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1.
J Child Orthop ; 12(3): 209-217, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29951119

RESUMO

PURPOSE: Paediatric trigger finger (PTF) is a rare condition as seen by the lack of studies published about paediatric populations. Due to this general lack of information, the steps to employ to correct this disorder, whether surgically or non-surgically, have not yet reached consensus status. The objective of this study is to review the published literature regarding treatment options for PTF in order to develop a proposed step-wise treatment algorithm for children presenting with trigger finger. METHODS: A systematic review of the literature was conducted on PubMed to locate English language studies reporting on treatment interventions of PTF. Data was collected on number of patients/fingers seen in the study, the category of the fingers involved, the number of patients/fingers undergoing each intervention and reported outcomes. RESULTS: Seven articles reporting on 118 trigger fingers were identified. In all, 64 fingers were treated non-surgically, with 57.8% (37/64) resolving. In all, 54 fingers were initially surgically treated, with 87% (47/54) resolving. In total, 34 fingers did not have resolution of symptoms following primary treatment, and 27 fingers received follow-up treatment, with 92.6% (25/27) resolving. Overall, 92.4% (109/118) of fingers achieved resolution of symptoms after all treatments were completed. CONCLUSION: Limitations for this study included few prospective studies and small sample sizes. This is likely due to the rarity of PTF. This review of the literature indicated that a step-wise approach, including non-operative and surgical techniques, should be employed in the management of PTF. LEVEL OF EVIDENCE III: This work meets the requirements of the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-Analyses).

2.
Orthop Traumatol Surg Res ; 100(1): 153-7, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24332925

RESUMO

BACKGROUND: Segmental tissue loss in the lateral meniscus is associated with pain and increased risk of osteoarthritis even when indications have been carefully considered. HYPOTHESIS: Repairing the defect using a novel biodegradable scaffold will reduce pain and restore the knee function. METHODS: In this prospective multicenter study, a total of 54 patients (37 males/17 females; mean age: 28 years [16-50]) were enrolled. All patients presented with postmeniscectomy syndrome and segmental lateral meniscus loss, and were treated with a polyurethane biodegradable scaffold (Actifit(®), Orteq) implanted arthroscopically. Clinical outcomes were assessed at 6, 12 and 24 months using Visual Analogue Scale (VAS), International Knee Documentation Committee Score (IKDC) and Knee Injury and Osteoarthritis Outcome Score (KOOS). RESULTS: VAS decreased from 5.5 at baseline to 3.6 at 6 months, 3.4 at 12 months and 2.9 at 24 months. IKDC improved from 47.0 at baseline to 60.2, 67.0 and 67.0 at 6, 12 and 24 months. All KOOS subscores improved between baseline and 24 months. DISCUSSION: Clinical results of this study demonstrate clinically and statistically significant improvements of pain and function scores (VAS, IKDC, and all KOOS subscales except sport), at the 6 months follow-up and on all clinical outcomes at the 2-year follow-up. The Actifit(®) scaffold is safe and effective in treating lateral meniscus defects. LEVEL OF EVIDENCE IV: continuous prospective multicenter study.


Assuntos
Meniscos Tibiais/cirurgia , Poliuretanos , Alicerces Teciduais , Adolescente , Adulto , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Procedimentos Ortopédicos/métodos , Estudos Prospectivos , Desenho de Prótese , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
3.
Neuroscience ; 162(4): 989-1000, 2009 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-19446607

RESUMO

We investigated the contribution of large conductance calcium-activated potassium (BK) channels to spontaneous activity of cerebellar Purkinje neurons in mice and rats. In Purkinje neurons which fire tonically, block of BK channels increased the firing rate and caused the neurons to fire irregularly. In Purkinje neurons which exhibited a trimodal pattern of activity, present primarily in mature animals, block of BK channels had little effect on firing rate or regularity but shortened the single cycle duration of the trimodal pattern. The contribution of BK channels to the action potential waveform was also examined. BK channels contributed a brief afterhyperpolarization (AHP) of approximately 3 mV which followed each action potential, but made little contribution to action potential repolarization. The amplitude of the BK-dependent AHP did not change with age although there was an increase in the total AHP. The difference in the contribution of BK channels to the firing rate among the two populations of Purkinje neurons was the consequence of the decrease in the fractional contribution of BK channels to the AHP. We also found that block of BK channels increases intracellular calcium concentration during spontaneous firing. Thus, although BK channels do not affect action potential repolarization, they nevertheless control calcium entry with each action potential by contributing to the AHP.


Assuntos
Cálcio/metabolismo , Canais de Potássio Ativados por Cálcio de Condutância Alta/fisiologia , Células de Purkinje/fisiologia , Potenciais de Ação , Envelhecimento , Animais , Bloqueadores dos Canais de Cálcio/farmacologia , Espaço Intracelular/metabolismo , Camundongos , Periodicidade , Células de Purkinje/efeitos dos fármacos , Ratos , Ratos Wistar , Sinapses/fisiologia
4.
Osteoarthritis Cartilage ; 15(1): 1-8, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16891130

RESUMO

OBJECTIVE: Chondrocytes are highly sensitive to variations in extracellular glucose and oxygen levels in the extracellular matrix. As such, they must possess a number of mechanisms to detect and respond to alterations in the metabolic state of cartilage. In other organs such as the pancreas, heart and brain, such detection is partly mediated by a family of potassium channels known as K(ATP) (adenosine 5'-triphosphate-sensitive potassium) channels. Here we investigate whether chondrocytes too express functional K(ATP) channels, which might, potentially, serve to couple metabolic state with cell activity. METHODS: Immunohistochemistry was used to explore K(ATP) channel expression in equine and human chondrocytes. Biophysical properties of equine chondrocyte K(ATP) channels were investigated with patch-clamp electrophysiology. RESULTS: Polyclonal antibodies directed against the K(ATP) Kir6.1 subunit revealed high levels of expression in human and equine chondrocytes mainly in superficial and middle zones of normal cartilage. Kir6.1 was also detected in superficial chondrocytes in osteoarthritic (OA) cartilage. In single-channel electrophysiological studies of equine chondrocytes, we found K(ATP) channels to have a maximum unitary conductance of 47 +/- 9 pS (n=5) and a density of expression comparable to that seen in excitable cells. CONCLUSION: We have shown, for the first time, functional K(ATP) channels in chondrocytes. This suggests that K(ATP) channels are involved in coupling metabolic and electrical activities in chondrocytes through sensing of extracellular glucose and intracellular adenosine triphosphate (ATP) levels. Altered K(ATP) channel expression in OA chondrocytes may result in impaired intracellular ATP sensing and optimal metabolic regulation.


Assuntos
Cartilagem Articular/metabolismo , Condrócitos/metabolismo , Osteoartrite/fisiopatologia , Canais de Potássio Corretores do Fluxo de Internalização/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Cavalos , Humanos , Imuno-Histoquímica , Potenciais da Membrana/fisiologia , Técnicas de Patch-Clamp , Canais de Potássio Corretores do Fluxo de Internalização/fisiologia
5.
Br J Pharmacol ; 149(5): 600-7, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17001301

RESUMO

BACKGROUND AND PURPOSE: alpha-tetrahydrodeoxycorticosterone (THDOC) is an endogenous neuroactive steroid which increases in plasma and brain concentration during stress. It has both positive and negative modulatory effects on GABA activated GABAA currents, dependent upon the dose. We investigated the effects of THDOC on spinally-projecting "pre-sympathetic" neurones in the parvocellular subnucleus of the hypothalamic paraventricular nucleus (PVN), to determine whether it activates or inhibits these neurones, and by what mechanism. EXPERIMENTAL APPROACH: Rat spinally-projecting (parvocellular) PVN neurones were identified by retrograde labelling and the action of THDOC investigated with three modes of patch-clamp: cell-attached action current, whole-cell voltage-clamp and cell-attached single-channel recording. KEY RESULTS: In cell-attached patch mode, parvocellular neurones fired action potentials spontaneously with an average frequency of 3.6 +/- 1.1 Hz. Bath application of THDOC reduced this with an EC50 of 67 nM (95% confidence limits: 54 to 84 nM), Hill coefficient 0.8 +/- 0.04, n = 5. In whole-cell patch-clamp mode, pressure ejection of GABA evoked inward currents. These were clearly GABAA currents, since they were inhibited by the GABAA receptor antagonist bicuculline, and reversed near the chloride equilibrium potential. THDOC significantly potentiated GABAA currents (1 microM THDOC: 148 +/- 15% of control, n = 5, p < or = 0.05, ANOVA). Single-channel analysis showed no differences in conductance or corrected mean open times in the presence of 1 microM THDOC. CONCLUSIONS AND IMPLICATIONS: THDOC inhibited parvocellular neuronal activity without showing any evidence of the bidirectional activity demonstrated previously with cultured hypothalamic neurones. Our data are consistent with the hypothesis that THDOC acts by potentiating the post-synaptic activity of endogenously released GABA.


Assuntos
Potenciais de Ação/efeitos dos fármacos , Desoxicorticosterona/análogos & derivados , Neurônios/efeitos dos fármacos , Animais , Bicuculina/farmacologia , Desoxicorticosterona/farmacologia , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Feminino , Antagonistas GABAérgicos/farmacologia , Hipotálamo/citologia , Hipotálamo/efeitos dos fármacos , Hipotálamo/fisiologia , Ativação do Canal Iônico/efeitos dos fármacos , Ativação do Canal Iônico/fisiologia , Cinética , Masculino , Neurônios/citologia , Neurônios/fisiologia , Núcleo Hipotalâmico Paraventricular/citologia , Núcleo Hipotalâmico Paraventricular/efeitos dos fármacos , Núcleo Hipotalâmico Paraventricular/fisiologia , Técnicas de Patch-Clamp/métodos , Ratos , Ratos Wistar , Receptores de GABA-A/fisiologia , Sistema Nervoso Simpático/citologia , Sistema Nervoso Simpático/efeitos dos fármacos , Sistema Nervoso Simpático/fisiologia , Transmissão Sináptica/efeitos dos fármacos , Ácido gama-Aminobutírico/metabolismo , Ácido gama-Aminobutírico/farmacologia
6.
J Pharmacol Exp Ther ; 314(3): 1274-89, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15951399

RESUMO

Recent data has suggested that the 5-hydroxytryptamine (5-HT)(1A) receptor is involved in cognitive processing. A novel 5-HT(1A) receptor antagonist, 4-cyano-N-{2R-[4-(2,3-dihydrobenzo[1,4]-dioxin-5-yl)-piperazin-1-yl]-propyl}-N-pyridin-2-yl-benzamide HCl (lecozotan), which has been characterized in multiple in vitro and in vivo pharmacological assays as a drug to treat cognitive dysfunction, is reported. In vitro binding and intrinsic activity determinations demonstrated that lecozotan is a potent and selective 5-HT(1A) receptor antagonist. Using in vivo microdialysis, lecozotan (0.3 mg/kg s.c.) antagonized the decrease in hippocampal extracellular 5-HT induced by a challenge dose (0.3 mg/kg s.c.) of 8-hydroxy-2-dipropylaminotetralin (8-OH-DPAT) and had no effects alone at doses 10-fold higher. Lecozotan significantly potentiated the potassium chloride-stimulated release of glutamate and acetylcholine in the dentate gyrus of the hippocampus. Chronic administration of lecozotan did not induce 5-HT(1A) receptor tolerance or desensitization in a behavioral model indicative of 5-HT(1A) receptor function. In drug discrimination studies, lecozotan (0.01-1 mg/kg i.m.) did not substitute for 8-OH-DPAT and produced a dose-related blockade of the 5-HT(1A) agonist discriminative stimulus cue. In aged rhesus monkeys, lecozotan produced a significant improvement in task performance efficiency at an optimal dose (1 mg/kg p.o.). Learning deficits induced by the glutamatergic antagonist MK-801 [(-)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate] (assessed by perceptually complex and visual spatial discrimination) and by specific cholinergic lesions of the hippocampus (assessed by visual spatial discrimination) were reversed by lecozotan (2 mg/kg i.m.) in marmosets. The heterosynaptic nature of the effects of lecozotan imbues this compound with a novel mechanism of action directed at the biochemical pathologies underlying cognitive loss in Alzheimer's disease.


Assuntos
Acetilcolina/metabolismo , Cognição/efeitos dos fármacos , Dioxanos/farmacologia , Ácido Glutâmico/metabolismo , Hipocampo/efeitos dos fármacos , Piperazinas/farmacologia , Antagonistas do Receptor 5-HT1 de Serotonina , Antagonistas da Serotonina/farmacologia , 8-Hidroxi-2-(di-n-propilamino)tetralina/farmacologia , Doença de Alzheimer/tratamento farmacológico , Animais , Callithrix , Columbidae , Aprendizagem por Discriminação/efeitos dos fármacos , Feminino , Gânglios Espinais/efeitos dos fármacos , Hipocampo/metabolismo , Macaca mulatta , Masculino , Metoxidimetiltriptaminas/antagonistas & inibidores , Microdiálise , Ratos , Ratos Sprague-Dawley , Saimiri
7.
Am J Physiol Regul Integr Comp Physiol ; 289(1): R172-80, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15802557

RESUMO

In this comparative study, we have established in vitro models of equine and elephant articular chondrocytes, examined their basic morphology, and characterized the biophysical properties of their primary voltage-gated potassium channel (Kv) currents. Using whole cell patch-clamp electrophysiological recording from first-expansion and first-passage cells, we measured a maximum Kv conductance of 0.15 +/- 0.04 pS/pF (n = 10) in equine chondrocytes, whereas that in elephant chondrocytes was significantly larger (0.8 +/- 0.4 pS/pF, n = 4, P

Assuntos
Cartilagem Articular/metabolismo , Condrócitos/metabolismo , Elefantes/metabolismo , Cavalos/metabolismo , Canais de Potássio de Abertura Dependente da Tensão da Membrana/fisiologia , 4-Aminopiridina/farmacologia , Animais , Cartilagem Articular/citologia , Venenos Elapídicos/farmacologia , Eletrofisiologia , Imuno-Histoquímica , Cinética , Modelos Biológicos , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio de Abertura Dependente da Tensão da Membrana/efeitos dos fármacos , Canais de Potássio de Abertura Dependente da Tensão da Membrana/metabolismo , Tetraetilamônio/farmacologia
8.
Plant Dis ; 86(6): 676-681, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30823244

RESUMO

Polymerase chain reaction (PCR) assays were used to detect phytoplasmas in Canary Island date (Phoenix canariensis) palms displaying symptoms similar to lethal yellowing (LY) disease in Corpus Christi, TX. An rDNA product (1.8 kb) was amplified consistently from 10 of 11 palms by PCR employing phytoplasma universal rRNA primer pair P1/P7. Also, AluI endonu-clease digests and sequencing of P1/P7 products revealed that nontarget Bacillus megaterium-related rDNA sequences of similar size were co-amplified along with phytoplasma rDNA from 10 palms. A 1,402-bp product was obtained from all 11 symptomatic palms when initial P1/P7 products were reamplified by PCR employing nested LY phytoplasma group-specific 16S rRNA primer pair LY16Sf/LY16Sr. Restriction fragment length polymorphism (RFLP) analysis of nested PCR products revealed that palm-infecting phytoplasmas were uniform and most similar to strains composing the coconut lethal yellowing phytoplasma (16SrIV) group. Sequence analysis of 16S rDNA determined the Texas Phoenix palm decline (TPD) phytoplasma to be phylogenetically closest to the Carludovica palmata leaf yellowing (CPY) phytoplasma. rDNA profiles of strains TPD and CPY obtained with AluI were co-identical and distinct from other known 16SrIV group phytoplasmas. On this basis, both strains were classified as members of a new subgroup, 16SrIV-D.

9.
Science ; 292(5520): 1339-43, 2001 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-11359003

RESUMO

The gas activity of comet C/1999 S4 (LINEAR) was monitored at radio wavelengths during its disruption. A runaway fragmentation of the nucleus may have begun around 18 July 2000 and proceeded until 23 July. The mass in small icy debris (

10.
J Gen Physiol ; 115(3): 339-46, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10694261

RESUMO

Cerebellar Purkinje neurons demonstrate a form of synaptic plasticity that, in acutely prepared brain slices, has been shown to require calcium release from the intracellular calcium stores through inositol trisphosphate (InsP(3)) receptors. Similar studies performed in cultured Purkinje cells, however, find little evidence for the involvement of InsP(3) receptors. To address this discrepancy, the properties of InsP(3)- and caffeine-evoked calcium release in cultured Purkinje cells were directly examined. Photorelease of InsP(3) (up to 100 microM) from its photolabile caged analogue produced no change in calcium levels in 70% of cultured Purkinje cells. In the few cells where a calcium increase was detected, the response was very small and slow to peak. In contrast, the same concentration of InsP(3) resulted in large and rapidly rising calcium responses in all acutely dissociated Purkinje cells tested. Similar to InsP(3), caffeine also had little effect on calcium levels in cultured Purkinje cells, yet evoked large calcium transients in all acutely dissociated Purkinje cells tested. The results demonstrate that calcium release from intracellular calcium stores is severely impaired in Purkinje cells when they are maintained in culture. Our findings suggest that cultured Purkinje cells are an unfaithful experimental model for the study of the role of calcium release in the induction of cerebellar long term depression.


Assuntos
Cálcio/metabolismo , Células de Purkinje/citologia , Células de Purkinje/metabolismo , Animais , Cafeína/farmacologia , Canais de Cálcio/fisiologia , Células Cultivadas , Estimulantes do Sistema Nervoso Central/farmacologia , Inositol 1,4,5-Trifosfato/farmacologia , Receptores de Inositol 1,4,5-Trifosfato , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Camundongos , Camundongos Endogâmicos , Inibição Neural/fisiologia , Plasticidade Neuronal/fisiologia , Células de Purkinje/química , Receptores Citoplasmáticos e Nucleares/fisiologia , Canal de Liberação de Cálcio do Receptor de Rianodina/fisiologia , Sistemas do Segundo Mensageiro/fisiologia
11.
Br J Pharmacol ; 131(8): 1716-22, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11139451

RESUMO

The pharmacological characterization of a 5-HT receptor-mediated contractile response in the mouse isolated ileum is described. In the presence of methysergide (1 microM), 5-hydroxytryptamine (5-HT, 0.3 - 100 microM) produced phasic concentration-dependent contractions of segments of the mouse isolated ileum with a pEC(50) value of 5.47+/-0.09. The 5-HT(3) receptor selective agonists m-chlorophenylbiguanide (0.3 - 100 microM, pEC(50) 5.81+/-0.04), 1-phenylbiguanide (3 - 100 microM, pEC(50) 5.05+/-0.06) and 2-methyl-5-HT (3 - 100 microM, pEC(50) 5.00+/-0.07) acted as full agonists to induce contractile responses. 5-methoxytryptamine (0.1 - 100 microM), RS 67506 (0.1 - 100 microM) and alpha-methyl-5-HT (0.1 - 100 microM) failed to mimic the 5-HT responses. The contractile response to 5-HT was not antagonized by either 5-HT(2) receptor antagonists ritanserin (0.1 microM) or ketanserin (1 microM) nor the 5-HT(4) receptor antagonist SB 204070 (0.1 microM). The 5-HT(3) receptor selective antagonists granisetron (0.3 - 1 nM), tropisetron (1 - 10 nM), ondansetron (10 nM - 1 microM) and MDL 72222 (10 nM - 1 microM) caused rightward displacement of the concentration-response curves to 5-HT. The lower concentrations of the antagonists caused approximate parallel rightward shifts of the concentration-response curves to 5-HT with apparent pK(B) values for granisetron (9.70+/-0. 39), tropisetron (9.18+/-0.20), ondansetron (8.84+/-0.24) and MDL 72222 (8.65+/-0.35). But higher concentrations of antagonists resulted in a progressive reduction in the maximum responses. The contractile response to 5-HT was abolished by tetrodotoxin (0.3 microM); atropine (0.1 and 1 microM) decreased the maximum response of the 5-HT concentration-response curve by approximately 65%. It is concluded that a neuronally located 5-HT(3) receptor mediates a contractile response to 5-HT in the mouse ileum. The 5-HT(3) receptor in the mouse ileum has a different pharmacological profile to that reported for the guinea-pig ileum.


Assuntos
Íleo/fisiologia , Contração Muscular/fisiologia , Receptores de Serotonina/fisiologia , Animais , Atropina/farmacologia , Dioxanos/farmacologia , Relação Dose-Resposta a Droga , Feminino , Granisetron/farmacologia , Íleo/efeitos dos fármacos , Técnicas In Vitro , Indóis/farmacologia , Ketanserina/farmacologia , Masculino , Camundongos , Contração Muscular/efeitos dos fármacos , Ondansetron/farmacologia , Piperidinas/farmacologia , Receptores de Serotonina/efeitos dos fármacos , Ritanserina/farmacologia , Serotonina/farmacologia , Antagonistas da Serotonina/farmacologia , Agonistas do Receptor de Serotonina/farmacologia , Tetrodotoxina/farmacologia , Tropanos/farmacologia , Tropizetrona
12.
J Neurosci ; 19(23): 10201-12, 1999 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-10575017

RESUMO

We have used the squid giant synapse to determine whether clathrin assembly by AP180 is important for synaptic vesicle endocytosis. The squid homolog of AP180 encodes a 751 amino acid protein with 40% sequence identity to mouse AP180. Alignment of squid AP180 with other AP180 homologs shows that amino acid identity was highest in the N-terminal inositide-binding domain of the protein and weakest in the C-terminal clathrin assembly domain. Recombinant squid AP180 was able to assemble clathrin in vitro, suggesting a conserved three-dimensional structure that mediates clathrin assembly despite the divergent primary sequence of the C-terminal domain. Microinjection of the C-terminal domains of either mouse or squid AP180 into the giant presynaptic terminal of squid enhanced synaptic transmission. Conversely, a peptide from the C-terminal domain of squid AP180 that inhibited clathrin assembly in vitro completely blocked synaptic transmission when it was injected into the giant presynaptic terminal. This inhibitory effect occurred over a time scale of minutes when the synapse was stimulated at low (0.03 Hz), physiological rates. Electron microscopic analysis revealed several structural changes consistent with the inhibition of synaptic vesicle endocytosis; peptide-injected terminals had far fewer synaptic vesicles, were depleted of coated vesicles, and had a larger plasma membrane perimeter than terminals injected with control solutions. In addition, the remaining synaptic vesicles were significantly larger in diameter. We conclude that the clathrin assembly domain of AP180 is important for synaptic vesicle recycling at physiological rates of activity and that assembly of clathrin by AP180 is necessary for maintaining a pool of releasable synaptic vesicles.


Assuntos
Endocitose/fisiologia , Proteínas Monoméricas de Montagem de Clatrina , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/fisiologia , Fosfoproteínas/genética , Fosfoproteínas/fisiologia , Vesículas Sinápticas/fisiologia , Proteínas Adaptadoras de Transporte Vesicular , Sequência de Aminoácidos/genética , Animais , Clonagem Molecular , Decapodiformes , Dados de Sequência Molecular , Homologia de Sequência de Aminoácidos , Transmissão Sináptica/fisiologia
13.
Neuroreport ; 9(15): 3391-5, 1998 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-9855287

RESUMO

Weaver mice carry a mutation in the pore domain of the Girk2 (Kcnj6) gene. The mutation causes GIRK2 containing channels to lose ion selectivity and to become constitutively active. It is not known how this alteration in ion channel activity causes in cerebellar granule cells the defects in neurite extension, cell migration and induction of cell death that are characteristic of weaver mice. One possibility is that the mutation causes an inability to regulate intracellular calcium levels properly. We tested this hypothesis by measuring intracellular calcium levels in granule cells and Purkinje cells in slices from the cerebellum of weaver mice. We report here that weaver mice have increases in resting calcium levels in their granule cells, which may account for the multiple effects of the weaver mutation upon these cells.


Assuntos
Cálcio/metabolismo , Cerebelo/metabolismo , Camundongos Mutantes Neurológicos/metabolismo , Neurônios/metabolismo , Canais de Potássio Corretores do Fluxo de Internalização , Canais de Potássio/genética , Animais , Química Encefálica/genética , Cerebelo/química , Cerebelo/citologia , Corantes Fluorescentes , Fura-2 , Canais de Potássio Corretores do Fluxo de Internalização Acoplados a Proteínas G , Camundongos , Mutação/fisiologia , Degeneração Neural/metabolismo , Neurônios/química , Fenótipo , Canais de Potássio/metabolismo
14.
J Am Mosq Control Assoc ; 13(3): 270-4, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9383770

RESUMO

Aedes albopictus was collected from water-holding rock holes along 3 streams in Georgia and 1 in South Carolina. To compare the occurrence of Ae. albopictus and Aedes atropalpus, rock holes were sampled for immature Aedes at 2 sites where there were numerous rock holes harboring mosquitoes. At 1 of these sites, tree holes and various types of artificial containers were also sampled for immature Aedes. At both sites, immature Ae. albopictus occurred in rock holes much less frequently than the rock-pool specialist, Aedes atropalpus. Moreover, the distribution of Ae. albopictus was limited to rock holes in less flood prone locations, whereas Ae. atropalpus was often a common mosquito even in rock holes that were among the most susceptible to flooding by rising stream levels. By contrast. Ae. albopictus was frequently found in the samples from tree holes and artificial containers. Thus, it appears that riverine rock holes that are flooded frequently may be, at best, marginal habitats for Ae. albopictus.


Assuntos
Aedes , Animais , Sudeste dos Estados Unidos
15.
J Am Mosq Control Assoc ; 11(2 Pt 1): 237, 1995 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-7595452

RESUMO

A statewide survey was conducted for Aedes albopictus in Georgia during the summers of 1991-94. All 159 counties in Georgia were determined to be infested. Aedes albopictus was widely distributed throughout all ecological regions in the survey area.


Assuntos
Aedes , Animais , Demografia , Georgia , Estados Unidos
16.
J Neurophysiol ; 73(5): 1793-8, 1995 May.
Artigo em Inglês | MEDLINE | ID: mdl-7623080

RESUMO

1. Using patch-clamp methods, we show that brief prepulses to very positive voltages increase (facilitate) the amplitude of current through Ca2+ channels during a subsequent test pulse in some, but not all, dorsal root ganglion (DRG) sensory neurons. The amplitude of this facilitated current generally increases when the Ca2+ channels are inhibited by activation of the mu-opioid receptor. 2. The facilitated current is blocked by omega-conotoxin GVIA, activates in the range of high-threshold Ca2+ channels, and inactivates at relatively negative holding voltages. Thus facilitated current passes through N-type Ca2+ channels, the same channels that are inhibited by opioids and control neurotransmitter release in sensory neurons. 3. Although maximal facilitation occurs only at unphysiologically high membrane potentials (above +100 mV), some facilitation is seen after prepulses to voltages reached during action potentials. After return to the holding potential, facilitation persists for hundreds of milliseconds, considerably longer than in other neurons. Brief trains of pulses designed to mimic action potentials caused small facilitation (19% of maximal) in a fraction (8 of 24) of opioid-inhibited neurons. 4. We conclude that 1) prepulses to extremely positive voltages can cause partial recovery of Ca2+ channels inhibited by opioids; and 2) small, but detectable, facilitation is also seen after physiological stimulation in some DRG neurons. Facilitation, largely considered a biophysical epiphenomenon because of the extreme voltages used to induce it, appears to be physiologically relevant during opioid inhibition of Ca2+ channels in DRG neurons.


Assuntos
Analgésicos/farmacologia , Gânglios Espinais/efeitos dos fármacos , Potenciais da Membrana/efeitos dos fármacos , Entorpecentes/farmacologia , Animais , Canais de Cálcio/efeitos dos fármacos , Células Cultivadas , Ala(2)-MePhe(4)-Gly(5)-Encefalina , Encefalinas/farmacologia , Peptídeos/farmacologia , Ratos , Ratos Endogâmicos , ômega-Conotoxina GVIA
17.
J Neurosci ; 15(5 Pt 2): 4124-32, 1995 May.
Artigo em Inglês | MEDLINE | ID: mdl-7538571

RESUMO

We used patch-clamp methods to describe signal transduction between the mu opioid receptor, the binding site for morphine, and high-threshold Ca2+ channels in dorsal root ganglion (DRG) sensory neurons from adult rats. Opioid signaling persists in excised membrane patches, and an activated opioid receptor can only inhibit nearby Ca2+ channels; thus, no readily diffusible second-messenger molecule mediates between the mu receptor and Ca2+ channels. Inhibition of Ca2+ channels begins several hundred msec after application of opioid and it is maximal by 5 sec; this is faster than typical phosphorylation cascades. Blockade of the known serine-threonine kinases and phosphatases does not affect this opioid signaling and, as shown previously by Seward et al. (1991) and Moises et al. (1994a), pertussis toxin eliminates virtually all of the effect. Inhibited channels can open, but their half-activation voltage is unphysiologically positive. The link between the mu receptor and Ca2+ channels is clearly unlike the protein kinase C-dependent paths that couple mu receptors to NMDA channels in dorsal horn neurons (Chen and Huang, 1991) and alpha-adrenergic receptors to Ca2+ channels in DRG neurons (Diversé-Pierluissi and Dunlap, 1993). The rapid kinetics and tight localization of the signaling path are properties expected if receptor and channel are linked directly by a G-protein, but these properties do not constitute proof of such a pathway.


Assuntos
Canais de Cálcio/fisiologia , Encefalinas/farmacologia , Gânglios Espinais/fisiologia , Neurônios Aferentes/fisiologia , Receptores Opioides mu/fisiologia , Transdução de Sinais , 1-Metil-3-Isobutilxantina/farmacologia , Alcaloides/farmacologia , Animais , Bucladesina/farmacologia , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio/efeitos dos fármacos , Células Cultivadas , Ala(2)-MePhe(4)-Gly(5)-Encefalina , Éteres Cíclicos/farmacologia , Cinética , Microcistinas , Neurônios Aferentes/efeitos dos fármacos , Ácido Okadáico , Técnicas de Patch-Clamp , Peptídeos Cíclicos/farmacologia , Toxina Pertussis , Fosfoproteínas Fosfatases/antagonistas & inibidores , Fosforilação , Inibidores de Proteínas Quinases , Ratos , Receptores Opioides mu/antagonistas & inibidores , Sistemas do Segundo Mensageiro/fisiologia , Transdução de Sinais/efeitos dos fármacos , Estaurosporina , Fatores de Tempo , Fatores de Virulência de Bordetella/farmacologia
18.
J Neurophysiol ; 72(3): 1192-8, 1994 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-7528792

RESUMO

1. We used microfluorimetric measurement of [Ca2+]i to identify substance P-sensitive cells acutely isolated from the dorsal horn of neonatal rats. We then used morphological, physiological, and immunocytochemical criteria to delineate two distinct populations of substance P-sensitive dorsal horn cells. 2. One population of cells with small-diameter cell bodies and many fine processes responds to substance P by releasing Ca2+ from internal stores. Many of these cells express the O4 surface antigen, and are thus likely to be glial cells, probably from the oligodendrocyte lineage. None of the cells with glial attributes respond to N-methyl-D-aspartate (NMDA), providing further evidence that they are nonneuronal. 3. In a second population of dorsal horn cells, substance P elevates [Ca2+]i by promoting Ca2+ entry. This class of cells is morphologically distinct from substance P-sensitive glial cells in that it exhibits large-diameter cell bodies, has smooth tapering processes, and is sensitive to NMDA. This second class of cells is therefore likely to consist of neurons. 4. Consistent with the identification of different mechanisms of Ca2+ elevation in the two cell types, the kinetics of the substance P-evoked release of Ca2+ in glial cells is very different than the kinetics of the Ca(2+)-entry response evoked in neurons. The glial cell response had a rapid average rate of rise (mean = 260 +/- 105 nM/s) and relatively brief duration (mean = 7.6 +/- 2.2 s) whereas the neuronal response had a much slower rate of rise (mean = 10 +/- 9 nM/s) with a much longer duration.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Canais de Cálcio/fisiologia , Cálcio/metabolismo , Gânglios Espinais/fisiologia , Neuroglia/fisiologia , Neurônios/fisiologia , Medula Espinal/fisiologia , Substância P/fisiologia , Transmissão Sináptica/fisiologia , Animais , Animais Recém-Nascidos , Técnicas de Cultura , Líquido Intracelular/fisiologia , Ratos , Ratos Sprague-Dawley , Receptores de N-Metil-D-Aspartato/fisiologia
19.
Am J Obstet Gynecol ; 170(3): 829-32, 1994 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8141211

RESUMO

OBJECTIVE: Our purpose was to evaluate the efficacy of amoxicillin as an alternative therapy to erythromycin for the treatment of cervical chlamydial infections during pregnancy. STUDY DESIGN: A randomized, prospective trial of two treatment regimens for Chlamydia trachomatis was performed in a cohort of pregnant women enrolled for care in an inner-city, university-based prenatal clinic, with an alternate-therapy crossover arm for primary treatment failures. Pregnant women diagnosed with chlamydial infection by McCoy cell culture of cervical swabs were assigned to receive either 500 mg of amoxicillin three times daily or 500 mg of erythromycin four times daily for 7 days. Patients' partners were treated with doxycycline. Compliance information was obtained by a standardized questionnaire at a posttherapy follow-up visit. Patients with positive follow-up cultures were crossed over into the alternate treatment arm and recultured at a later visit. RESULTS: During the study period 74 women consented to participate in this trial; 36 were treated with amoxicillin and 38 with erythromycin. Initial cure rates of 82.3% (28/34) for the amoxicillin group and 84.6% (27/32) for erythromycin were obtained before crossover (p = 0.91); four patients in each group were lost to follow-up. Overall cure rates after crossover were 84.6% (33/39) for amoxicillin and 84.2% (32/38) for erythromycin (p = 0.83). In the amoxicillin group 12.8% of patients reported side effects compared with 31.6% treated with erythromycin (p = 0.09), although seven erythromycin-treated patients compared with none of those in the amoxicillin arm stopped therapy because of side effects (p = 0.02). CONCLUSION: Amoxicillin offers a reasonable alternative to erythromycin for the treatment of Chlamydia trachomatis in pregnancy, on the basis of both cure rates and patient compliance.


Assuntos
Amoxicilina/uso terapêutico , Infecções por Chlamydia/tratamento farmacológico , Chlamydia trachomatis , Eritromicina/uso terapêutico , Complicações Infecciosas na Gravidez/tratamento farmacológico , Amoxicilina/efeitos adversos , Eritromicina/efeitos adversos , Feminino , Humanos , Gravidez , Estudos Prospectivos , Resultado do Tratamento
20.
J Am Mosq Control Assoc ; 9(3): 367-9, 1993 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8245952

RESUMO

A survey was conducted for Aedes albopictus in southern Texas during the summer of 1992. Thirty-five new country records were added to the distribution of this imported mosquito in Texas. Aedes albopictus was widely distributed throughout the ecological regions in the survey area, but its abundance decreased in counties adjacent to the Rio Grande River. However, these counties had high densities of Aedes aegypti.


Assuntos
Aedes , Animais , Ecologia , Densidade Demográfica , Texas
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