prevenção & controle , Complicações Pós-Operatórias/diagnóstico por imagem , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Estudos Prospectivos , Índice de Gravidade de Doença , Resultado do TratamentoRESUMO
Multiform glioblastomas (GBM) are the most frequent and aggressive primary brain tumors in adults. The poor prognosis is due to neo-angiogenesis and cellular invasion, processes that require complex chemotaxic mechanisms involving motility, migration and adhesion. Understanding these different cellular events implies identifying receptors and transduction pathways that lead to and promote either migration or adhesion. Here we establish that glioma express the vasoactive peptide urotensin II (UII) and its receptor UT and that UT-mediated signaling cascades are involved in glioma cell migration and adhesion. Components of the urotensinergic systems, UII and UT, are widely expressed in patient-derived GBM tissue sections, glioma cell lines and fresh biopsy explants. Interestingly, gradient concentrations of UII produced chemoattracting migratory/motility effects in glioma as well as HEK293 cells expressing human UT. These effects mainly involved the G13/Rho/rho kinase pathway while partially requiring Gi/o/PI3K components. In contrast, we observed that homogeneous concentrations of UII drastically blocked cell motility and stimulated cell-matrix adhesions through a UT/Gi/o signaling cascade, partially involving phosphatidylinositol-3 kinase. Finally, we provide evidence that, in glioma cells, homogeneous concentration of UII allowed translocation of Gα13 to the UT receptor at the plasma membrane and increased actin stress fibers, lamellipodia formation and vinculin-stained focal adhesions. UII also provoked a re-localization of UT precoupled to Gαi in filipodia and initiated integrin-stained focal points. Altogether, these findings suggest that UT behaves as a chemotaxic receptor, relaying a signaling switch between directional migration and cell adhesion under gradient or homogeneous concentrations, thereby redefining sequential mechanisms affecting tumor cells during glioma invasion. Taken together, our results allow us to propose a model in order to improve the design of compounds that demonstrate signaling bias for therapies that target specifically the Gi/o signaling pathway.
Assuntos
Neoplasias Encefálicas/metabolismo , Quimiotaxia , Glioblastoma/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Transdução de Sinais , Urotensinas/metabolismo , Actinas/metabolismo , Biópsia , Neoplasias Encefálicas/patologia , Glioblastoma/patologia , Humanos , PolimerizaçãoRESUMO
Nitric oxide (NO) is implicated in the regulation of various endocrine functions, but the effect of NO on GABA(A) receptor transmission has never been reported in endocrine cells. In the present study, we have investigated the effects of various agents acting on the NO transduction pathway on GABA(A) receptor function in frog pituitary melanotrophs. Histochemical studies using the NADPH-diaphorase reaction and immunohistochemical labeling with antibodies against neuronal NO synthase (nNOS) revealed that nNOS is expressed in the intermediate lobe of the pituitary and in cultured melanotrophs. Whole-cell patch-clamp recordings showed that the specific substrate of NOS L-arginine (L-Arg, 10(-4) M) or the NO donor sodium nitroprusside (10(-5) M) provoked a long-lasting inhibition of the current evoked by GABA (5 x 10(-6) M). The NOS inhibitor L-nitroarginine (10(-5) M) produced a biphasic effect, i.e. a transient decrease followed by a delayed increase of the GABA-evoked current amplitude. Similarly, the specific nNOS inhibitor 7-nitroindazole and the specific inducible NOS (iNOS) inhibitor aminoguanidine (10(-5) M each) provoked a transient depression of the current followed by a sustained potentiation. Formation of cGMP in neurointermediate lobes was enhanced by L-Arg (10(-4) M) and by the calcium-releasing agent caffeine (10(-4) M), and inhibited by the calmodulin (CaM)/Ca2+ complex blocker W7 (10(-5) M). The GABA-evoked current was potentiated by the guanylyl cyclase inhibitor ODQ (10(-8)-10(-7) M) and inhibited by the protein kinase G (PKG) activator 8pCPT-cGMP (3 x 10(-7)-3 x 10(-5) M). The present data indicate that NO, produced by a CaM/Ca2+-dependent NOS in frog melanotrophs, exerts an autocrine inhibitory effect on the GABA-evoked current. The action of NO on the GABA(A) receptor function is mediated through activation of the cGMP/PKG pathway.
Assuntos
Hormônios Estimuladores de Melanócitos/metabolismo , Óxido Nítrico/fisiologia , Hipófise/metabolismo , Receptores de GABA-A/metabolismo , Animais , GMP Cíclico/metabolismo , Eletrofisiologia , Inibidores Enzimáticos/farmacologia , Imuno-Histoquímica , Indicadores e Reagentes , NADPH Desidrogenase/metabolismo , Óxido Nítrico/biossíntese , Doadores de Óxido Nítrico/farmacologia , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico Sintase Tipo I , Técnicas de Patch-Clamp , Fosforilação , Hipófise/citologia , Rana ridibunda , alfa-MSH/metabolismoRESUMO
The direct effects of nitric oxide (NO) donors and sulfhydryl-modifying agents on the GABA(A) receptor function were examined by perforated patch, whole-cell and single channel recordings in cultured frog melanotrophs. In amphotericin B-perforated cells incubated with the soluble guanylyl cyclase inhibitors LY 83583 and ODQ (10-4 M each), the NO donor sodium nitroprusside (SNP) (10(-3) M) reversibly increased the current evoked by GABA (5 x 10(-6) M). In the whole-cell configuration, internal application of the oxidizing agent H2O2 (0.05%) potentiated the GABA-evoked current while the reducing agent 2-mercaptoethanol (5 x 10(-3) M) slightly decreased the current amplitude. In inside-out patches, GABA (2 x 10(-7) M) triggered single channel bursts of openings. Incubation with the NO donors SNP or DEA/NO (10(-4) M each) enhanced the open probability of the GABA(A) receptor channel but did not modify the chloride reversal potential and did not affect the conductance states. The oxidizing agents H2O2 (0.05%) or DTNB (10-4 M) mimicked the stimulatory effect of the NO donors on the open probability while the reducing compounds 2-mercaptoethanol (5 x 10(-3) M) or DTT (10(-4) M) markedly attenuated the channel activity. Potentiation of the GABA-induced single channel activity by SNP or H2O2 was blocked by 2-mercaptoethanol. Similarly, the potentiating effect produced by DEA/NO or DTNB on the open probability was reversed by DTT. In outside-out patches, incubation with SNP also significantly enhanced the open probability of single channels activated by GABA (10(-6) M). These data indicate that, in frog pituitary melanotrophs, NO potentiates the GABA-evoked current independently of the cGMP/protein kinase pathway. The effect of NO can be accounted for by S-nitrosylation/oxidation of thiol groups either directly on the GABA(A) receptor subunits or on a regulatory protein tightly associated with the GABA(A) receptor.
Assuntos
Melanócitos/metabolismo , Óxido Nítrico/metabolismo , Hipófise/metabolismo , Receptores de GABA-A/metabolismo , Aminoquinolinas/farmacologia , Animais , GMP Cíclico/metabolismo , Proteínas Quinases Dependentes de GMP Cíclico/metabolismo , Ácido Ditionitrobenzoico/farmacologia , Condutividade Elétrica , Inibidores Enzimáticos/farmacologia , Hidrazinas/farmacologia , Ativação do Canal Iônico/efeitos dos fármacos , Ativação do Canal Iônico/fisiologia , Masculino , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Mercaptoetanol/farmacologia , Doadores de Óxido Nítrico/farmacologia , Óxidos de Nitrogênio , Nitroprussiato/farmacologia , Oxidiazóis/farmacologia , Oxirredução , Técnicas de Patch-Clamp , Hipófise/citologia , Quinoxalinas/farmacologia , Rana ridibunda , Reagentes de Sulfidrila/farmacologia , Ácido gama-Aminobutírico/farmacologiaRESUMO
The effects of protein tyrosine kinase (PTK) and PTK inhibitors on the GABAA receptor function were studied in cultured frog pituitary melanotrophs by using the patch-clamp technique. Extracellular application of the PTK inhibitors genistein (10-9 to 10-5 M) or lavendustin A (10-12 to 10-7 M) provoked a bell-shaped potentiation of the whole-cell current induced by GABA (3x10-6 M). In contrast, at high concentrations, genistein (10-4 M) and lavendustin A (10-5 M) reversibly reduced the GABA-evoked current. Daidzein and lavendustin B, the inactive analogs of genistein and lavendustin A, respectively, did not modify the current induced by GABA. In the inside-out configuration, bath application of the recombinant PTK pp60c-src (75 U/ml) inhibited the GABA-activated chloride current, and the inhibitory effect of pp60c-src was prevented by genistein (10-7 M). Immunoblotting revealed that genistein, at doses of 10-7 M or 10-4 M, markedly inhibited tyrosine phosphorylation of the beta2/beta3 subunits of the GABAA receptor. Extracellular application of the PKA activator Bt2cAMP (10-3 M), the PKA/PKC inhibitor H7 (10-5 M) and the Cam KII inhibitor W7 (10-5 M) reversibly diminished the whole-cell GABA-induced current. Internal application of H7 and W7 (10-4 M) did not modify the dose-dependent effects of genistein. Internal application of sodium orthovanadate (10-4 M), a protein tyrosine phosphatase inhibitor, decreased the GABA-evoked current and markedly reduced the potentiating effect of genistein. The present study provides the first evidence that, in frog pituitary melanotrophs, the GABAA receptor is phosphorylated at least on its beta2/beta3 subunits by an endogenous PTK. Our data also demonstrate that tyrosine phosphorylation exerts an inhibitory effect on GABAA receptor function.
Assuntos
Hipófise/fisiologia , Proteínas Tirosina Quinases/metabolismo , Receptores de GABA-A/fisiologia , Ácido gama-Aminobutírico/farmacologia , 1-(5-Isoquinolinasulfonil)-2-Metilpiperazina/farmacologia , Trifosfato de Adenosina/farmacologia , Animais , Células Cultivadas , Inibidores Enzimáticos/farmacologia , Potenciais Evocados/efeitos dos fármacos , Genisteína/farmacologia , Técnicas de Patch-Clamp , Fenóis/farmacologia , Hipófise/citologia , Hipófise/efeitos dos fármacos , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Proto-Oncogênicas pp60(c-src)/metabolismo , Rana ridibunda , Receptores de GABA-A/efeitos dos fármacos , Sulfonamidas/farmacologia , Vanadatos/farmacologiaRESUMO
The effects of adenosine on the voltage-sensitive delayed-rectifier K+ (IK) currents and hyperpolarization-activated cationic inward current (Ih) were studied in cultured frog melanotrophs using the whole-cell configuration of the patch-clamp technique. The A1 receptor agonist R-N6-phenylisopropyl-adenosine (R-PIA; 50 microM) reversibly increased IK. Perfusion of dibutyryl-cAMP (1 mM) in the external solution did not modify the R-PIA-induced enhancement of IK. Pretreatment of melanotrophs with pertussis toxin (1 microg/ml; 12 h) totally abolished the R-PIA-evoked response. Application of hyperpolarizing voltage pulses from -60 to -120 mV to melanotrophs induced a two-component inward current corresponding to an Ih-like conductance. This conductance was characterized by a high K+ selectivity and a low Na+ permeability and was resistant to tetrodotoxin (1 microM). R-PIA had no effect on Ih. The present study demonstrates that in frog melanotrophs adenosine inhibits the electrical activity by activating IK through an A1 receptor subtype coupled to a pertussis toxin-sensitive pathway independent of the cAMP/PKA system. This study also demonstrates the existence of a Ih conductance in frog melanotrophs which is not modulated by A1 receptors.
Assuntos
Adenosina/fisiologia , Canais Iônicos/fisiologia , Hormônios Estimuladores de Melanócitos/fisiologia , Hipófise/fisiologia , Canais de Potássio de Abertura Dependente da Tensão da Membrana , Canais de Potássio/fisiologia , Adenosina/análogos & derivados , Adenosina/farmacologia , Animais , Células Cultivadas , Canais de Cátion Regulados por Nucleotídeos Cíclicos , Canais de Potássio de Retificação Tardia , Sinergismo Farmacológico , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização , Canais Iônicos/metabolismo , Masculino , Hormônios Estimuladores de Melanócitos/metabolismo , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Fármacos Neuroprotetores/farmacologia , Técnicas de Patch-Clamp , Hipófise/citologia , Hipófise/efeitos dos fármacos , Canais de Potássio/metabolismo , Agonistas do Receptor Purinérgico P1 , Rana ridibundaRESUMO
The action of steroids on the bioelectrical response to gamma-aminobutyric acid (GABA) has never been studied in pituitary cells. In the present study, we have thus investigated the effects of a series of neuroactive steroids on the GABA-activated current in frog melanotrope cells in primary culture, using the patch-clamp technique in the whole-cell configuration. Bath perfusion of 3alpha-isomers of pregnanolone or tetrahydrodeoxycorticosterone (1 microM) significantly enhanced the current evoked by short pulses of GABA (3 microM) and accelerated its desensitization. In contrast, the 3beta-isomers (30 microM) had no effect on the GABA-activated current. Addition to the bath solution of dehydroepiandrosterone or dehydroepiandrosterone sulfate (10 microM) inhibited the GABA-activated current without modifying its kinetics while pregnenolone sulfate (10 microM) both inhibited the GABA-activated current and accelerated its decay rate. The effects of pregnane steroids were not impaired by the central-type benzodiazepine receptor antagonist flumazenil (10 microM). In conclusion, the present study reveals that neuroactive steroids may exert multiple modulatory activities on the GABA(A) receptor borne by melanotrope cells. The effect of steroids on the current evoked by GABA is rapid, reversible, stereospecific and not mediated through the benzodiazepine binding site of the GABA(A) receptor.
Assuntos
Neurotransmissores/farmacologia , Hipófise/citologia , Hipófise/efeitos dos fármacos , Receptores de GABA-A/efeitos dos fármacos , Esteroides/farmacologia , Animais , Células Cultivadas , Desidroepiandrosterona/farmacologia , Eletrofisiologia , Moduladores GABAérgicos/farmacologia , Técnicas de Patch-Clamp , Pentobarbital/farmacologia , Pregnenolona/farmacologia , Rana ridibunda , Ácido gama-Aminobutírico/fisiologiaRESUMO
To determine the frequency, severity and predictors of bleeding and azotemia after envenomation in humans by Echis coloratus, a retrospective survey of 68 cases in Israel between 1970 and 1989 was carried out. We used univariate and multivariate analyses of clinical variables on admission for the outcome variables of bleeding, hemoglobin and platelet levels, and blood urea. Within hours or days after envenomation, a major bleeding episode occurred in 18% of the victims, a drop in hemoglobin to 10 g/dliter or less in 14%, and an increase in blood urea to 9 mmole/liter or more in 15%. These complications correlated with time interval between envenomation and hospital admission, and the following admission variables: degree of bleeding, hemoglobin level, platelet and white blood cell counts, blood urea and proteinuria. Complications were unlikely in patients who were presented with all of the following: a hemoglobin level of 13 g/dliter or more, a platelet count of 100,000/mm3 or more, a blood urea level of 7 mmole/liter or less, no proteinuria and no bleeding. Treatment on admission with a specific monovalent antiserum was associated with a shorter duration of hemostatic failure and a reduced incidence of anemia and thrombopenia. Infusion of fresh frozen plasma on admission did not appear to be effective in preventing complications.
Assuntos
Anemia/etiologia , Hemorragia/etiologia , Mordeduras de Serpentes/complicações , Uremia/etiologia , Adulto , Fatores Etários , Anemia/prevenção & controle , Animais , Feminino , Seguimentos , Hemoglobinas/análise , Hemorragia/prevenção & controle , Humanos , Imunização Passiva , Israel/epidemiologia , Contagem de Leucócitos , Masculino , Plasma , Contagem de Plaquetas , Probabilidade , Estudos Retrospectivos , Fatores de Risco , Mordeduras de Serpentes/sangue , Mordeduras de Serpentes/epidemiologia , Mordeduras de Serpentes/terapia , Uremia/prevenção & controleRESUMO
Aging and Alzheimer's disease (AD) have been the subject of many studies. It has been suggested that chromosomal alterations may be involved in the etiology and/or pathogenesis of ageing and AD. The purpose of the present study was to examine the effect of diepoxybutane (DEB) on lymphocyte chromosomal instability in the elderly. We examined lymphocytes cytogenetically with, as well as, without DEB treatment, in a group of 12 elderly (range of age 72-96 years), nine of them suffering from AD type. Without DEB treatment six of the donors expressed chromosomal instability in at least 6% of the analyzed cells. After treatment with DEB, lymphocytes showed an increase in the chromosomal instability in up to 20% of the analyzed in eight donors. The sex chromosomes were the main chromosomes involved in the acquired chromosomal abnormalities. It is not clear from this study whether this chromosomal instability is related to the AD. The significance of the involvement of sex chromosomes either in ageing or in AD, as well as, the question whether the chromosomal instability is the cause of or part of ageing processes, has to be addressed.
RESUMO
A case-control study was performed to evaluate factors associated with successful rehabilitation in elderly patients who sustained hip fractures. All 170 patients with fractured hips hospitalized in the geriatrics ward of the Soroka Medical Center in Beer-Sheva, Israel between 1987 and 1991 were studied. Success of rehabilitation was determined by staff evaluation of the patient's ability to walk and perform activities of daily living. The independent variables, including sociodemographic and medical variables, and mental and functional assessments, were assessed by chart reviews, staff evaluation and mental tests. One-hundred and twenty-nine patients (75.9%) were successfully rehabilitated. A normal mental state (p < 0.0001), female gender (p < 0.02) and absence of diabetes mellitus (p < 0.008) were associated significantly with successful rehabilitation.
Assuntos
Fraturas do Quadril/reabilitação , Atividades Cotidianas , Idoso , Estudos de Casos e Controles , Feminino , Fixação Intramedular de Fraturas , Fraturas do Quadril/cirurgia , Humanos , Masculino , Prognóstico , Resultado do TratamentoRESUMO
BACKGROUND: Patients with brain metastasis (BM) from renal cell carcinoma (RCC) have a poorly known prognosis due to the rarity of this disease. The aim of our study was to assess the outcome of patients with a BM due to RCC, and to determine the predictive factors for survival. METHODS: Consecutive patients who underwent treatment between 1997 and 2012 were identified retrospectively from a database (n=28, median age of 57.8 years, sex ratio M/F: 3.7). Main criteria collected concerned survival time. Other data collected were relative to initial histology, clinical findings at the time of BM diagnosis (diagnosis circumstances, KPS), radiological findings and BM characteristics (number, size and localization), treatment of BM (including surgery, stereotactic radiosurgery [SRS], systemic treatments, whole brain radiotherapy [WBRT]) and the outcome of surgery if performed. Statistical analysis of survival was performed using the Kaplan-Meier method. RESULTS: Median survival was 13.3 months, 1-year survival was 60.2%, 2-year survival was 16.4%. Univariate analysis showed the existence of intracranial hypertension (P=0.01), other systemic metastasis (P=0.049), the absence of deep metastasis (P=0.03) which are all linked to shorter survival. Age, KPS, initial histology of RCC, number, size, localization, and hemorrhage in BM were not correlated to survival. The median survival in the surgical resection group was 25.3 months versus 8.6 months (P=0.02). The main criteria for the selection of the surgical group were a single BM (P=0.04), and superficial metastasis (P=0.02). CONCLUSIONS: Three predictive factors for longer survival in BMRCC were the absence of intracranial hypertension, the absence of acute metastasis and the absence of extracranial metastasis. Surgical removal, when possible, seems to benefit patient survival.