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1.
Gesundheitswesen ; 77(1): 16-23, 2015 Jan.
Artigo em Alemão | MEDLINE | ID: mdl-24566836

RESUMO

INTRODUCTION: After the hospital discharge of older patients with multiple morbidities, GPs are often faced with the task of prioritising the patients' drug regimens so as to reduce the risk of overmedication. AIM: How do GPs prioritise such medications in multimorbid elderly patients at the transition between inpatient and home care? The experience by the GPs is documented in typical case vignettes. METHOD: 44 GPs in Sachsen-Anhalt were recruited--they were engaged in focus group discussions and interviewed using semi-standardised questionnaires. Typical case vignettes were developed, relevant to the everyday care that elderly patients would typically receive from their GPs with respect to their drug optimisation. RESULTS: According to the results of the focus groups, the following issues affect GPs' decisions: drug and patient safety, their own competence in the health system, patient health literacy, evidence base, communication between secondary and primary care (and their respective influences on each other). When considering individual cases, patient safety, patient wishes, and quality of life were central. This is demonstrated by the drug dispositions of one exemplary case vignette. CONCLUSIONS: GPs do prioritise drug regimens with rational criteria. Initial problem delineation, process documentation and the design of a transferable product are interlinking steps in the development of case vignettes. Care issues of drug therapy in elderly patients with multiple morbidities should be investigated further with larger representative samples in order to clarify whether the criteria used here are applied contextually or consistently. Embedding case vignettes into further education concepts is also likely to be useful.


Assuntos
Assistência Ambulatorial/estatística & dados numéricos , Clínicos Gerais/estatística & dados numéricos , Alocação de Recursos para a Atenção à Saúde/estatística & dados numéricos , Prioridades em Saúde/estatística & dados numéricos , Mau Uso de Serviços de Saúde/prevenção & controle , Prescrições/estatística & dados numéricos , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Coleta de Dados , Tomada de Decisões , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/prevenção & controle , Feminino , Alemanha , Alocação de Recursos para a Atenção à Saúde/métodos , Serviços de Saúde para Idosos/estatística & dados numéricos , Serviços de Assistência Domiciliar , Humanos , Masculino , Conduta do Tratamento Medicamentoso/estatística & dados numéricos , Pessoa de Meia-Idade , Alta do Paciente/estatística & dados numéricos , Transferência de Pacientes/estatística & dados numéricos
2.
J Obstet Gynaecol ; 33(8): 798-801, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24219716

RESUMO

Postpartum haemorrhage is an infrequent but potentially life-threatening obstetrical emergency amenable to simulation. An educational programme consisting of a lecture and high-fidelity simulation exercise was given to incoming obstetrics and gynaecology (OB) and family medicine (FM) residents. Residents reported pre- and post-intervention confidence scores on a 1-5 Likert scale and a subset completed a postpartum haemorrhage knowledge assessment. Residents reported significant improvements in confidence in parameters involved in diagnosis and management of postpartum haemorrhage. The postpartum haemorrhage test mean scores significantly increased (57.4 ± 9.6% vs 77.1 ± 7.9%, p < 0.01) and were significantly correlated to confidence scores (Spearman's coefficient of 0.651, p < 0.001). In conclusion, an education programme that incorporates high-fidelity simulation of postpartum haemorrhage improves the confidence and knowledge of incoming residents and appears to be an effective educational approach.


Assuntos
Obstetrícia/educação , Hemorragia Pós-Parto/terapia , Competência Clínica , Feminino , Humanos , Internato e Residência/estatística & dados numéricos , Simulação de Paciente , Gravidez
3.
Endocrinology ; 147(10): 4968-76, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16794011

RESUMO

Ulcerative colitis is a multifactorial disease, with immunological, genetic, and environmental factors playing an important role in its pathogenesis. Here we investigated the consequences of exposure to chronic psychosocial stress on the severity of a dextran sulfate sodium (DSS)-induced colitis in male C57BL/6 mice. Chronic stress was induced by repeated exposure to social defeat (SD, 2 h) and overcrowding (OC, 24 h) during 19 consecutive days. SD/OC mice showed a diminished body weight gain, thymus-atrophy, and adrenal hypertrophy, but similar light-phase plasma corticosterone concentrations, compared with unstressed mice. In contrast, the rise in dark-phase corticosterone concentration was significantly attenuated in SD/OC mice, whereas plasma ACTH concentrations and hypothalamic CRH mRNA expression did not differ between stressed and nonstressed groups. Additionally, adrenal cells from SD/OC mice showed a decreased in vitro response to ACTH stimulation. Subsequent treatment with 1% DSS for 7 d resulted in a more severe intestinal inflammation in SD/OC mice, as reflected by an increase in body weight loss, histological damage scores, and secretion of IL-6, TNFalpha, and interferon-gamma from mesenteric lymph node cells and by decreased colon length. The impaired health status of stressed mice was also reflected by a significantly lower survival rate after termination of the DSS treatment. In conclusion, the present findings demonstrate that chronic intermittent exposure to a psychosocial stressor before the induction of acute DSS-colitis results in adrenal insufficiency, increases in the severity of the acute inflammation, and impairs the healing phase.


Assuntos
Colite/induzido quimicamente , Colite/prevenção & controle , Aglomeração/psicologia , Sulfato de Dextrana , Regeneração/fisiologia , Predomínio Social , Estresse Psicológico/fisiopatologia , Doença Aguda , Glândulas Suprarrenais/anatomia & histologia , Glândulas Suprarrenais/crescimento & desenvolvimento , Hormônio Adrenocorticotrópico/sangue , Animais , Corticosterona/sangue , Hormônio Liberador da Corticotropina/metabolismo , Citocinas/metabolismo , Sistema Hipotálamo-Hipofisário/fisiologia , Hipotálamo/metabolismo , Linfonodos/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Sistema Hipófise-Suprarrenal/fisiologia , RNA Mensageiro/biossíntese , Estresse Psicológico/psicologia , Timo/anatomia & histologia , Timo/crescimento & desenvolvimento
4.
Anat Embryol (Berl) ; 210(5-6): 525-37, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16180018

RESUMO

Recent advances in our understanding of the basic mechanisms of epilepsy have derived, to a large extent, from increasing ability to carry out detailed studies on patients surgically treated for intractable epilepsy. Clinical and experimental perioperative studies divide into three different phases: before the surgical intervention (preoperative studies), on the intervention itself (intraoperative studies), and on the period when the part of the brain that has to be removed is available for further investigations (postoperative studies). Before surgery, both structural and functional neuroimaging techniques, in addition to their diagnostic roles, could be used to investigate the pathophysiological mechanisms of seizure attacks in epileptic patients. During epilepsy surgery, it is possible to insert microdialysis catheters and electroencephalogram electrodes into the brain tissues in order to measure constituents of extracellular fluid and record the bioelectrical activity. Subsequent surgical resection provides tissue that can be used for electrophysiological, morphological, and molecular biological investigations. To take full advantage of these opportunities, carefully designed experimental protocols are necessary to compare the data from different phases and characterize abnormalities in the human epileptic brain.


Assuntos
Encéfalo/patologia , Encéfalo/fisiopatologia , Epilepsia/cirurgia , Encéfalo/cirurgia , Eletroencefalografia , Epilepsia/patologia , Epilepsia/fisiopatologia , Humanos , Microdiálise
5.
Neuroreport ; 15(7): 1141-4, 2004 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-15129162

RESUMO

Reduction of the melanin precursor DOPA associated with albinism leads to spatiotemporal disturbances in retinal neurogenesis and thus seems to be responsible for numerous neuronal alterations found in albino retinae. To investigate whether these cellular alterations are reflected in retinal neurotransmitter concentrations we compared the levels of GABA and glutamate in the retina of adult pigmented Long Evans and albino Wistar rats using reversed phase-liquid chromatography (RP-HPLC). When normalized to retinal weight, GABA levels showed a statistically insignificant trend to be lower and glutamate values to be higher in albinos than in pigmented animals. The ratio of glutamate to GABA was significantly higher in albino than in pigmented retinae. As numerous studies have shown that the balance between GABA and glutamate plays a crucial role for establishing direction selectivity, these results are discussed in relation to direction selectivity and defects in the optokinetic system of albinos.


Assuntos
Albinismo/genética , Albinismo/metabolismo , Retina/metabolismo , Ácido gama-Aminobutírico/genética , Ácido gama-Aminobutírico/metabolismo , Animais , Feminino , Ácido Glutâmico/genética , Ácido Glutâmico/metabolismo , Masculino , Ratos , Ratos Long-Evans , Ratos Wistar , Especificidade da Espécie
6.
J Neurosci Res ; 75(6): 807-16, 2004 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-14994341

RESUMO

A-type currents powerfully modulate discharge behavior and have been described in a large number of different species and cell types. However, data on A-type currents in human brain tissue are scarce. Here we have examined the properties of a fast transient outward current in acutely dissociated human neocortical neurons from the temporal lobe of epilepsy patients by using the whole-cell voltage-clamp technique. The A-type current was isolated with a subtraction protocol. In addition, delayed potassium currents were reduced pharmacologically with 10 mM tetraethylammonium chloride. The current displayed an activation threshold of about -70 mV. The voltage-dependent activation was fitted with a Boltzmann function, with a half-maximal conductance at -14.8 +/- 1.8 mV (n = 5) and a slope factor of 17.0 +/- 0.5 mV (n = 5). The voltage of half-maximal steady-state inactivation was -98.9 +/- 8.3 mV (n = 5), with a slope factor of -6.6 +/- 1.9 mV (n = 5). Recovery from inactivation could be fitted monoexponentially with a time constant of 18.2 +/- 7.5 msec (n = 5). At a command potential of +30 mV, application of 5 mM 4-aminopyridine or 100 microM flecainide resulted in a reduction of A-type current amplitude by 35% or 22%, respectively. In addition, flecainide markedly accelerated inactivation. Current amplitude was reduced by 31% with application of 500 microM cadmium. All drug effects were reversible. In conclusion, neocortical neurons from epilepsy patients express an A-type current with properties similar to those described for animal tissues.


Assuntos
Epilepsia/fisiopatologia , Neocórtex/patologia , Neurônios/fisiologia , Valina/análogos & derivados , Adolescente , Adulto , Anestésicos Locais/farmacologia , Antiarrítmicos/farmacologia , Cádmio/farmacologia , Pré-Escolar , Feminino , Flecainida/farmacologia , Humanos , Técnicas In Vitro , Masculino , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Pessoa de Meia-Idade , Técnicas de Patch-Clamp/métodos , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio/fisiologia , Tetraetilamônio/farmacologia , Tetrodotoxina/farmacologia , Valina/farmacologia
7.
Neuroscience ; 121(3): 587-604, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-14568020

RESUMO

Stimulus-induced pattern of bioelectric activity in human neocortical tissue was investigated by use of the voltage sensitive dye RH795 and a fast optical recording system. During control conditions stimulation of layer I evoked activity predominantly in supragranular layers showing a spatial extent of up to 3000 microm along layer III. Stimulation in white matter evoked distinct activity in infragranular layers with a spatial extent of up to 3000 microm measured along layer V. The mean amplitude of optical signals close to the stimulated sites in layer I and white matter determined 25 ms following the stimulus, decreased by 50% at a lateral distance of approximately 900 microm and 1200 microm, respectively. Velocity of spread along the vertical stimulation axis reached 0.24 m/s in the supragranular layers (layers I to III) and then decreased to 0.09 m/s following layer I activation; stimulation of white matter induced a velocity of spread in layer V of 0.38 m/s, which slowed down to 0.12 m/s when passing the lower border of lamina IV. The horizontal velocities of spread determined from the stimulation site to a lateral distance of 500 microm reached 0.26-0.28 m/s and 0.28-0.35 m/s for layer I and white matter stimulation, respectively. At larger distances velocity of spread decreased. Increased excitability (Mg(2+)-free solution) had no significant effect on the spatio-temporal distribution of evoked activity as compared with control conditions. There were also no obvious differences between the results obtained in slices, which generated spontaneously sharp waves and those which were not spontaneously active. About 30% of the slices (n=7) displayed a greatly different response pattern, which seemed not to be related in a simple way to the stimulation as was the case in the majority of the investigated slices. The activity pattern of those slices appeared atypical in regard to their deviations of the vertical and horizontal extent of activity, to their reduced spatial extent of activity during increased excitability, to their layer-related distribution of activity, and to the appearance of afterdischarges.Concluding, in 30% of the human temporal lobe slices atypical activity pattern occurred which obviously reflect intrinsic epileptiform properties of the resected tissue. The majority of slices showed stereotyped activity pattern without evidence for increased excitability.


Assuntos
Potenciais Evocados/fisiologia , Neocórtex/fisiologia , Adolescente , Adulto , Mapeamento Encefálico , Criança , Pré-Escolar , Diagnóstico por Imagem/métodos , Relação Dose-Resposta à Radiação , Condutividade Elétrica , Estimulação Elétrica , Eletrofisiologia , Epilepsia do Lobo Temporal/metabolismo , Epilepsia do Lobo Temporal/fisiopatologia , Epilepsia do Lobo Temporal/cirurgia , Feminino , Corantes Fluorescentes/farmacocinética , Humanos , Técnicas In Vitro , Magnésio/metabolismo , Masculino , Pessoa de Meia-Idade , Neocórtex/anatomia & histologia , Neocórtex/metabolismo , Tempo de Reação , Estirenos/farmacocinética , Fatores de Tempo
8.
Brain Res ; 975(1-2): 129-34, 2003 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-12763600

RESUMO

Spreading depression (SD) is characterized by a transient breakdown of neuronal function concomitant with a massive failure of ion homeostasis. It is a phenomenon that can be induced in neocortical tissue by raising excitability, e.g. injection of K(+), application of glutamatergic agonists, or blocking Na(+)/K(+) ATPase. Here we report a novel method of SD induction using minimal disinhibition with application of low concentrations (5 microM) of the GABA(A) receptor blocker bicuculline. This procedure-while subthreshold for epileptiform activity-readily induced spontaneous SDs in native rat neocortical slices, accompanied by typical depolarizations of neurons and glial cells. In contrast, in human neocortical preparations obtained from epilepsy surgery, in approximately 20% of the slices spontaneous epileptiform activity appeared with this bicuculline dosage without SDs. Raising the concentration of bicuculline to an epileptogenic dose (10 microM) in human tissue also resulted in the generation of epileptiform activity only. Likewise, in slices from pilocarpine-treated, chronically epileptic rats, bicuculline also only induced epileptiform activity without eliciting SDs. The experiments indicate that chronic epilepsy causes a differential sensitivity to partial GABA(A) receptor blockade with regard to induction of SD.


Assuntos
Depressão Alastrante da Atividade Elétrica Cortical/fisiologia , Epilepsia/fisiopatologia , Neocórtex/fisiologia , 2-Amino-5-fosfonovalerato/farmacologia , Animais , Bicuculina/farmacologia , Doença Crônica , Relação Dose-Resposta a Droga , Estimulação Elétrica , Epilepsia/induzido quimicamente , Antagonistas GABAérgicos/farmacologia , Humanos , Técnicas In Vitro , Potenciais da Membrana/efeitos dos fármacos , Microeletrodos , Neuroglia/efeitos dos fármacos , Neuroglia/fisiologia , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Parassimpatomiméticos/farmacologia , Pilocarpina/farmacologia , Ratos , Receptores de GABA-A/efeitos dos fármacos , Receptores de N-Metil-D-Aspartato/efeitos dos fármacos
9.
Brain Res ; 908(2): 130-9, 2001 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-11454323

RESUMO

Extra- and intracellular recording techniques were used to study the epileptiform activity generated by guinea-pig hippocampal slices perfused with low potassium containing artificial cerebrospinal fluid. Extracellular field potentials were recorded in CA1 and CA3 regions along with intracellular recordings in CA3 subfield. Reduction of the extracellular potassium concentration [K(+)](o) from 4 to 2 mM caused a transient neuronal hyperpolarisation which was followed by a repolarisation and subsequent depolarisation period. Paroxysmal depolarisation shifts occurred during the transient hyperpolarisation period while epileptic field potentials (EFP) appeared in the late repolarisation or early depolarisation phase. EFP elicited by reduction of [K(+)](o) were neither affected by blockade of N-methyl-D-aspartate (NMDA) glutamate-subreceptor or gamma aminobutyric acid receptor, nor by application of the organic calcium channel blocker nifedipine or the anticonvulsant drugs carbamazepine and valproic acid. Upon application of non-NMDA glutamate-subreceptor blocker the EFP were abolished in all trials, while application of the organic calcium channel blocker verapamil only suppressed the EFP in some cases. The results point to a novel mechanism of epileptogenesis and may provide an in vitro model for the development of new drugs against difficult-to-treat epilepsy.


Assuntos
Epilepsia/metabolismo , Espaço Extracelular/metabolismo , Hipocampo/metabolismo , Potenciais da Membrana/fisiologia , Neurônios/metabolismo , Deficiência de Potássio/metabolismo , Potássio/metabolismo , Animais , Anticonvulsivantes/farmacologia , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio Tipo L/efeitos dos fármacos , Canais de Cálcio Tipo L/metabolismo , Epilepsia/fisiopatologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Espaço Extracelular/efeitos dos fármacos , Antagonistas GABAérgicos/farmacologia , Cobaias , Hipocampo/efeitos dos fármacos , Hipocampo/fisiopatologia , Potenciais da Membrana/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Técnicas de Cultura de Órgãos , Deficiência de Potássio/fisiopatologia , Receptores de GABA/efeitos dos fármacos , Receptores de GABA/metabolismo , Receptores de Glutamato/efeitos dos fármacos , Receptores de Glutamato/metabolismo
10.
Brain Res ; 906(1-2): 74-83, 2001 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-11430863

RESUMO

Cortical spreading depression (CSD) occurrence has been suggested to be associated with seizures, migraine aura, head injury and brain ischemia-infarction. Only few studies identified CSD in human neocortical slices and no comprehensive study so far evaluated this phenomenon in human. Using the neocortical tissue excised for treatment of intractable epilepsy, we aimed to investigate CSD in human. CSD was induced by KCl injection and by modulating T-type Ca(2+) currents in incubated human neocortical tissues in an interphase mode. The DC-fluctuations were recorded by inserting microelectrodes into different cortical layers. Local injection of KCl triggered single CSD that propagated at 3.1+/-0.1 mm/min. Repetitive CSD also occurred spontaneously during long lasting application (5 h) of the T-type Ca(2+) channel blockers amiloride (50 microM) or NiCl(2) (10 microM) which was concomitant with a reversible extracellular potassium increase up to 50 mM. CSD could be blocked by the N-methyl-D-aspartate receptor antagonist 2-amino-5-phosphonovaleric acid in all cases. The results demonstrate that modulation of the Ca(2+) dynamics conditioned human neocortical slices and increased their susceptibility to generate CSD. Furthermore, these data indicate that glutamatergic pathway plays a role in CSD phenomenon in human.


Assuntos
Depressão Alastrante da Atividade Elétrica Cortical/fisiologia , Epilepsia/metabolismo , Neocórtex/metabolismo , Neurônios/metabolismo , Adolescente , Adulto , Amilorida/farmacologia , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio/efeitos dos fármacos , Canais de Cálcio/metabolismo , Sinalização do Cálcio/efeitos dos fármacos , Sinalização do Cálcio/fisiologia , Criança , Depressão Alastrante da Atividade Elétrica Cortical/efeitos dos fármacos , Diuréticos/farmacologia , Epilepsia/induzido quimicamente , Epilepsia/fisiopatologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Feminino , Ácido Glutâmico/metabolismo , Humanos , Masculino , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Pessoa de Meia-Idade , Neocórtex/efeitos dos fármacos , Neocórtex/fisiopatologia , Neurônios/efeitos dos fármacos , Níquel/farmacologia , Potássio/metabolismo , Cloreto de Potássio/farmacologia , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Receptores de N-Metil-D-Aspartato/metabolismo
11.
Epilepsy Res ; 44(2-3): 155-65, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11325571

RESUMO

The antiepileptic effects of the novel antiepileptic drug retigabine (D-23129) [N-(2-amino-4-(4-flurobenzylamino)phenyl) carbamid acid ethyl ester] were tested in neocortical slice preparations (n=23) from 17 patients (age, 3-42 years) who underwent surgery for the treatment of intractable epilepsy. Epileptiform events consisted of spontaneously occurring rhythmic sharp waves, as well as of epileptiform field potentials (EFP) elicited by superfusion with Mg(2+)-free solution without or with addition of 10 micromol/l bicuculline. (1) Spontaneous rhythmic sharp waves (n=6), with retigabine application, the repetition rate was decreased down to 12-47% of initial value (10 micromol/l, n=3) after 180 min or suppressed completely within 12 min (50 micromol/l, n=3). (2) Low Mg(2+) EFP (n=9), with retigabine application, the repetition rate was decreased down to 50 and 65% of initial value (10 micromol/l; n=2) after 180 min or suppressed completely after 9-55 min (10, 50 and 100 micromol/l; n=2 in each case). In one slice only a transient reduction of the repetition rate was seen with 10 micromol/l retigabine. (3) Low Mg(2+) EFP with addition of bicuculline (n=8), with retigabine application, the repetition rate was decreased down to 12-55% of initial value (10 micromol/l; n=4) after 180 min or suppressed completely after 6-30 min (50 and 100 micromol/l; n=2 in each case). The depressive effect of retigabine was reversible in all but one slice. The results show a clear antiepileptic effect of retigabine in human neocortical slices on spontaneously occurring rhythmic sharp waves and different types of induced seizure activity.


Assuntos
Potenciais de Ação/efeitos dos fármacos , Anticonvulsivantes/farmacologia , Carbamatos/farmacologia , Neocórtex/efeitos dos fármacos , Fenilenodiaminas/farmacologia , Potenciais de Ação/fisiologia , Adolescente , Adulto , Anticonvulsivantes/uso terapêutico , Bicuculina/farmacologia , Carbamatos/uso terapêutico , Criança , Pré-Escolar , Epilepsias Parciais/tratamento farmacológico , Epilepsias Parciais/patologia , Feminino , Antagonistas GABAérgicos/farmacologia , Humanos , Magnésio/farmacologia , Masculino , Neocórtex/fisiologia , Fenilenodiaminas/uso terapêutico
12.
Eur J Neurosci ; 13(3): 639-40, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11168573

RESUMO

The increase in the extracellular potassium concentration ([K(+)](o)) is a well-established model of epilepsy (the so-called high potassium model). Therefore, it is generally accepted that for the prevention of abnormal excitability and seizure generation, increases of [K(+)](o) must be avoided. In this paper, however, we show that on the contrary, a reduction of [K(+)](o) also elicits epileptic activity in brain slices of man.


Assuntos
Epilepsia Parcial Complexa/fisiopatologia , Epilepsia Generalizada/fisiopatologia , Neocórtex/fisiopatologia , Potássio/farmacologia , Adolescente , Adulto , Criança , Pré-Escolar , Epilepsia Parcial Complexa/induzido quimicamente , Epilepsia Parcial Complexa/metabolismo , Epilepsia Generalizada/induzido quimicamente , Epilepsia Generalizada/metabolismo , Espaço Extracelular/metabolismo , Feminino , Humanos , Técnicas In Vitro , Lactente , Masculino , Pessoa de Meia-Idade , Neocórtex/metabolismo
13.
Neuroscience ; 100(3): 445-52, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11098107

RESUMO

The antiepileptic effect of the dihydropyridine calcium channel blocker nifedipine was tested in neocortical slice preparations (n=27) from patients ranging in age from four to 46 years (mean=25) who underwent surgery for the treatment of intractable epilepsy. Epileptiform events consisted of spontaneously occurring rhythmic sharp waves as well as of untriggered epileptiform field potentials induced by omission of Mg(2+) from the superfusate, or epileptiform field potentials elicited by application of bicuculline and triggered by single electrical stimuli. (1) Spontaneous rhythmic sharp waves (n=6): with nifedipine (40micromol/l), the repetition rate was decreased down to 30% of initial value, whereas the area under the field potential remained nearly unchanged. (2) Untriggered low Mg(2+) epileptiform field potentials (n=6): with nifedipine (40micromol/l) the area under the field potentials was reduced while the action on the repetition rate was ambiguous. (3) Triggered bicuculline epileptiform field potentials (n=15): with nifedipine (40micromol/l; n=4), no antiepileptic effect was found. There was, however, a marked increase in the area under the epileptiform field potentials. The area under the field potentials was reduced only at a dosage of 60micromol/l (n=11). This effect was stronger when nifedipine was applied with a K(+) concentration raised from 4 to 8mmol/l. The results show that the calcium channel blocker nifedipine is able to reduce differential epileptiform discharges in human neocortical tissue. These observations are in line with previous findings, suggesting that calcium flux into neurons is involved in epileptogenesis. The present results therefore support the idea that some organic calcium antagonists may be useful in human epilepsy therapy, although the etiology of epileptic seizures seems to be a critical factor for the efficacy of the drug.


Assuntos
Bloqueadores dos Canais de Cálcio/farmacologia , Neocórtex/fisiologia , Nifedipino/farmacologia , Periodicidade , Adolescente , Bicuculina , Criança , Pré-Escolar , Convulsivantes , Relação Dose-Resposta a Droga , Eletrofisiologia , Epilepsia/induzido quimicamente , Epilepsia/fisiopatologia , Humanos , Técnicas In Vitro , Lactente , Recém-Nascido , Magnésio/administração & dosagem
14.
J Neurophysiol ; 84(4): 2161-5, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11024103

RESUMO

Functional changes in neuronal circuitry reflected in spontaneously occurring synchronous sharp field potentials (SSFP) have been reported to occur in human brain suffering from chronic epileptogenicity but not in primary nonepileptic tissue from peritumoral resectates. Voltage sensitive dyes and fast imaging were used to visualize spontaneously occurring rhythmic depolarizations correlated to SSFP in chronically epileptic human neocortical slices obtained during epilepsy surgery. Localized and spatially inhomogeneous neuronal depolarizations were found to underlie spontaneous SSFP, which remained unchanged and spatially restricted to foci <750 micrometer diam even under epileptogenic (low-Mg(2+)) conditions. In cases where ictaform paroxysmal activity occurred in low-Mg(2+) medium, neuronal depolarizations were wide-spread but still spatially inhomogeneous, and the events were preferentially initiated at distinct foci. The findings suggest that small neuronal networks are able to establish and maintain synchronous rhythmic and epileptiform activity.


Assuntos
Epilepsia/fisiopatologia , Neocórtex/fisiopatologia , Neurônios/fisiologia , Potenciais de Ação , Doença Crônica , Relação Dose-Resposta a Droga , Epilepsia/patologia , Humanos , Técnicas In Vitro , Magnésio/administração & dosagem , Magnésio/farmacologia , Neocórtex/efeitos dos fármacos , Neocórtex/patologia , Rede Nervosa/fisiopatologia , Óptica e Fotônica , Periodicidade
15.
J Neurosci Methods ; 102(1): 1-9, 2000 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-11000406

RESUMO

Living brain slices are usually cut with razor blades, which compress a ca. 50-microm-thick layer of tissue. This results in cell debris and lesioned cells which, e.g. form diffusion barriers between the bath and living neurons underneath, thereby prolonging response times of neurons to drugs in the bath saline and impeding the experimental access to intact neurons. To avoid such drawbacks, a macromingotome was developed which cuts nervous tissue with water jets. Physiological saline under pressures of 100-1800 bar was ejected through nozzles of 35-100 microm to cut 300-500-microm-thick hippocampal slices. Systematic variations of pressure and nozzle diameter revealed best results at 400-600 bar and with nozzle diameters of 60-80 microm. Under these conditions, intact CA1- and CA3-neurons as well as granule cells were detected with infrared microscopy at less than 10 microm underneath the surface of the slice. Superficial neurons with intact fine structures were also seen when the slices were studied by light-microscopy. Intra- and extracellular recordings from superficial neurons showed normal membrane- and full action potentials and the development of stable epileptiform discharges in 0 Mg(2+)-saline. These results indicate that the macromingotome offers an alternative way of cutting slices which may facilitate electrophysiological/neuropharmacological or fluorometric studies on superficial neurons.


Assuntos
Técnicas de Cultura/métodos , Hipocampo/citologia , Microtomia/instrumentação , Microtomia/métodos , Pressão , Água , Potenciais de Ação/fisiologia , Animais , Cobaias , Hipocampo/fisiologia , Neurônios/citologia , Neurônios/fisiologia , Ratos
16.
Neurobiol Dis ; 7(4): 471-82, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10964616

RESUMO

Organic calcium channel antagonists block epileptiform activity in adult tissue, suggesting an essential role of L-type channels in epileptogenesis in the mature CNS. By contrast, this remains doubtful for neonatal tissue, as the density of calcium channels changes markedly with ontogenesis. The paper addresses this question by exploring the antiepileptic efficacy of the L-type calcium channel blockers verapamil and nifedipine in low-Mg(2+)-epilepsy in rat hippocampal slices of different postnatal (PN) ages. Field (CA3, CA1) and membrane potentials (CA3) were recorded. Washout of Mg(2+) induced epileptiform potentials, which were blocked age-dependently: Verapamil suppressed activity in all preparations of PN1-5 and PN13-30+, but only in 70% of PN6-12. Nifedipine depressed activity in >75% of slices of PN13-30+, but only in 33% of PN1-12. The findings indicate a role of L-type calcium channels in epileptogenesis from PN13 onwards, with phenylalkylamine-sensitive calcium channels also being involved during PN1-5.


Assuntos
Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio Tipo L/efeitos dos fármacos , Epilepsia , Potenciais da Membrana/efeitos dos fármacos , Nifedipino/farmacologia , Verapamil/farmacologia , Fatores Etários , Animais , Animais Recém-Nascidos , Bloqueadores dos Canais de Cálcio/uso terapêutico , Canais de Cálcio Tipo L/fisiologia , Epilepsia/tratamento farmacológico , Hipocampo/efeitos dos fármacos , Hipocampo/fisiologia , Potenciais da Membrana/fisiologia , Nifedipino/uso terapêutico , Células Piramidais/efeitos dos fármacos , Células Piramidais/fisiologia , Ratos , Verapamil/uso terapêutico
17.
Neuroscience ; 95(1): 63-72, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10619462

RESUMO

The aim of the present investigation was to compare the antiepileptic efficacy of the specific L-type calcium channel blocker nifedipine in hippocampal and neocortical slice preparations in the Mg2+-free model of epilepsy. The main findings were as follows. (1) In hippocampal slices, in general, nifedipine (20-80 micromol/l) exerted a suppressive effect both on repetition rate and on area under epileptiform field potentials. This effect was clearly dose dependent. In the majority of cases, this suppression was preceded by an increase, which was transient in nature. Only in the lowest concentration (20 micromol/l) used, in normal K+, instead of a depression, a persistent increase occurred. (2) In neocortical slices, in the majority of experiments, nifedipine (20-80 micromol/l) showed a depressive action only on the area under the epileptiform field potentials. The depressive effect of nifedipine on the area was dose dependent, although to a lesser extent than in the hippocampus. In nearly half of the slices this suppression was preceded by a transient increase. By contrast, the repetition rate of epileptiform field potentials increased transiently in about 20% of the slices followed by a decrease. In the remaining 80% of the slices the repetition rate increased persistently. (3) An elevation of the K+ concentration accentuated the depressive actions of nifedipine only in the hippocampus. In contrast to elevated K+, in both the hippocampus and the neocortex, epileptiform field potentials were not suppressed in all experiments in normal K+. (4) The reversibility of the depressive effects of nifedipine was differential in the two tissue types. In the hippocampus, after suppression of epileptiform field potentials they reappeared in the overwhelming majority of slices. In the neocortex, this was the case in only one experiment. These findings may indicate the existence of L-type calcium channels with a differential functional significance for epileptogenesis and/or the existence of different forms of L-type channels in hippocampal and neocortical tissue. As a whole, the differential effects of L-type calcium channel blockade in the hippocampus and neocortex point to differences in the network properties of the two tissue types.


Assuntos
Canais de Cálcio Tipo L/fisiologia , Epilepsia/fisiopatologia , Hipocampo/fisiopatologia , Neocórtex/fisiopatologia , Animais , Bloqueadores dos Canais de Cálcio/farmacologia , Relação Dose-Resposta a Droga , Feminino , Cobaias , Hipocampo/efeitos dos fármacos , Técnicas In Vitro , Masculino , Neocórtex/efeitos dos fármacos , Nifedipino/farmacologia
18.
Cephalalgia ; 20(8): 740-7, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11167905

RESUMO

Spreading depressions (SD) occur in association with ischaemia, epilepsy and migraine. Intracellular calcium oscillations have been suggested to be involved in the generation and propagation of SD. The present study was performed to study the mechanism of conditioning guinea pig hippocampal slices by the T-type calcium channel blockers NiCl2 and amiloride. SD-like fluctuations of DC potential were recorded by inserting microelectrodes into the CA1 and CA3 regions. The SD occurrence was significantly greater with 10 micromol/l NiCl2 as well as with 25 and 50 micromol/l amiloride than with other concentrations of these substances. The concentration response curve was inversely U-shaped with the maximum repetition rates of SDs being achieved at 10 micromol/l NiCl2 as well as at 25 and 50 micromol/l amiloride. SD occurrence could be completely blocked by the NMDA antagonist APV (10 micromol/l) in all cases. These data demonstrate that modulation of the Ca2+ dynamics conditioned guinea pig hippocampal slices and increased their susceptibility to generate SD.


Assuntos
Amilorida/farmacologia , Bloqueadores dos Canais de Cálcio/farmacologia , Depressão Alastrante da Atividade Elétrica Cortical/fisiologia , Hipocampo/efeitos dos fármacos , Hipocampo/fisiologia , Níquel/farmacologia , Valina/análogos & derivados , Animais , Canais de Cálcio Tipo T/efeitos dos fármacos , Depressão Alastrante da Atividade Elétrica Cortical/efeitos dos fármacos , Relação Dose-Resposta a Droga , Eletrofisiologia , Cobaias , Técnicas In Vitro , N-Metilaspartato/antagonistas & inibidores , Valina/farmacologia
19.
Epilepsy Res ; 32(1-2): 224-32, 1998 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9761323

RESUMO

The spatio-temporal distribution of epileptiform activity was investigated in slices from human temporal neocortex resected during epilepsy surgery. Activity was recorded by use of a voltage-sensitive dye and an optical recording system. Epileptiform activity was induced with 10 microM bicuculline and electrical stimulation of layer I. In 10 slices from six patients investigated, epileptiform activity spread across most of the slice. Largest amplitudes were located in layer II/III. Epileptiform activity was characterized by long-lasting potentials with slow rising phases and a low velocity of spread in the horizontal direction (0.044 m/s). This spatio-temporal pattern of epileptiform activity in human slices was similar to that found previously in neocortical slices from guinea pigs with bicuculline. In four of nine human slices investigated under control bath conditions (in non-epileptogenic medium), the spatio-temporal activity patterns were similar to those of guinea pigs in non-epileptogenic medium. In the remaining five human slices, however, the spread in the horizontal direction was significantly larger (4188 microm) in non-epileptogenic medium than that found in slices from guinea pigs (2171 microm). Activity in human slices showing such 'wide spread' in control bath conditions occasionally had characteristic features of epileptiform activity. Further work will have to clarify whether these epileptiform features reflect intrinsic epileptiform properties in human tissue slices.


Assuntos
Mapeamento Encefálico , Epilepsia do Lobo Temporal/fisiopatologia , Potenciais Evocados/fisiologia , Neocórtex/fisiopatologia , Neurônios/fisiologia , Animais , Bicuculina/farmacologia , Corantes , Estimulação Elétrica , Epilepsia do Lobo Temporal/cirurgia , Potenciais Evocados/efeitos dos fármacos , Cobaias , Humanos , Técnicas In Vitro , Neocórtex/efeitos dos fármacos , Neocórtex/fisiologia , Neurônios/efeitos dos fármacos
20.
MCN Am J Matern Child Nurs ; 23(5): 262-5, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9747089

RESUMO

In response to several women who presented with postpartum depression in 1 year, a group of nurses developed a task force made up of hospital nurses, obstetricians, psychiatrists, pediatricians, family practitioners, lactation specialists, home care nurses, and mental health counselors. The purposes of this task force were to educate health care professionals about postpartum depression, to help identify women who might be affected, and to develop interventions for adjusting to parenthood. This article details the evolution of that task force, and how it has assisted not only the women but also the health care providers involved.


Assuntos
Enfermagem em Saúde Comunitária , Depressão Pós-Parto/prevenção & controle , Educação em Saúde/organização & administração , Equipe de Assistência ao Paciente , Participação da Comunidade , Depressão Pós-Parto/enfermagem , Feminino , Humanos , Idaho
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