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1.
AJNR Am J Neuroradiol ; 44(6): 700-706, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37142433

RESUMO

BACKGROUND AND PURPOSE: Children with spastic cerebral palsy have motor deficits associated with periventricular leukomalacia indicating WM damage to the corticospinal tracts. We investigated whether practice of skilled lower extremity selective motor control movements would elicit neuroplasticity. MATERIALS AND METHODS: Twelve children with spastic bilateral cerebral palsy and periventricular leukomalacia born preterm (mean age, 11.5 years; age range, 7.3-16.6 years) participated in a lower extremity selective motor control intervention, Camp Leg Power. Activities promoted isolated joint movement including isokinetic knee exercises, ankle-controlled gaming, gait training, and sensorimotor activities (3 hours/day, 15 sessions, 1 month). DWI scans were collected pre- and postintervention. Tract-Based Spatial Statistics was used to analyze changes in fractional anisotropy, radial diffusivity, axial diffusivity, and mean diffusivity. RESULTS: Significantly reduced radial diffusivity (P < . 05) was found within corticospinal tract ROIs, including 28.4% of the left and 3.6% of the right posterior limb of the internal capsule and 14.1% of the left superior corona radiata. Reduced mean diffusivity was found within the same ROIs (13.3%, 11.6%, and 6.6%, respectively). Additionally, decreased radial diffusivity was observed in the left primary motor cortex. Additional WM tracts had decreased radial diffusivity and mean diffusivity, including the anterior limb of the internal capsule, external capsule, anterior corona radiata, and corpus callosum body and genu. CONCLUSIONS: Myelination of the corticospinal tracts improved following Camp Leg Power. Neighboring WM changes suggest recruitment of additional tracts involved in regulating neuroplasticity of the motor regions. Intensive practice of skilled lower extremity selective motor control movements promotes neuroplasticity in children with spastic bilateral cerebral palsy.


Assuntos
Paralisia Cerebral , Leucomalácia Periventricular , Substância Branca , Recém-Nascido , Humanos , Criança , Adolescente , Paralisia Cerebral/complicações , Paralisia Cerebral/diagnóstico por imagem , Imagem de Tensor de Difusão , Perna (Membro) , Espasticidade Muscular , Extremidade Inferior , Anisotropia
2.
AJNR Am J Neuroradiol ; 42(11): 2054-2061, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34593378

RESUMO

BACKGROUND AND PURPOSE: Selective voluntary motor control is an important factor influencing gross motor function, interjoint coordination, and the outcome of hamstring-lengthening surgery in spastic cerebral palsy. Using DTI, we investigated whether selective voluntary motor control would show strong correlations with WM motor tract microstructure and whether selective voluntary motor control is more sensitive to global WM impairment than gross motor function. MATERIALS AND METHODS: Children with spastic bilateral cerebral palsy born preterm and typically developing children were recruited. The Selective Control Assessment of the Lower Extremity (SCALE) and Gross Motor Function Measure (GMFM) were assessed in participants with cerebral palsy. Participants underwent brain MR imaging to collect DWI data. Tract-Based Spatial Statistics was used to analyze the WM for between-group differences and correlations with SCALE and GMFM. ROI analyses compared motor regions. RESULTS: Twelve children with cerebral palsy (mean age, 11.5 years) and 12 typically developing children (mean age, 10.3 years) participated. Altered DTI outcomes were found throughout the whole brain for the cerebral palsy group. SCALE, developed to evaluate selective voluntary motor control in cerebral palsy, showed significant positive correlations with fractional anisotropy in more WM voxels throughout the whole brain and for motor regions, including the corticospinal tract and corpus callosum, compared with GMFM. A significant negative correlation between radial diffusivity and SCALE, but not GMFM, was found within the corpus callosum. CONCLUSIONS: SCALE was a more sensitive clinical correlate of motor and whole-brain WM tract impairment in children with spastic bilateral cerebral palsy, suggesting greater anisotropy and myelination in these regions for those with higher selective voluntary motor control.


Assuntos
Paralisia Cerebral , Substância Branca , Encéfalo/diagnóstico por imagem , Paralisia Cerebral/diagnóstico por imagem , Criança , Imagem de Tensor de Difusão , Humanos , Recém-Nascido , Espasticidade Muscular
3.
Proc Math Phys Eng Sci ; 473(2199): 20160812, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28413347

RESUMO

We present a computational model for the interaction of surface- and volume-bound scalar transport and reaction processes with a deformable porous medium. The application in mind is pericellular proteolysis, i.e. the dissolution of the solid phase of the extracellular matrix (ECM) as a response to the activation of certain chemical species at the cell membrane and in the vicinity of the cell. A poroelastic medium model represents the extra cellular scaffold and the interstitial fluid flow, while a surface-bound transport model accounts for the diffusion and reaction of membrane-bound chemical species. By further modelling the volume-bound transport, we consider the advection, diffusion and reaction of sequestered chemical species within the extracellular scaffold. The chemo-mechanical coupling is established by introducing a continuum formulation for the interplay of reaction rates and the mechanical state of the ECM. It is based on known experimental insights and theoretical work on the thermodynamics of porous media and degradation kinetics of collagen fibres on the one hand and a damage-like effect of the fibre dissolution on the mechanical integrity of the ECM on the other hand. The resulting system of partial differential equations is solved via the finite-element method. To the best of our knowledge, it is the first computational model including contemporaneously the coupling between (i) advection-diffusion-reaction processes, (ii) interstitial flow and deformation of a porous medium, and (iii) the chemo-mechanical interaction impelled by the dissolution of the ECM. Our numerical examples show good agreement with experimental data. Furthermore, we outline the capability of the methodology to extend existing numerical approaches towards a more comprehensive model for cellular biochemo-mechanics.

4.
J Phys Condens Matter ; 29(15): 155304, 2017 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-28181915

RESUMO

AA-stacked graphite and closely related structures, where carbon atoms are located in registry in adjacent graphene layers, are a feature of graphitic systems including twisted and folded bilayer graphene, and turbostratic graphite. We present the results of ab initio density functional theory calculations performed to investigate the complexes that are formed from the binding of vacancy defects across neighbouring layers in AA-stacked bilayers. As with AB stacking, the carbon atoms surrounding lattice vacancies can form interlayer structures with sp 2 bonding that are lower in energy than in-plane reconstructions. The sp 2 interlayer bonding of adjacent multivacancy defects in registry creates a type of stable sp 2 bonded 'wormhole' or tunnel defect between the layers. We also identify a new class of 'mezzanine' structure characterised by sp 3 interlayer bonding, resembling a prismatic vacancy loop. The V 6 hexavacancy variant, where six sp 3 carbon atoms sit midway between two carbon layers and bond to both, is substantially more stable than any other vacancy aggregate in AA-stacked layers. Our focus is on vacancy generation and aggregation in the absence of extreme temperatures or intense beams.

5.
J Perinatol ; 37(4): 369-374, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28102854

RESUMO

OBJECTIVE: The Institute of Medicine (IOM) 2009 gestational weight gain (GWG) guidelines are based on prepregnancy body mass index (BMI) categories. We intended to refine optimal GWG for each prepregnancy BMI unit in relation to the risk of small- and large-for-gestational-age (SGA and LGA) births, cesarean section (C-section) and infant death. STUDY DESIGN: We used data from 836,841 Ohio birth records from 2006 to 2012, and applied generalized additive models to calculate optimal GWG by prepregnancy BMI unit. RESULTS: The suggested optimal GWG was generally similar to IOM 2009 GWG guidelines for prepregnancy BMIs <25 kg m-2, but higher for prepregnancy BMIs 25 to 32 kg m-2 and lower for BMIs 38 to 50 kg m-2. The suggested optimal GWG was 14 to 18.5, 13 to 17, 11.5 to 16, 8.5 to 12.5, 4 to 10, 3 to 7, 1.5 to 6 and 1.5 to 4.5 kg for prepregnancy BMIs 15, 20, 25, 30, 35, 40, 45 and 50 kg m-2, respectively. CONCLUSION: This research suggests that GWG recommendations may be refined at individual prepregnancy BMI levels.


Assuntos
Índice de Massa Corporal , Obesidade/epidemiologia , Complicações na Gravidez/epidemiologia , Resultado da Gravidez , Aumento de Peso/fisiologia , Adulto , Declaração de Nascimento , Cesárea/estatística & dados numéricos , Feminino , Humanos , Recém-Nascido , Recém-Nascido Pequeno para a Idade Gestacional , Masculino , Obesidade/complicações , Ohio/epidemiologia , Gravidez , Análise de Regressão , Adulto Jovem
6.
J Chemother ; 26(3): 150-3, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24090971

RESUMO

BACKGROUND: The use of carbapenem antibacterials in patients with a claimed history of penicillin allergy is somewhat controversial. This study aimed to examine the rates of presumed hypersensitivity reactions in a large cohort of patients receiving carbapenem antibiotics. METHODS: A retrospective chart review was performed on all adult patients who received a carbapenem in a teaching hospital from June 2011 to June 2012. Information procured included listed penicillin allergy and reaction if known, type of carbapenem received, and any allergic reaction during that admission. RESULTS: Nine-hundred and fifty eight patients who received a carbapenem antimicrobial were reviewed. Five patients developed a presumed reaction to carbapenem: one in the penicillin allergy group and four in the non-allergic group. There were no statistical or numerical differences in rates of reaction between the two groups. CONCLUSION: Patients with a claimed history of penicillin allergy were not more likely to develop a presumed hypersensitivity reaction to a carbapenem compared to those who did not claim such an allergy.


Assuntos
Carbapenêmicos/efeitos adversos , Hipersensibilidade a Drogas/epidemiologia , Hipersensibilidade a Drogas/etiologia , Penicilinas/efeitos adversos , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
7.
Neurology ; 65(11): 1737-43, 2005 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-16344515

RESUMO

OBJECTIVE: To evaluate the efficacy and tolerability of adjunctive lamotrigine in primary generalized tonic-clonic (PGTC) seizures in a randomized, double-blind, placebo-controlled trial. METHODS: Patients with a diagnosis of epilepsy with PGTC seizures who were receiving one or two antiepileptic drugs at study entry were eligible. Patients with partial seizures were excluded on the basis of seizure history and screening EEGs. The study comprised a baseline phase, an escalation phase during which study medication was titrated to a target dose, and a 12-week maintenance phase during which doses of lamotrigine/placebo and concomitant antiepileptic drugs were maintained. RESULTS: Of the 121 randomized patients ages 2 to 55 years, 117 (58 lamotrigine, 59 placebo) entered the escalation phase and received study medication. During the escalation and maintenance phases combined, median percent reduction in PGTC seizure frequency was 66.5% with lamotrigine compared with 34.2% with placebo (p = 0.006). The corresponding numbers for lamotrigine and placebo were 60.6% and 32.8% (p = 0.038) during the escalation phase and 81.9% and 43.0% (p = 0.006) during the maintenance phase. During the maintenance phase, 72% of lamotrigine-treated patients compared with 49% of placebo-treated patients experienced a > or = 50% reduction in frequency of PGTC seizures (p = 0.014). A similar pattern of results was observed for all generalized seizures. The most common drug-related adverse events were dizziness (5% lamotrigine, 2% placebo), somnolence (5% lamotrigine, 2% placebo), and nausea (5% lamotrigine, 3% placebo). CONCLUSIONS: Adjunctive lamotrigine is effective in the treatment of primary generalized tonic-clonic seizures and has a favorable tolerability profile.


Assuntos
Anticonvulsivantes/administração & dosagem , Epilepsia Tônico-Clônica/tratamento farmacológico , Triazinas/administração & dosagem , Adolescente , Adulto , Anticonvulsivantes/efeitos adversos , Criança , Pré-Escolar , Distúrbios do Sono por Sonolência Excessiva/induzido quimicamente , Tontura/induzido quimicamente , Relação Dose-Resposta a Droga , Método Duplo-Cego , Eletroencefalografia , Epilepsia Tônico-Clônica/fisiopatologia , Feminino , Humanos , Lamotrigina , Masculino , Pessoa de Meia-Idade , Náusea/induzido quimicamente , Seleção de Pacientes , Placebos , Resultado do Tratamento , Triazinas/efeitos adversos
8.
Epilepsy Behav ; 4(4): 386-94, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12899858

RESUMO

This study evaluated the effects of lamotrigine as adjunctive therapy for refractory epilepsy in patients with mental retardation. Patients with epilepsy and mental retardation having uncontrolled seizures despite treatment with other antiepileptic drugs were eligible (n=67). The open-label study comprised a Baseline Phase, an Escalation Phase during which lamotrigine was titrated to a target dose, an 8-week Maintenance Phase during which doses of lamotrigine and concomitant antiepileptic drugs were maintained, and a 12-week Optimization Phase during which doses of lamotrigine and other antiepileptic drugs could be adjusted. Almost half (44%) of patients experienced a 50% reduction in seizure frequency during the Maintenance Phase after addition of lamotrigine; 15% of patients became seizure-free. A similar pattern of results was reported for the Optimization Phase. Investigator-rated clinical status was improved relative to baseline in 66 and 74% of patients at the end of the Maintenance and Optimization Phases, respectively. Most patients experienced improvements in seizure frequency, duration, and intensity during the Maintenance Phase (62 to 72%) and the Optimization Phase (65 to 74%). Many patients were rated as having improved social functioning during the Maintenance Phase (42%) and the Optimization Phase (46%). The Aberrant Behavior Checklist score for lethargy and the mean Habilitative Improvement Scale score were improved at the ends of the Maintenance and Optimization Phases relative to baseline (P< or =0.04). One limitation of this study is its open-label design, which limits the ability definitively to attribute the clinical improvements to lamotrigine. Adjunctive lamotrigine in patients with refractory epilepsy and mental retardation appears to decrease seizure frequency and improve behavior while permitting a reduction in dose of concomitant antiepileptic drugs.


Assuntos
Anticonvulsivantes/uso terapêutico , Epilepsia/tratamento farmacológico , Deficiência Intelectual/tratamento farmacológico , Triazinas/uso terapêutico , Adolescente , Adulto , Quimioterapia Combinada , Epilepsia/complicações , Feminino , Humanos , Deficiência Intelectual/complicações , Lamotrigina , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
9.
Neurology ; 56(2): 172-7, 2001 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-11160951

RESUMO

OBJECTIVE: To compare the incidence and magnitude of change in body weight associated with lamotrigine or divalproex sodium monotherapy in patients with epilepsy. METHODS: A randomized, double-blind study with 8-week escalation phase and 24-week maintenance phase was conducted. Target maintenance dosage was 200 mg/day (lamotrigine) and 20 mg/kg/day (valproic acid), with adjustment from 100 to 500 mg/day (lamotrigine) and 10 to 60 mg/kg/day (valproate) based on investigators' judgment. Eligible patients were > or = 12 years old with new-onset or previously diagnosed partial or generalized seizures. Weight change was primary and seizure frequency and tolerance were secondary outcome measures. RESULTS: For the lamotrigine group, 65 patients (mean age 34.5 years) were investigated; for the valproate group, 68 patients (mean age 30.1 years) were investigated. Weight remained stable in lamotrigine-treated patients. Significant weight gain occurred in valproate-treated patients by the 10th week of treatment; weight continued to increase throughout the study. After 32 weeks of treatment, mean weight gain was significantly higher in valproate-treated (12.8 +/- 9.3 lb) than lamotrigine-treated (1.3 +/- 11.9 lb) patients. Similar proportions of patients in lamotrigine (29%) and valproate (26%) groups were seizure-free. Overall frequency of adverse events was similar between the two treatment groups. Mean time to withdrawal from the study due to adverse events was 103 +/- 70 days for the lamotrigine group and 79 +/- 48 days for the valproate group. CONCLUSION: Valproate monotherapy was associated with significantly greater weight gain than lamotrigine monotherapy. Weight gain associated with valproate was significant within 10 weeks after initiating therapy and continued throughout the study. Efficacy of lamotrigine was comparable with that of valproate; lamotrigine tended to be better tolerated.


Assuntos
Anticonvulsivantes/uso terapêutico , Peso Corporal/efeitos dos fármacos , Epilepsia/tratamento farmacológico , Epilepsia/fisiopatologia , Triazinas/uso terapêutico , Ácido Valproico/uso terapêutico , Adolescente , Adulto , Idoso , Peso Corporal/fisiologia , Criança , Feminino , Humanos , Lamotrigina , Masculino , Pessoa de Meia-Idade
10.
Neurology ; 54(4): 973-5, 2000 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-10690996

RESUMO

A side effect associated with the use of some antiepileptic drugs (AEDs) is change in body weight. To evaluate the effect of lamotrigine on body weight in adult patients with epilepsy, we conducted a retrospective review of data from 463 patients treated with lamotrigine in 32 clinical trials. Mean daily dose was 259 (+/-155) mg and duration of therapy was 318 (+/-87) days. The mean change in body weight was 0.5 (+/-5) kg. Lamotrigine was associated with stable body weight in patients with epilepsy.


Assuntos
Peso Corporal/fisiologia , Epilepsia/tratamento farmacológico , Epilepsia/fisiopatologia , Triazinas/uso terapêutico , Adulto , Peso Corporal/efeitos dos fármacos , Feminino , Humanos , Lamotrigina , Masculino
11.
J Med Chem ; 39(3): 713-9, 1996 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-8576914

RESUMO

Eleven water soluble 7-substituted quaternary ammonium salt derivatives of 10,11-(methylenedioxy)- and 10,11-(ethylenedioxy)-(20S)-camptothecin were synthesized via the Friedlander reaction followed by nucleophilic displacement with an aromatic amine. All of these compounds were more potent than camptothecin in the in vitro cleavable complex assay. These inherently charged camptothecin derivatives were cytotoxic against three different human tumor cell lines (SKOV3, an ovarian adenocarcinoma; SKVLB a multidrug resistant ovarian adenocarcinoma; and HT-29, a colon carcinoma). A selected group of five compounds was evaluated in the nude mouse HT-29 xenograft model. Two of these quaternary salts (17 and 18) were more efficacious than Topotecan in delaying tumor growth. In an extended in vivo model, 18 demonstrated tumor regression.


Assuntos
Antineoplásicos/farmacologia , Camptotecina/farmacologia , Inibidores da Topoisomerase I , Adenocarcinoma/enzimologia , Adenocarcinoma/patologia , Animais , Antineoplásicos/química , Camptotecina/análogos & derivados , Neoplasias do Colo/enzimologia , Neoplasias do Colo/patologia , Feminino , Humanos , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Camundongos , Camundongos Nus , Neoplasias Ovarianas/enzimologia , Neoplasias Ovarianas/patologia , Solubilidade , Relação Estrutura-Atividade , Células Tumorais Cultivadas , Água
12.
Cancer Res ; 55(3): 603-9, 1995 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-7834631

RESUMO

The development of camptothecin-like compounds as inhibitors of topoisomerase I for the treatment of resistant tumors has generated clinical excitement in this new class of drugs. We have developed two novel water-soluble camptothecin analogues which are specific inhibitors of topoisomerase I and are potent cytotoxins with significant antitumor activity. We added water-solubilizing groups off position 7 in the B ring of either 10,11-ethylenedioxy- or 10,11-methylenedioxy-20(S)-camptothecin. These water-soluble camptothecin analogues were demonstrated to be nanamolar inhibitors of the topoisomerase I enzyme in the cleavable complex assay. The compounds, GI147211 [7-(4-methylpiperazinomethylene)-10,11-ethylenedioxy-20(S)-camp tot hecin], and GI149893 [7-(4-methylpiperazinomethylene)-10,11-methylenedioxy-20(S)-cam pto thecin], were compared to topotecan, a known water-soluble inhibitor of topoisomerase I. Both GI compounds were found to be slightly more potent than topotecan as inhibitors of topoisomerase I in the cleavable complex assay and were 1.5-2 times more soluble. Tumor cell cytotoxicity assays using 5 separate cell lines demonstrated that both GI compounds were 5-10 times more potent than topotecan, although by comparison all three topoisomerase I inhibitors were unaffected by the multidrug resistance P-glycoprotein. The antitumor activity of all three topoisomerase I inhibitors was compared concomitantly in two human colon xenograft models. In both models, GI147211 and GI149893 were able to induce regression of established HT-29 and SW-48 colon tumors by as much as 60%. The antitumor activity of both compounds were also demonstrated in the MX-1 and PC-3 xenografts. Microscopic examination of selected tissues indicated that drug-induced toxicity was primarily limited to the gastrointestinal tract and was comparable among the three compounds. Further clinical development of this class of compounds is ongoing.


Assuntos
Antineoplásicos/uso terapêutico , Camptotecina/análogos & derivados , Neoplasias do Colo/tratamento farmacológico , Inibidores da Topoisomerase I , Animais , Antineoplásicos/toxicidade , Peso Corporal/efeitos dos fármacos , Camptotecina/uso terapêutico , Camptotecina/toxicidade , Bovinos , Divisão Celular/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Neoplasias do Colo/patologia , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Camundongos , Camundongos Nus , Timo/enzimologia , Topotecan , Transplante Heterólogo , Células Tumorais Cultivadas
13.
J Pharmacol Exp Ther ; 263(1): 84-91, 1992 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1403806

RESUMO

Hemodynamic effects of GI 87084B, a novel ultra-short acting mu-opioid agonist, were studied in anesthetized dogs. In these studies, GI 87084B (0.3-20 nmol/kg/min i.v.) produced dose-dependent decreases in heart rate, arterial blood pressure, +dP/dt and cardiac output. Alfentanil produced similar effects but was less potent. After termination of the infusions (397 nmol/kg cumulative dose), the hemodynamic effects of GI 87084B dissipated over 30 to 40 min. The effects of alfentanil, however, persisted throughout the 60-min recovery period. Infusion of GI 87084B at lower dose rates (0.001-0.3 nmol/kg/min) in barbiturate-anesthetized dogs showed a threshold dose of 0.1 to 0.3 nmol/kg/min for effects on hemodynamic variables. After infusing 0.3 nmol/kg/min of GI 87084B for 10 min, hemodynamic variables recovered rapidly (10-20 min). Boli of GI 87084B (0.3-100 nmol/kg i.v.) produced dose-dependent decreases in the same hemodynamic variables. The duration of these effects increased from 5 to 20 min at 3 nmol/kg to 15 to 45 min at 100 nmol/kg. Naloxone (0.063 mg/kg/hr) decreased the magnitude and duration of the effects of GI 87084B, suggesting that these effects are mediated through opioid receptors. In summary, GI 87084B produced hemodynamic effects consistent with mu-opioid agonism when administered by infusion or bolus, but these effects were brief in duration compared to other opioids.


Assuntos
Hemodinâmica/efeitos dos fármacos , Piperidinas/farmacologia , Alfentanil/farmacologia , Analgésicos/farmacologia , Animais , Cães , Relação Dose-Resposta a Droga , Feminino , Infusões Intravenosas , Masculino , Remifentanil
14.
Life Sci ; 38(21): 1967-74, 1986 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-2872565

RESUMO

The cardiodynamic activity of intravenously administered milrinone was examined in alpha-chloralose anesthetized dogs. Two groups of dogs were used, one pretreated with hexamethonium to block autonomic reflexes, and a second group which received no pretreatment. In the untreated group milrinone produced dose-dependent increases in +dP/dt and heart rate while decreasing both systolic and diastolic blood pressure and left ventricular end diastolic pressure (LVEDP). After treatment with hexamethonium basal heart rate was significantly increased, whereas reflex changes in heart rate in response to i.v. norepinephrine or nitroglycerin were ablated. Systolic, but not diastolic blood pressure was also markedly reduced by hexamethonium. In the presence of hexamethonium responses to milrinone were qualitatively similar to milrinone responses in the absence of hexamethonium. However, the dose-response curves for milrinone were shifted dextrally for changes in +dP/dt and LVEDP, whereas the dose-response curve for blood pressure was shifted sinistrally. Thus, it appears that the autonomic nervous system enhances the effect of milrinone on +dP/dt and LVEDP, but attenuates its effect on blood pressure.


Assuntos
Sistema Nervoso Autônomo/fisiologia , Fenômenos Fisiológicos Cardiovasculares , Piridonas/farmacologia , Animais , Sistema Nervoso Autônomo/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Sistema Cardiovascular/efeitos dos fármacos , Diástole/efeitos dos fármacos , Cães , Relação Dose-Resposta a Droga , Feminino , Frequência Cardíaca/efeitos dos fármacos , Hexametônio , Compostos de Hexametônio/farmacologia , Masculino , Milrinona , Nitroglicerina/farmacologia , Norepinefrina/farmacologia , Pressão , Sístole/efeitos dos fármacos , Função Ventricular
15.
J Cardiovasc Pharmacol ; 6(4): 555-64, 1984.
Artigo em Inglês | MEDLINE | ID: mdl-6206307

RESUMO

The beta-adrenergic receptor blocking properties of ACC-9089 were studied in isolated cardiac and tracheal tissues from guinea pigs and in anesthetized dogs. The compound was a potent, nonselective beta-blocker in isolated tissues (atrial pA2 8.01; tracheal pA2 8.16). ACC-9089 was without intrinsic sympathomimetic action and caused direct cardiac depression only at concentrations that were four orders of magnitude higher than its pA2. In anesthetized dogs, ACC-9089 produced steady-state beta-blockade within 20 min of initiation of 3-h intravenous infusions. Recovery from beta-blockade occurred rapidly following termination of infusion (80% recovery in 17 +/- 2 min after 1.2 microgram/kg/min). Intravenous infusion of ACC-9089 caused dose-dependent inhibition of heart rate responses to sympathetic nerve stimulation and inhibition of isoproterenol-induced decreases in perfusion pressure in a perfused hindlimb preparation. The compound (a) did not produce alpha-blockade; (b) had no direct effect on hindlimb vascular resistance; and (c) did not alter hemodynamic variables in catecholamine-depleted dogs. The results indicate that ACC-9089 is a novel, ultra-short-acting beta-blocker that does not possess direct cardiovascular effects beyond those expected as a result of beta-blockade.


Assuntos
Antagonistas Adrenérgicos beta/farmacologia , Fluorbenzenos , Hemodinâmica/efeitos dos fármacos , Propanolaminas/farmacologia , Animais , Catecolaminas/fisiologia , Cães , Estimulação Elétrica , Feminino , Cobaias , Coração/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Membro Posterior/irrigação sanguínea , Técnicas In Vitro , Isoproterenol/farmacologia , Masculino , Contração Muscular/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , Norepinefrina/farmacologia , Propranolol/farmacologia , Fluxo Sanguíneo Regional/efeitos dos fármacos
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