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1.
Am J Med ; 130(10): 1199-1204, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28551043

RESUMO

PURPOSE: Within 30 days of hospital discharge to a skilled nursing facility, older adults are at high risk for death, re-hospitalization, and high-cost health care. The purpose of this study was to examine whether a novel videoconference program called Extension for Community Health Outcomes-Care Transitions (ECHO-CT) that connects an interdisciplinary hospital-based team with clinicians at skilled nursing facilities reduces patient mortality, hospital readmission, skilled nursing facility length of stay, and 30-day health care costs. METHODS: We undertook a prospective cohort study comparing cost and health care utilization outcomes between ECHO-CT facilities and matched comparisons from January 2014-December 2014. RESULTS: Thirty-day readmission rates were significantly lower in the intervention group (odds ratio 0.57; 95% CI, 0.34-0.96; P-value .04), as were the 30-day total health care cost ($2602.19 lower; 95% CI, -$4133.90 to -$1070.48; P-value <.001) and the average length of stay at the skilled nursing facility (-5.52 days; 95% CI, -9.61 to -1.43; P = .001). The 30-day mortality rate was not significantly lower in the intervention group (odds ratio 0.38; 95% CI, 0.11-1.24; P = .11). CONCLUSION: Patients discharged to skilled nursing facilities participating in the ECHO-CT program had shorter lengths of stay, lower 30-day rehospitalization rates, and lower 30-day health care costs compared with those in matched skilled nursing facilities delivering usual care. ECHO-CT may improve patient transitions to postacute care at lower overall cost.


Assuntos
Continuidade da Assistência ao Paciente , Melhoria de Qualidade , Comunicação por Videoconferência , Idoso , Idoso de 80 Anos ou mais , Continuidade da Assistência ao Paciente/normas , Feminino , Custos de Cuidados de Saúde , Humanos , Tempo de Internação , Masculino , Alta do Paciente , Readmissão do Paciente/estatística & dados numéricos , Estudos Prospectivos , Instituições de Cuidados Especializados de Enfermagem
2.
J Am Geriatr Soc ; 65(3): 598-602, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28032896

RESUMO

OBJECTIVES: To examine whether a novel videoconference that connects an interdisciplinary hospital-based team with clinicians at postacute care sites improves interprofessional communication and reduces medication errors. DESIGN: Prospective cohort. SETTING: One tertiary care medical center and eight postacute care sites. PARTICIPANTS: Hospital-based providers (hospitalists, geriatricians, pharmacists, social workers, medical trainees, and subspecialists) and postacute care clinicians. INTERVENTION: All patients discharged to eight postacute care sites were discussed in a weekly videoconference. MEASUREMENT: Preliminary data including demographic characteristics of the patients discussed, postacute care provider satisfaction survey results, and data on medication errors are reported. RESULTS: Over 2 years, 907 patients were discussed; 84.6% were discussed with staff at subacute skilled nursing facilities and the remainder with clinicians at one long-term acute care facility. They had an average hospital length of stay of 6.8 days. Postacute care providers felt that the videoconference enhanced communication and provided much-needed access to information and hospital staff. Of the 106 pharmacy discrepancies identified, 16% involved an omission of a medication. CONCLUSION: As increasing numbers of older adults are discharged to postacute care facilities, they face high-risk care transitions. Extension for Community Healthcare Outcomes-Care Transitions (ECHO-CT) facilitates interdisciplinary communication between hospital and postacute care providers, who normally have minimal interaction. Preliminary data suggests that ECHO-CT may improve the transitions of care processes between these sites.


Assuntos
Continuidade da Assistência ao Paciente/organização & administração , Equipe de Assistência ao Paciente , Cuidados Semi-Intensivos/organização & administração , Comunicação por Videoconferência , Idoso , Estudos de Coortes , Feminino , Humanos , Comunicação Interdisciplinar , Assistência de Longa Duração , Masculino , Erros de Medicação/prevenção & controle , Reconciliação de Medicamentos , Alta do Paciente , Avaliação de Programas e Projetos de Saúde , Instituições de Cuidados Especializados de Enfermagem , Estados Unidos
3.
Curr Vasc Pharmacol ; 11(5): 712-29, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24063383

RESUMO

The challenge of pregnancy to the mother requires that her own metabolic and endocrine needs be met while also taking on the literally growing demands of the unborn child. While all of the mother's organs require continued support, the uterus and now added placenta must also develop substantially. One critical area of adaptation is thus the ability to provide added blood flow over and above that already serving the preexisting maternal organs. Previous reviews have covered in detail how this is achieved from an endocrine or indeed vascular physiology standpoint and we will not repeat that here. Suffice it to say in addition to new vessel growth, there is also the need to achieve reduced vascular resistance through maintenance of endothelial vasodilation, particularly through NO and PGI2 production in response to multiple agonists and their associated cell signaling systems. In this review, we continue our focus on pregnancy adaptive changes at the level of cell signaling, with a particular emphasis now on the developing story of the critical role of gap junctions. Remapping of cell signaling itself beyond changes in individual hormones and respective receptors brings about global changes in cell function, and recent studies have revealed that such post-receptor changes in cell signaling are equally if not more important in the process of pregnancy adaptation of endothelial function than the upregulated expression of vasodilator synthetic pathways themselves. The principle significance, however, of reviewing this aspect of pregnancy adaptation of endothelial cell function is that these same gap junction proteins that mediate pregnancy-adapted changes in vasodilatory signaling function may also be the focal point of failure in diseased pregnancy, and clues as to how and why are given by comparing studies of Cx43 functional suppression at wound sites with studies of preeclamptic pregnancy. If preeclamptic pregnancy is indeed a pregnancy misconstrued by the body in endocrine terms to be a wound, then the kinases so activated that correspondingly suppress Cx43 function in the vascular endothelium may also be valid pharmacologic targets for novel therapies in the near future.


Assuntos
Adaptação Fisiológica/fisiologia , Endotélio Vascular/fisiopatologia , Junções Comunicantes/fisiologia , Pré-Eclâmpsia/fisiopatologia , Animais , Feminino , Humanos , Gravidez
4.
Am J Transplant ; 12(11): 2949-57, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22759344

RESUMO

With the increase in patients having impaired renal function at liver transplant due to MELD, accurate predictors of posttransplant native renal recovery are needed to select candidates for simultaneous liver-kidney transplantation (SLK). Current UNOS guidelines rely on specific clinical criteria for SLK allocation. To examine these guidelines and other variables predicting nonrecovery, we analyzed 155 SLK recipients, focusing on a subset (n = 78) that had post-SLK native GFR (nGFR) determined by radionuclide renal scans. The 77 patients not having renal scans received a higher number of extended criteria donor organs and had worse posttransplant survival. Of the 78 renal scan patients, 31 met and 47 did not meet pre-SLK UNOS criteria. The UNOS criteria were more predictive than our institutional criteria for all nGFR recovery thresholds (20-40 mL/min), although at the most conservative cut-off (nGFR ≤ 20) it had low sensitivity (55.3%), specificity (75%), PPV (67.6%) and NPV (63.8%) for predicting post-SLK nonrecovery. On multivariate analysis, the only predictor of native renal nonrecovery (nGFR ≤ 20) was abnormal pre-SLK renal imaging (OR 3.85, CI 1.22-12.5). Our data support the need to refine SLK selection utilizing more definitive biomarkers and predictors of native renal recovery than current clinical criteria.


Assuntos
Transplante de Rim/métodos , Rim/diagnóstico por imagem , Transplante de Fígado/métodos , Seleção de Pacientes , Adulto , Análise de Variância , Estudos de Coortes , Feminino , Seguimentos , Taxa de Filtração Glomerular , Rejeição de Enxerto , Sobrevivência de Enxerto , Humanos , Rim/patologia , Testes de Função Renal , Transplante de Rim/efeitos adversos , Transplante de Fígado/efeitos adversos , Doadores Vivos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Cuidados Pós-Operatórios/métodos , Cuidados Pré-Operatórios/métodos , Cintilografia , Recuperação de Função Fisiológica , Estudos Retrospectivos , Medição de Risco , Estatísticas não Paramétricas , Resultado do Tratamento
5.
Br J Anaesth ; 104(4): 472-81, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20179014

RESUMO

BACKGROUND: Propofol is an i.v. anaesthetic commonly used during general anaesthesia and intensive care. It is known that the second transmembrane segment of the beta subunit in the GABA(A) receptor is an important target for the effects of propofol; however, this has not been investigated in human receptors. The aim of this study was to investigate the effect of propofol on human beta2 and beta3 GABA(A) subunits with point mutations corresponding to the N265M mutation in the rat beta2 and beta3 subunits. METHODS: Asparagine-to-methionine replacement at amino acid position 289 and 290 (N289M and N290M) in the beta2 and beta3 GABA(A) receptor subunits, respectively, was accomplished by site-directed mutagenesis. Thereafter, subunits for three human wild-type (alpha1beta2gamma2, alpha2beta2gamma2, and alpha2beta3gamma2) and two mutant GABA(A) receptor channels [alpha1beta2(N289M)gamma2 and alpha2beta3(N290M)gamma2] were introduced into Xenopus oocytes and studied with two-electrode voltage clamp. RESULTS: The mutant receptors left-shifted the GABA concentration-response curve. In comparison with the wild-type receptors, both the positive modulatory and the agonistic effects of propofol were strongly reduced in potency and amplitude at both mutated GABA(A) channels. CONCLUSIONS: We demonstrate that N289M or N290M mutation in human GABA(A) beta2 and beta3 subunits increases sensitivity to GABA, which is in contrast to the corresponding rat N265M mutation. Furthermore, the N289M and N289M mutations reduce both the potentiation of GABA-induced currents and the direct effect of propofol on channels incorporating either of the mutated subunits, which confirms earlier findings concerning the corresponding mutation in rat receptors and knock-in mice.


Assuntos
Anestésicos Intravenosos/farmacologia , Propofol/farmacologia , Receptores de GABA-A/efeitos dos fármacos , Sequência de Aminoácidos , Animais , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Feminino , Humanos , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Oócitos/metabolismo , Técnicas de Patch-Clamp , Mutação Puntual , Ratos , Receptores de GABA-A/genética , Receptores de GABA-A/metabolismo , Alinhamento de Sequência , Xenopus laevis , Ácido gama-Aminobutírico/farmacologia
6.
Nat Neurosci ; 4(6): 587-96, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11369939

RESUMO

Tyrosine phosphorylation can upregulate NMDA receptor activity during pathological and physiological alterations of synaptic strength. Here we describe downregulation of recombinant NR1/2A receptors by tyrosine dephosphorylation that requires agonist binding, but is independent of ion flux. The tyrosine residues involved in this new form of NMDA receptor modulation likely form a 'ring' adjacent to the last transmembrane domain. The downregulation was due to a reduction in the number of functional channels, and was blocked by co-expressing a dominant-negative mu2-subunit of the clathrin-adaptor protein AP-2. Our results provide a mechanism by which synaptic NMDA receptors can be modulated in a use-dependent manner even when the postsynaptic membrane is not sufficiently depolarized to relieve channel block by magnesium ions.


Assuntos
Complexo 1 de Proteínas Adaptadoras , Complexo 2 de Proteínas Adaptadoras , Complexo 3 de Proteínas Adaptadoras , Subunidades mu do Complexo de Proteínas Adaptadoras , Fosfotirosina/metabolismo , Receptores de N-Metil-D-Aspartato/fisiologia , Sinapses/fisiologia , Proteínas Adaptadoras de Transporte Vesicular , Bicuculina/farmacologia , Antígenos CD4/genética , Antígenos CD4/fisiologia , Cálcio/fisiologia , Linhagem Celular , Membrana Celular/fisiologia , Clonagem Molecular , Maleato de Dizocilpina/farmacologia , Regulação para Baixo , Ácido Egtázico/análogos & derivados , Ácido Egtázico/farmacologia , Inibidores Enzimáticos/farmacologia , Humanos , Magnésio/farmacologia , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Técnicas de Patch-Clamp , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Subunidades Proteicas , Receptores de N-Metil-D-Aspartato/química , Receptores de N-Metil-D-Aspartato/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes/metabolismo , Tetrodotoxina/farmacologia , Transfecção , Regulação para Cima
8.
J Neurosci ; 19(4): 1165-78, 1999 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-9952395

RESUMO

Glutamate receptors are associated with various regulatory and cytoskeletal proteins. However, an understanding of the functional significance of these interactions is still rudimentary. Studies in hippocampal neurons suggest that such interactions may be involved in calcium-induced reduction in the open probability of NMDA receptors (inactivation). Thus we examined the role of the intracellular domains of the NR1 subunit and two of its binding partners, calmodulin and alpha-actinin, on this process using NR1/NR2A heteromers expressed in human embryonic kidney (HEK) 293 cells. The presence of the first 30 residues of the intracellular C terminus of NR1 (C0 domain) was required for inactivation. Mutations in the last five residues of C0 reduced inactivation and produced parallel shifts in binding of alpha-actinin and Ca2+/calmodulin to the respective C0-derived peptides. Although calmodulin reduced channel activity in excised patches, calmodulin inhibitors did not block inactivation in whole-cell recording, suggesting that inactivation in the intact cell is more complex than binding of calmodulin to C0. Overexpression of putative Ca2+-insensitive, but not Ca2+-sensitive, forms of alpha-actinin reduced inactivation, an effect that was overcome by inclusion of calmodulin in the whole-cell pipette. The C0 domain also directly affects channel gating because NR1 subunits with truncated C0 domains that lacked calmodulin or alpha-actinin binding sites had a low open probability. We propose that inactivation can occur after C0 dissociates from alpha-actinin by two distinct but converging calcium-dependent processes: competitive displacement of alpha-actinin by calmodulin and reduction in the affinity of alpha-actinin for C0 after binding of calcium to alpha-actinin.


Assuntos
Actinina/fisiologia , Cálcio/fisiologia , Calmodulina/fisiologia , Receptores de N-Metil-D-Aspartato/fisiologia , Actinina/biossíntese , Sequência de Aminoácidos , Animais , Ligação Competitiva/fisiologia , Galinhas , DNA Complementar/biossíntese , DNA Complementar/genética , Estimulação Elétrica , Eletrofisiologia , Humanos , Ativação do Canal Iônico/genética , Ativação do Canal Iônico/fisiologia , Potenciais da Membrana/fisiologia , Dados de Sequência Molecular , Técnicas de Patch-Clamp , Receptores de N-Metil-D-Aspartato/genética , Proteínas Recombinantes/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa
9.
Neuron ; 20(2): 317-27, 1998 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9491992

RESUMO

Recent molecular studies of glutamate channels have provided increasingly detailed models of the agonist-binding site and of the channel pore. However, little information is available on the domains involved in channel gating. We examined the molecular determinants for the NR2-subunit specificity of glycine-independent desensitization of NMDA channels using NR2C/NR2A chimeric subunits expressed in HEK 293 cells. We show that glycine-independent desensitization is controlled by N-terminal domains of the NR2 subunit that flank the putative agonist-binding domain: a four amino acid (aa) segment immediately preceding the first transmembrane domain (M1) and a region containing the leucine/isoleucine/valine-binding protein-like (LIVBP-like) domain. Our results provide evidence for a functional role of the region containing the LIVBP-like domain in glutamate receptor channels. We suggest that the pre-M1 segment, presumably situated near the entrance to the pore, serves as a dynamic link between ligand binding and channel gating.


Assuntos
Ativação do Canal Iônico/fisiologia , Receptores de N-Metil-D-Aspartato/química , Receptores de N-Metil-D-Aspartato/genética , Sequência de Aminoácidos , Células Cultivadas , Clonagem Molecular , Eletrofisiologia , Agonistas de Aminoácidos Excitatórios/metabolismo , Agonistas de Aminoácidos Excitatórios/farmacologia , Glicina/metabolismo , Glicina/farmacologia , Humanos , Ativação do Canal Iônico/efeitos dos fármacos , Rim/citologia , Ligantes , Dados de Sequência Molecular , Estrutura Terciária de Proteína , Receptores de N-Metil-D-Aspartato/metabolismo , Sensibilidade e Especificidade
10.
Eur J Neurosci ; 9(8): 1711-9, 1997 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9283825

RESUMO

The time pattern of glycinergic inhibitory postsynaptic currents (IPSCs) in sympathetic preganglionic neurons was studied in thin transverse spinal cord slices of neonatal (1-10 days postnatal) rats by means of the patchclamp technique. Three time patterns could be distinguished: (i) large events [mostly > 400 pA (30-36 degrees C)] occurring at regular intervals, (ii) small events occurring at irregular intervals, and (iii) small events occurring in transient (1.5-10 s), high-frequency (> 15 Hz) bursts of synaptic activity. The large regular events had uniform kinetics which was consistent with the idea of a proximal site of origin for all of these events. They were reversibly inhibited in amplitude and frequency by extracellular application of a high concentration of acetylcholine (200 microM) or the specific nicotinic acetylcholine receptor agonist dimethylphenylpiperazinium iodide (DMPP; 1 mM), but unaffected by glutamate (100 microM). IPSCs occurring in bursts had slower and less uniform kinetics, suggesting a more diverse site of origin. The frequency of events decreased during a burst. Similar bursts could be induced by extracellular application of glutamate receptor agonists. These results indicate that sympathetic pregnanglionic neurons in a thin, transverse spinal cord slice receive at least two different glycinergic inputs.


Assuntos
Fibras Autônomas Pré-Ganglionares/fisiologia , Glicina/fisiologia , Neurônios/fisiologia , Sistema Nervoso Simpático/fisiologia , Animais , Animais Recém-Nascidos , Fibras Autônomas Pré-Ganglionares/citologia , Agonistas de Aminoácidos Excitatórios/farmacologia , Técnicas In Vitro , Agonistas Nicotínicos/farmacologia , Técnicas de Patch-Clamp , Ratos , Medula Espinal/fisiologia , Sistema Nervoso Simpático/citologia , Transmissão Sináptica/efeitos dos fármacos , Transmissão Sináptica/fisiologia
11.
Soc Gen Physiol Ser ; 52: 163-75, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9210228

RESUMO

The data presented here are clearly just the beginning of any comprehensive understanding of the set of regulatory and cytoskeletal proteins that interact with membrane receptors in the postsynaptic density. They do, however, indicate that both glutamate channels at central excitatory synapses are involved in complex protein-protein interactions. For example, while NR2A is important for Ca-dependent inactivation of NMDA receptors, studies in several systems suggest that the other major NR2 subunit in hippocampal neurons, NR2B, predominates at critical times during synapse formation. In addition, the COOH terminus of NR2B binds to several novel cytoskeletal proteins. These results provide circumstantial evidence that NR2B may play specific roles in function and localization of receptors at excitatory synapses. The possible role of NR2B in early synaptic function gains additional support from functional data suggesting that NMDA receptors have specific roles during development (Komuro and Rakic, 1993; Rabacchi et al., 1992; Yen et al., 1993). The essential role of NR1 and NR2B in development is graphically demonstrated by the neonatal death of transgenic mice lacking either of these two subunits (Forrest et al., 1994; Kutsuwada et al., 1996) whereas NR2A and NR2C-deficient mice are less severely affected (Sakimura et al., 1995; Ebralidze et al., 1996).


Assuntos
Citoesqueleto/metabolismo , Receptores de Glutamato/metabolismo , Sinapses/química , Animais , Neurônios/química , Neurônios/metabolismo , Neurônios/ultraestrutura , Sinapses/metabolismo
12.
Mol Pharmacol ; 50(6): 1680-8, 1996 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8967993

RESUMO

Intracellular Ca2+ can reversibly reduce the activity of native N-methyl-D-aspartate (NMDA) receptors in hippocampal neurons, a phenomenon termed Ca2+-dependent inactivation. We examined inactivation in heteromeric NMDA receptors expressed in human embryonic kidney (HEK) 293 cells using whole-cell recording. NR1-1a/2A heteromers showed reversible inactivation that was very similar to native NMDA receptors in cultured hippocampal neurons. Inactivation was dependent on the extracellular Ca2+ concentration and the degree of intracellular Ca2+ buffering. In 2 mM extracellular Ca2+, inactivation resulted in a 46.1 +/- 12.6% reduction in the whole-cell current during a 5-sec agonist application. Inactivation of NR1-1a/2A heteromers was unaffected by calcineurin inhibitors, staurosporine, or phalloidin. NR1-1a/2D heteromers also showed a similar degree of inactivation. In contrast, NR1-1a/2B and NR1-1a/2C heteromers showed no significant inactivation. At saturating concentrations of NMDA (1 mM), NR1-1a/2A heteromers also showed Ca- and glycine-independent desensitization, as seen in native hippocampal neurons. Ca(2+)- and glycine-independent desensitization was less pronounced in NR1-1a/2B heteromers and absent in NR1-1a/2C heteromers. Activation of NR1-1a/2C heteromers triggered intracellular Ca2+ transients similar to NR1-1a/2A heteromers as verified by combined Ca2+ imaging and whole-cell recording. Thus differences in Ca2+ permeability were not responsible for the lack of inactivation in NR1-1a/2C heteromers. Our results show that inactivation of recombinant NMDA receptors requires either the NR2A or NR2D subunit, whereas both inactivation and desensitization were absent in NR2C-containing receptors. The gating of inactivating NMDA receptors is more likely to be influenced by ongoing NMDA receptor activity and Ca2+ transients, perhaps consistent with the prominent expression of NR2A in hippocampus and cerebral cortex.


Assuntos
Cálcio/metabolismo , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Biopolímeros , Linhagem Celular , Humanos , Fosfoproteínas Fosfatases/metabolismo , Proteínas Recombinantes/antagonistas & inibidores
13.
J Neurophysiol ; 73(4): 1503-12, 1995 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-7543945

RESUMO

1. We obtained whole cell patch-clamp recordings from visually identified sympathetic preganglionic neurons (SPNs) in thin (200-300 microns) transverse spinal cord slices of neonatal rats (1-14 days postnatal). Exogenous application of glutamate (100 microM), N-methyl-D-aspartate (NMDA; 100 microM), kainate (100 microM), quisqualate (1 microM), and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA; 50 microM) induced inward currents at a holding potential of -30 mV. 2. Excitatory postsynaptic currents (EPSCs) were evoked by electrical stimulation either in the dorsal horn or the lateral funiculus. They reversed at 1.2 +/- 4.6 (SD) mV and could in most cases (49 of 51) be separated into two components. 3. In the presence of DL-2-amino-5-phosphonovalerate (10-40 microM) the current-voltage (I-V) relationship of the remaining EPSC was linear. When stimulated in the lateral funiculus, its rise time (10-90%) and the time constant of the monoexponential decay were 1.6 +/- 1.0 and 5.5 +/- 2.7 ms, respectively. By contrast, when stimulated in the dorsal horn, this component had a rise time (10-90%) of 3.0 +/- 0.8 ms and a decay time constant of 13.7 +/- 7.6 ms. 4. We studied the NMDA receptor-mediated component of the EPSCs after superfusion of 6-cyano-7-nitroquinoxaline-2,3-dione (5 microM). The I-V relationship of this component had a region of negative slope conductance between -30 and -80 mV, which was abolished in Mg(2+)-free saline. The rise time (10-90%) ranged from 3.3 to 9.5 ms and the decay was biexponential. Both decay time constants increased with depolarization. Mg(2+)-free saline reduced this voltage sensitivity. 5. At a membrane potential of -80 mV and in 1 mM extracellular Mg2+, the NMDA receptor-mediated component represented 74.8 +/- 11.2% of the total charge carried by the EPSCs evoked by stimulation in the dorsal horn. In contrast, when stimulated from the lateral funiculus, 28.9 +/- 18.9% of the total charge carried during the EPSC was mediated by the NMDA receptor-mediated component. The contribution of the NMDA receptor-mediated component increased in both cases with depolarization. In addition, in 2 of 18 SPNs the EPSC evoked in the dorsal horn was exclusively carried by NMDA receptors. 6. We conclude that L-glutamate or a related substance mediates the fast excitatory input onto SPNs. Viscerosomatic and supraspinal inputs form synapses with different topographical locations on the SPN.(ABSTRACT TRUNCATED AT 400 WORDS)


Assuntos
Fibras Autônomas Pré-Ganglionares/fisiologia , Canais Iônicos/fisiologia , Receptores de Glutamato/fisiologia , Sistema Nervoso Simpático/fisiologia , Sinapses/fisiologia , Animais , Animais Recém-Nascidos , Fibras Autônomas Pré-Ganglionares/efeitos dos fármacos , Estimulação Elétrica , Antagonistas de Aminoácidos Excitatórios/farmacologia , Técnicas In Vitro , Canais Iônicos/efeitos dos fármacos , Cinética , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Ratos , Ratos Wistar , Receptores de AMPA/efeitos dos fármacos , Receptores de Glutamato/efeitos dos fármacos , Receptores de N-Metil-D-Aspartato/efeitos dos fármacos , Medula Espinal/citologia , Medula Espinal/efeitos dos fármacos , Medula Espinal/metabolismo , Sistema Nervoso Simpático/citologia , Sinapses/efeitos dos fármacos , Membranas Sinápticas/efeitos dos fármacos , Membranas Sinápticas/metabolismo
14.
Neuroreport ; 5(18): 2437-40, 1994 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-7696575

RESUMO

The characteristics of glycinergic inhibitory postsynaptic currents (IPSCs) in sympathetic preganglionic neurons (SPNs) of neonatal rats were studied by whole-cell recordings in transverse spinal cord slices. In relation to postnatal age, the decay time constants of these currents decreased without a comparable effect on their rise time. This may result from alpha-subunit switching of the glycine receptor and/or increased glycine uptake during this period of postnatal life. The kinetics of glycinergic IPSCs were also temperature- and voltage-dependent. Whereas, compared with room temperature, rise and decay of the events were faster at more physiological temperature, only the decay increased upon depolarization. Visual identification of SPNs was confirmed by intracellular staining and comparison with retrogradely labeled SPNs.


Assuntos
Gânglios Simpáticos/fisiologia , Glicina/fisiologia , Inibição Neural/fisiologia , Neurônios/fisiologia , Sinapses/fisiologia , Animais , Animais Recém-Nascidos , Condutividade Elétrica , Eletrofisiologia , Gânglios Simpáticos/citologia , Técnicas In Vitro , Cinética , Neurônios/citologia , Ratos , Medula Espinal/fisiologia , Fatores de Tempo
15.
Nat Toxins ; 2(4): 152-65, 1994.
Artigo em Inglês | MEDLINE | ID: mdl-7952939

RESUMO

Cultured isolates of Pseudonitzschia australis Frenguelli, P. delicatissima (Cleve) Heiden, P. americana (Hasle) Fryxell, P. pungens (Grunow) Hasle, and P. pungens f. multiseries (Hasle) Hasle from Monterey Bay, California, were compared on the basis of their large-subunit ribosomal RNA gene (LsrDNA). Pseudonitzschia australis, P. pungens f. multiseries, and P. delicatissima were previously shown to produce the neurotoxin domoic acid; the remaining isolates are considered non-toxic. For each isolate approximately 800 base pairs of LsrDNA, encompassing both evolutionarily conserved and evolutionarily variable regions of the molecule, were amplified using the polymerase chain reaction (PCR) and sequenced. Phylogenetic trees generated by parsimony analysis of aligned sequences afford a preliminary view of the organisms genetic relationships. Species defined by morphological criteria are also distinguishable by LsrDNA sequence. Organisms known or suspected to produce domoic acid cluster at different termini on the phylogenetic tree. Two genetically distinct strains of P. australis and P. pungens were identified. Development of a restriction fragment length polymorphism (RFLP) assay of the LsrDNA is described. The RFLP assay discriminates each species, including distinguished strains of P. australis and P. pungens. The restriction test provides a rapid and convenient method for screening isolates' LsrDNA, facilitating further tests of the apparent positive correlation between Pseudonitzschia species' ribosomal gene signatures, morphology, and capacity to produce domoic acid.


Assuntos
DNA Ribossômico/genética , Diatomáceas/classificação , Fitoplâncton/classificação , Polimorfismo de Fragmento de Restrição , RNA Ribossômico/genética , Sequência de Bases , Diatomáceas/genética , Ácido Caínico/análogos & derivados , Ácido Caínico/intoxicação , Microscopia Eletrônica de Varredura , Dados de Sequência Molecular , Fármacos Neuromusculares Despolarizantes/intoxicação , Fitoplâncton/genética , Reação em Cadeia da Polimerase , Especificidade da Espécie
16.
J Physiol ; 471: 729-48, 1993 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-8120831

RESUMO

1. By using the whole-cell recording configuration of the patch-clamp technique in a spinal cord slice preparation, we have made recordings from visually identified neurones in the lateral horn of the thoracic and lumbar spinal cord of neonatal rats (newborn to 14 days postnatal). 2. Some of the recorded neurones were labelled with the fluorescent dye Lucifer Yellow (n = 27). Their morphology was typical for sympathetic preganglionic neurones (SPNs). Based on the size of the cell soma and the electrophysiological properties, unlabelled neurones were also regarded as SPNs. 3. Spontaneous synaptic activity of different patterns could be observed in 73% of the recorded neurones (n = 106). It reversed at the chloride equilibrium potential (ECl) and could be reversibly blocked by strychnine (1-10 microM), but not by bicuculline (10 microM) or SR95531 (5-10 microM). 4. Synaptic activity could be elicited by focal electrical stimulation in the vicinity of the recorded neurone. These evoked synaptic events exhibited features similar to the spontaneous synaptic activity. 5. Application of glycine (100 microM-1 mM) by a fast microperfusion system induced a chloride current in twenty-seven out of thirty cells tested. The currents were reversibly blocked by strychnine (1-10 microM), but were only weakly sensitive to bicuculline (10 microM). Stability of current responses to glycine was increased by inclusion of ATP (4 mM) in the intracellular medium. 6. Application of gamma-aminobutyric acid (GABA; 100 microM-1 mM) by the fast microperfusion system induced a chloride current in all twenty neurones tested. These currents were reversibly blocked by bicuculline (10 microM). Strychnine (1-10 microM) blocked this current only weakly. Run-down of GABA-induced currents was prevented to a great extent by inclusion of ATP (4 mM) in the pipette. 7. These results suggest that the inhibitory synaptic activity recorded from SPNs in thin, transverse slices of neonatal rat spinal cord is mediated by glycine receptor-gated Cl- channels. GABAA receptor-gated Cl- channels might be activated by inputs from other spinal segments and/or descending pathways from higher brain regions.


Assuntos
Cloretos/metabolismo , Gânglios Simpáticos/metabolismo , Animais , Animais Recém-Nascidos , Canais de Cloreto/efeitos dos fármacos , Canais de Cloreto/metabolismo , Estimulação Elétrica , Potenciais Evocados/efeitos dos fármacos , Potenciais Evocados/fisiologia , Corantes Fluorescentes , Gânglios Simpáticos/efeitos dos fármacos , Glicina/metabolismo , Glicina/farmacologia , Técnicas In Vitro , Isoquinolinas , Potenciais da Membrana/fisiologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Ratos , Ratos Wistar , Estricnina/farmacologia , Sinapses/efeitos dos fármacos , Sinapses/metabolismo , Ácido gama-Aminobutírico/farmacologia
17.
Bioelectromagnetics ; 13(6): 469-96, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1482413

RESUMO

Our goal was to investigate effects of long-term exposure to pulsed microwave radiation. The major emphasis was to expose a large sample of experimental animals throughout their lifetimes and to monitor them for effects on general health and longevity. An exposure facility was developed that enabled 200 rats to be maintained under specific-pathogen-free (SPF) conditions while housed individually in circularly-polarized waveguides. The exposure facility consisted of two rooms, each containing 50 active waveguides and 50 waveguides for sham (control) exposures. The experimental rats were exposed to 2,450-MHz pulsed microwaves at 800 pps with a 10-microseconds pulse width. The pulsed microwaves were square-wave modulated at 8-Hz. Whole body calorimetry, thermographic analysis, and power-meter analysis indicated that microwaves delivered at 0.144 W to each exposure waveguide resulted in an average specific absorption rate (SAR) that ranged from 0.4 W/kg for a 200-g rat to 0.15 W/kg for an 800-g rat. Two hundred male, Sprague-Dawley rats were assigned in equal numbers to radiation-exposure and sham-exposure conditions. Exposure began at 8 weeks of age and continued daily, 21.5 h/day, for 25 months. Animals were bled at regular intervals and blood samples were analyzed for serum chemistries, hematological values, protein electrophoretic patterns, thyroxine, and plasma corticosterone levels. In addition to daily measures of body mass, food and water consumption by all animals, O2 consumption and CO2 production were periodically measured in a sub-sample (N = 18) of each group. Activity was assessed in an open-field apparatus at regular intervals throughout the study. After 13 months, 10 rats from each group were euthanatized to test for immunological competence and to permit whole-body analysis, as well as gross and histopathological examinations. At the end of 25 months, the survivors (11 sham-exposed and 12 radiation-exposed rats) were euthanatized for similar analyses. The other 157 animals were examined histopathologically when they died spontaneously or were terminated in extremis.


Assuntos
Micro-Ondas , Animais , Comportamento Animal/efeitos da radiação , Análise Química do Sangue , Peso Corporal/efeitos da radiação , Corticosterona/sangue , Imunidade/efeitos da radiação , Longevidade/efeitos da radiação , Masculino , Neoplasias Induzidas por Radiação/etiologia , Doses de Radiação , Ratos , Ratos Sprague-Dawley , Fatores de Tempo
19.
Virus Res ; 7(2): 117-29, 1987 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-3035815

RESUMO

Varicella-zoster virus (VZV) DNA was detected in mononuclear cells (MNC) of 7 humans with acute zoster 1-23 days after the onset of skin lesions. To further study the interaction of VZV with human MNC, cells obtained from seropositive normal donors were infected with VZV and analyzed for the presence of viral DNA and proteins. VZV-DNA was detected in T, B, and OKM 1 (monocyte-macrophage) positive cells, and virus-specific proteins were demonstrated by indirect immunofluorescence and immunoprecipitation. Hybridization studies revealed that VZV-DNA did not replicate in human MNC.


Assuntos
DNA Viral/análise , Herpes Zoster/microbiologia , Herpesvirus Humano 3/fisiologia , Monócitos/microbiologia , Proteínas Virais/análise , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Antivirais/análise , Replicação do DNA , DNA Viral/biossíntese , Feminino , Herpesvirus Humano 3/genética , Herpesvirus Humano 3/imunologia , Humanos , Técnicas Imunológicas , Masculino , Pessoa de Meia-Idade , Hibridização de Ácido Nucleico , Proteínas Virais/biossíntese , Viremia , Replicação Viral
20.
J Bacteriol ; 169(2): 920-3, 1987 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-3100507

RESUMO

The morphology and ultrastructure of Anabaena variabilis grown in medium with and without 40 mM fructose were compared. Vegetative cells and young heterocysts in fructose-supplemented medium were significantly larger, were filled with glycogen granules, and had fewer thylakoids. Developing heterocysts contained large numbers of glycogen granules well into mature stages, and envelope formation was precocious. As heterocysts enlarged in fructose medium, their shape became more broadly oblong compared with the more rectangular heterocysts in fructose-free medium.


Assuntos
Cianobactérias/crescimento & desenvolvimento , Frutose/metabolismo , Meios de Cultura , Cianobactérias/citologia , Cianobactérias/ultraestrutura , Microscopia Eletrônica
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