RESUMEN
We report the first measurement of the parity-violating elastic electron scattering asymmetry on ^{27}Al. The ^{27}Al elastic asymmetry is A_{PV}=2.16±0.11(stat)±0.16(syst) ppm, and was measured at ⟨Q^{2}⟩=0.02357±0.00010 GeV^{2}, ⟨θ_{lab}⟩=7.61°±0.02°, and ⟨E_{lab}⟩=1.157 GeV with the Q_{weak} apparatus at Jefferson Lab. Predictions using a simple Born approximation as well as more sophisticated distorted-wave calculations are in good agreement with this result. From this asymmetry the ^{27}Al neutron radius R_{n}=2.89±0.12 fm was determined using a many-models correlation technique. The corresponding neutron skin thickness R_{n}-R_{p}=-0.04±0.12 fm is small, as expected for a light nucleus with a neutron excess of only 1. This result thus serves as a successful benchmark for electroweak determinations of neutron radii on heavier nuclei. A tree-level approach was used to extract the ^{27}Al weak radius R_{w}=3.00±0.15 fm, and the weak skin thickness R_{wk}-R_{ch}=-0.04±0.15 fm. The weak form factor at this Q^{2} is F_{wk}=0.39±0.04.
RESUMEN
A beam-normal single-spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable related to the imaginary part of the two-photon exchange process. We report a 2% precision measurement of the beam-normal single-spin asymmetry in elastic electron-proton scattering with a mean scattering angle of θ_{lab}=7.9° and a mean energy of 1.149 GeV. The asymmetry result is B_{n}=-5.194±0.067(stat)±0.082 (syst) ppm. This is the most precise measurement of this quantity available to date and therefore provides a stringent test of two-photon exchange models at far-forward scattering angles (θ_{lab}â0) where they should be most reliable.
RESUMEN
In 2017, potato tubers suspected of being infected with the bacterium 'Candidatus Liberibacter solanacearum' were received from the Animal and Plant Health Inspection Service in the United States. A total of 368 chipping tubers were observed for internal symptoms of zebra chip disease, which is associated with 'Ca. L. solanacearum' infection in the United States, Mexico, Central America, and New Zealand. A single tuber sliced at the stem end showed classic zebra chip symptoms of darkened medullary rays, with streaking and necrotic flecking. The symptomatic tuber was confirmed positive for the bacterium by polymerase chain reaction targeting three different 'Ca. L. solanacearum' genes. Sequence analysis of these three genes, and subsequent BLAST analysis, identified the pathogen with 99, 98, and 97% identity to 'Ca. L. solanacearum' for the 16S ribosomal RNA gene, 50S ribosomal proteins L10/L12 genes, and the outer membrane protein gene, respectively. Sequence analysis did not identify the sample as one of the six known haplotypes of 'Ca. L. solanacearum,' indicating that a seventh haplotype of the pathogen was identified. This new haplotype, designated haplotype F, is now the third haplotype of the bacterium that infects Solanum tuberosum in the United States.
Asunto(s)
Haplotipos , Rhizobiaceae , Solanum tuberosum , Animales , Genes Bacterianos/genética , Enfermedades de las Plantas/microbiología , Rhizobiaceae/clasificación , Rhizobiaceae/genética , Solanum tuberosum/microbiologíaRESUMEN
A number of rare cardiac diseases can be recognized by electrocardiogram (ECG). This article illustrates the clinical importance of ECG as a key diagnostic tool to detect Wolff-Parkinson-White syndrome and channelopathies, which are frequently diagnosed late after one or more affected family members have become victims of sudden cardiac death. These channelopathies include long QT syndrome, short QT syndrome, Brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia. In addition, typical ECG findings are frequently present in patients with idiopathic ventricular tachycardia, arrhythmogenic right ventricular dysplasia, digitalis intoxication, hyperkalemia, acute cor pulmonale due to pulmonary embolism, as well as severe left ventricular hypertrophy as in hypertrophic cardiomyopathy.
Asunto(s)
Síndrome de Brugada , Electrocardiografía , Síndrome de QT Prolongado , Taquicardia Ventricular , Arritmias Cardíacas/diagnóstico , Síndrome de Brugada/diagnóstico , Muerte Súbita Cardíaca , Humanos , Síndrome de QT Prolongado/diagnóstico , Taquicardia Ventricular/diagnósticoRESUMEN
BACKGROUND: The public health, public safety and clinical implications of violent events among adults with mental illness are significant; however, the causes and consequences of violence and victimization among adults with mental illness are complex and not well understood, which limits the effectiveness of clinical interventions and risk management strategies. This study examined interrelationships between violence, victimization, psychiatric symptoms, substance use, homelessness and in-patient treatment over time. METHOD: Available data were integrated from four longitudinal studies of adults with mental illness. Assessments took place at baseline, and at 1, 3, 6, 9, 12, 15, 18, 24, 30 and 36 months, depending on the parent studies' protocol. Data were analysed with the autoregressive cross-lag model. RESULTS: Violence and victimization were leading indicators of each other and affective symptoms were a leading indicator of both. Drug and alcohol use were leading indicators of violence and victimization, respectively. All psychiatric symptom clusters - affective, positive, negative, disorganized cognitive processing - increased the likelihood of experiencing at least one subsequent symptom cluster. Sensitivity analyses identified few group-based differences in the magnitude of effects in this heterogeneous sample. CONCLUSIONS: Violent events demonstrated unique and shared indicators and consequences over time. Findings indicate mechanisms for reducing violent events, including trauma-informed therapy, targeting internalizing and externalizing affective symptoms with cognitive-behavioral and psychopharmacological interventions, and integrating substance use and psychiatric care. Finally, mental illness and violence and victimization research should move beyond demonstrating concomitant relationships and instead focus on lagged effects with improved spatio-temporal contiguity.
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Víctimas de Crimen/estadística & datos numéricos , Hospitalización/estadística & datos numéricos , Personas con Mala Vivienda/estadística & datos numéricos , Trastornos Mentales/epidemiología , Violencia/estadística & datos numéricos , Adulto , Humanos , Trastornos Mentales/terapiaRESUMEN
The Q(weak) experiment has measured the parity-violating asymmetry in ep elastic scattering at Q(2)=0.025(GeV/c)(2), employing 145 µA of 89% longitudinally polarized electrons on a 34.4 cm long liquid hydrogen target at Jefferson Lab. The results of the experiment's commissioning run, constituting approximately 4% of the data collected in the experiment, are reported here. From these initial results, the measured asymmetry is A(ep)=-279±35 (stat) ± 31 (syst) ppb, which is the smallest and most precise asymmetry ever measured in ep scattering. The small Q(2) of this experiment has made possible the first determination of the weak charge of the proton Q(W)(p) by incorporating earlier parity-violating electron scattering (PVES) data at higher Q(2) to constrain hadronic corrections. The value of Q(W)(p) obtained in this way is Q(W)(p)(PVES)=0.064±0.012, which is in good agreement with the standard model prediction of Q(W)(p)(SM)=0.0710±0.0007. When this result is further combined with the Cs atomic parity violation (APV) measurement, significant constraints on the weak charges of the up and down quarks can also be extracted. That PVES+APV analysis reveals the neutron's weak charge to be Q(W)(n)(PVES+APV)=-0.975±0.010.
RESUMEN
We report on parity-violating asymmetries in the nucleon resonance region measured using inclusive inelastic scattering of 5-6 GeV longitudinally polarized electrons off an unpolarized deuterium target. These results are the first parity-violating asymmetry data in the resonance region beyond the Δ(1232). They provide a verification of quark-hadron duality-the equivalence of the quark- and hadron-based pictures of the nucleon-at the (10-15)% level in this electroweak observable, which is dominated by contributions from the nucleon electroweak γZ interference structure functions. In addition, the results provide constraints on nucleon resonance models relevant for calculating background corrections to elastic parity-violating electron scattering measurements.
RESUMEN
To determine the spread of Staphylococcus aureus within and between nursing home (NH) residents in the Euregion Meuse-Rhine, a cross-border region of the Netherlands and Germany, we investigated the prevalence of antibiotic resistance, genetic background and population structure of both methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) isolates. A total of 245 S. aureus isolates were collected from NH residents. Susceptibility testing was performed with microbroth dilution. The genetic background was determined using spa typing, SCCmec typing, pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Differences in the prevalence of resistance between the German and Dutch MSSA isolates were observed for the macrolides (15 % vs. 2 %, p = 0.003), clindamycin (15 % vs. 0 %, p = 0.003) and ciprofloxacin (34 % vs. 25 %). The macrolide and ciprofloxacin resistance varied between the NHs, while trimethoprim-sulfamethoxazole resistance was low in all residents. The MRSA prevalence was 3.5 % and <1 % among the German and Dutch NH residents, respectively (p = 0.005). The German MRSAs, isolated in 7 out of 10 NHs, belonged to ST22-MRSA-IV or ST225-MRSA-II. spa clonal complexes (spa-CCs) 015 and 002 were prevalent among the German MSSA isolates and spa-CCs 024 and 1716 were prevalent among the Dutch MSSA isolates. The antibiotic resistance of MSSA and the MRSA prevalence were significantly higher among the German NH residents. The spread of two MRSA clones was observed within and between the German NHs, but not between the Dutch and German NHs. Differences in the prevalence of resistance and the prevalence of MRSA between NHs on both sides of the border warrant the continuation of surveillance at a local level.
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Infección Hospitalaria/epidemiología , Farmacorresistencia Bacteriana , Casas de Salud , Infecciones Estafilocócicas/epidemiología , Staphylococcus aureus/clasificación , Staphylococcus aureus/efectos de los fármacos , Antibacterianos/farmacología , Infección Hospitalaria/microbiología , Farmacorresistencia Microbiana , Genotipo , Alemania/epidemiología , Humanos , Pruebas de Sensibilidad Microbiana , Epidemiología Molecular , Tipificación Molecular , Países Bajos/epidemiología , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/genética , Staphylococcus aureus/aislamiento & purificaciónRESUMEN
The parity-violating cross-section asymmetry in the elastic scattering of polarized electrons from unpolarized protons has been measured at a four-momentum transfer squared Q2 = 0.624 GeV2 and beam energy E(b) = 3.48 GeV to be A(PV) = -23.80 ± 0.78(stat) ± 0.36(syst) parts per million. This result is consistent with zero contribution of strange quarks to the combination of electric and magnetic form factors G(E)(s) + 0.517G(M)(s) = 0.003 ± 0.010(stat) ± 0.004(syst) ± 0.009(ff), where the third error is due to the limits of precision on the electromagnetic form factors and radiative corrections. With this measurement, the world data on strange contributions to nucleon form factors are seen to be consistent with zero and not more than a few percent of the proton form factors.
RESUMEN
The electric form factor of the neutron was determined from studies of the reaction 3He(e,e'n)pp in quasielastic kinematics in Hall A at Jefferson Lab. Longitudinally polarized electrons were scattered off a polarized target in which the nuclear polarization was oriented perpendicular to the momentum transfer. The scattered electrons were detected in a magnetic spectrometer in coincidence with neutrons that were registered in a large-solid-angle detector. More than doubling the Q2 range over which it is known, we find G(E)(n)=0.0236±0.0017(stat)±0.0026(syst), 0.0208±0.0024±0.0019, and 0.0147±0.0020±0.0014 for Q(2)=1.72, 2.48, and 3.41 GeV2, respectively.
RESUMEN
Regimen selection in antiretroviral therapy can impact treatment adherence, quality of life (QoL) and treatment satisfaction, and may influence clinical outcome. We evaluated the effect of regimen switching on virological, safety and patient-reported outcomes. In this 48-week, open-label, randomized, non-inferiority study, 262 HIV-1-infected adult patients with a viral load <50 copies/mL on protease inhibitor (PI)-based regimens were switched to either once-daily efavirenz, lamivudine and enteric-coated didanosine (efavirenz-A [QD]) or once-daily efavirenz plus continuation of current nucleoside reverse transcriptase inhibitors (efavirenz-B). In the primary outcome of patients who maintained virological suppression at week 48, efavirenz-A (QD) was non-inferior to efavirenz-B (81% versus 79%, respectively). Both regimens were associated with low virological failure rates and significant improvements in treatment satisfaction, adherence and QoL after switching from PI-based therapy, with no differences between regimens. Switching from a PI- to an efavirenz-based regimen was generally safe and well tolerated.
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Benzoxazinas/uso terapéutico , Infecciones por VIH/tratamiento farmacológico , Inhibidores de la Proteasa del VIH/uso terapéutico , VIH-1 , Inhibidores de la Transcriptasa Inversa/uso terapéutico , Adulto , Alquinos , Terapia Antirretroviral Altamente Activa , Recuento de Linfocito CD4 , Ciclopropanos , Didanosina/uso terapéutico , Femenino , Infecciones por VIH/inmunología , Infecciones por VIH/virología , Humanos , Lamivudine/uso terapéutico , Masculino , Cooperación del Paciente , Satisfacción del Paciente , Calidad de Vida , Resultado del Tratamiento , Estados Unidos , Carga ViralAsunto(s)
Lesión Renal Aguda , Enfermedades de los Gatos , Tiazinas , Gatos , Animales , Meloxicam/uso terapéutico , Antiinflamatorios no Esteroideos/efectos adversos , Australia/epidemiología , Lesión Renal Aguda/inducido químicamente , Lesión Renal Aguda/veterinaria , Tiazinas/efectos adversos , Enfermedades de los Gatos/inducido químicamente , Enfermedades de los Gatos/tratamiento farmacológicoRESUMEN
BACKGROUND AND OBJECTIVES: Glucocorticosteroids are widely used in medicine and have shown unchallenged therapeutic potential in several chronic inflammatory and other diseases. They are also widely used in sports medicine for the treatment of conditions such as asthma and acute injuries. In fact, as banned substances, most requests for therapeutic use exemption concern glucocorticosteroids. Nevertheless, their beneficial effect in certain conditions in sports, where inflammation is only a secondary reaction, remains to be validated. This paper aimed to provide a comprehensive review of the literature covering the therapeutic use of glucocorticosteroids since 1977 in conditions ranging from chronic rheumatic illness to peritendinous or intra-articular injection in acute injuries. METHODS: Search of the medical literature published between 1977 and 2006 using PubMed. Articles relevant to the question "When and if at all is the use of glucocorticosteroids justified in football?" were selected and analysed. RESULTS AND CONCLUSIONS: The findings clearly point out that, despite the common use of glucocorticosteroids in acute injuries in sports, there is actually limited evidence of the true benefits of such a practice. Physicians must take the possible adverse effects into consideration. In an athlete with clinically verified asthma, inhalational glucocorticosteroids remain first line therapy. Finally, for the purposes of education and prevention of misuse, it should be stressed that a measurable performance enhancing effect of glucocorticoids could not be proved on the basis of the results of the scientific studies to date.
Asunto(s)
Traumatismos en Atletas/tratamiento farmacológico , Doping en los Deportes/prevención & control , Glucocorticoides/administración & dosificación , Fútbol/lesiones , Glucocorticoides/farmacocinética , HumanosRESUMEN
BACKGROUND AND METHODS: Differences in newborn outcome measures for human immunodeficiency virus (HIV)-1-infected and HIV-1-exposed but uninfected infants have been found in several studies, but not in others. Eighty-four infected and 248 uninfected children born to HIV-1-seropositive mothers followed prospectively in a multicenter, perinatal HIV-1 transmission cohort study were compared for differences in maternal demographics, health status, and newborn outcome measures, including delivery complications, physical examination findings, neonatal complications, and laboratory results. RESULTS: Mothers of HIV-1-infected infants were more likely than those of uninfected infants to have acquired immunodeficiency syndrome (AIDS) diagnosed through 2 weeks postpartum (21% vs 11%, P = .04); the transmission rate for the 38 women with AIDs was 37% compared with 22% for the 245 women without AIDS. Two of 27 (7%) women receiving zidovudine during pregnancy had infected infants compared with 73 (27%) of 275 women who did not receive zidovudine (P = .033). Mean gestational age was significantly lower among HIV-1-infected (37 weeks) than among uninfected infants (38 weeks; P < .001). Infected infants had significantly higher rates of prematurity (gestational age less than 37 weeks) (33% vs 19%, P = .01) and extreme prematurity (gestational age less than 34 weeks) (18% vs 6%, P = .001) than uninfected infants. Infection was associated with lower birth weight (2533 g vs 2862 g, P < .001) and smaller head circumference (32.0 cm vs 33.1 cm, P = .001). HIV-1-infected infants were significantly more likely to be small for gestational age (26% vs 16%, P = .04) and low birth weight (less than 2500 g) (45% vs 29%, P = .006) than infants who were uninfected. Twenty-two (26%) HIV-1-infected children died during a median follow-up of 27.6 months (range 1.9 to 98.3 months). Prematurity was predictive of survival: by Kaplan-Meier, an estimated 55% (95% confidence interval, 31% to 72%) of preterm infected children survived to 24 months compared with 84% (95% confidence interval, 70% to 92%) of full-term infected children (P = .005). CONCLUSION: Infants born to women with AIDS are at higher risk for HIV-1 infection than are infants born to HIV-1-infected women with AIDS not yet diagnosed. Women receiving zidovudine appear less likely to transmit HIV-1 to their infants. Significantly higher rates of prematurity and intrauterine growth retardation were found among HIV-1-infected infants than among those in the uninfected, HIV-1-exposed control group. Prematurity was associated with shortened survival in HIV-1-infected infants. Measures of intrauterine growth and gestation appear to be important predictors of HIV-1 infection status for seropositive infants and of prognosis for the infected infant.
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Infecciones por VIH/transmisión , Transmisión Vertical de Enfermedad Infecciosa , Síndrome de Inmunodeficiencia Adquirida/transmisión , Adulto , Femenino , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/mortalidad , Humanos , Recién Nacido , Recien Nacido Prematuro , Enfermedades del Prematuro/mortalidad , Masculino , Madres , Estudios Prospectivos , Análisis de Supervivencia , Zidovudina/uso terapéuticoRESUMEN
Two treatment regimens for the initial treatment of acute asthma in 50 patients between the ages of 12 and 20 years seen in the emergency room were evaluated. The treatments were randomized such that 26 patients received 2.5 mg of the beta 2-agonist fenoterol by nebulizer and 24 patients received 0.3 mg of epinephrine followed by 0.75 mg of Sus-Phrine. Clinical assessment and spirometry were performed over a two-hour period. Both groups responded within ten minutes and peak improvement was reached within one hour. Peak expiratory flow and clinical score were better following fenoterol treatment in the first hour (P less than .05). The one-second forced expiratory volume and the forced expiratory flow in the middle half of the vital capacity were greater at 20 minutes with fenoterol (P less than .05). Those with more severe obstruction (forced expiratory volume less than 30%) receiving aerosol therapy also had significantly greater improvement in the first 20 minutes compared with those who received injections. Four patients failed to respond to epinephrine whereas all patients showed improvement with fenoterol (P less than .05). These results demonstrated that an inhaled beta 2-agonist is effective in the initial treatment of acute asthma in children, regardless of severity, and avoids the need for injections.
Asunto(s)
Asma/tratamiento farmacológico , Epinefrina/uso terapéutico , Etanolaminas/uso terapéutico , Fenoterol/uso terapéutico , Enfermedad Aguda , Adolescente , Adulto , Asma/diagnóstico , Presión Sanguínea , Niño , Epinefrina/efectos adversos , Femenino , Fenoterol/efectos adversos , Flujo Espiratorio Forzado , Volumen Espiratorio Forzado , Humanos , Masculino , Respiración , Capacidad VitalRESUMEN
Employers, insurers, and other purchasers of health care services collect data to profile the practice habits of pediatricians and other physicians. This policy statement delineates a series of recommendations that should be adopted by health care purchasers to guide the development and implementation of physician profiling systems.
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Benchmarking/normas , Programas Controlados de Atención en Salud/normas , Pediatría/normas , Pautas de la Práctica en Medicina , Evaluación del Rendimiento de Empleados , Humanos , Estados Unidos , Revisión de Utilización de RecursosRESUMEN
This analysis sought to identify characteristics of pregnant human immunodeficiency virus type 1 (HIV-1)-infected women that predict mother-to-child HIV-1 transmission. Pregnant and immediately postpartum women at risk for HIV were enrolled at obstetric and pediatric care settings in New York City from 1986 to 1992. Demographic and behavioral characteristics, clinical illness, T lymphocyte subsets, immunoglobulin concentration and syphilis serology were collected on the women. Infants were followed to determine HIV infection classification according to Centers for Disease Control and Prevention criteria for HIV-1 in children. Transmission rates were calculated for women who gave birth more than 15 months before the analysis. Of 172 HIV-1-infected women with known outcome 49 (28%) had infected infants. The transmission rate (TR) was significantly higher among women with < 280 CD4+ cells/microliters (lowest CD4+ quartile) than with CD4+ counts > 280 (48% vs. 22%; P = 0.004; odds ratio, 3.4; 95% confidence interval (1.5, 7.8)); a similar trend was seen by CD4+% quartile. No difference in TR was seen comparing women by CD8+ count quartile but marginally higher TR was seen among women with CD8+% > or = 51% than with CD8+% < 51% (TR = 41% vs. 24%; P = 0.076; odds ratio, 2.2; confidence interval (1.0, 5.1)). The highest TR, 62% was seen in women with both CD8+ count above the median and CD4+ count in the lowest quartile. No significant difference in TR was seen between women with and without HIV-related illness, although the TR was 53% among women hospitalized in the previous year for pneumonia compared with 25% in others (P = 0.03). TR was somewhat lower in women who delivered by cesarean section than vaginally (entire cohort: 18% vs. 32%, P = 0.11; prenatal enrollees only, 17% vs. 38%, P = 0.045). No factor or combination of factors was both highly sensitive and specific for predicting mother-to-child HIV transmission. A possible relationship between transmission and mode of delivery deserves further investigation.
Asunto(s)
Infecciones por VIH/congénito , Infecciones por VIH/transmisión , VIH-1 , Complicaciones Infecciosas del Embarazo/fisiopatología , Serodiagnóstico del SIDA , Adolescente , Adulto , Relación CD4-CD8 , Estudios de Cohortes , Femenino , Proteína p24 del Núcleo del VIH/inmunología , Infecciones por VIH/inmunología , VIH-1/inmunología , Humanos , Inmunoglobulinas/inmunología , Lactante , Recién Nacido , Embarazo , Complicaciones Infecciosas del Embarazo/inmunología , Estudios Prospectivos , Factores de Riesgo , Subgrupos de Linfocitos T/inmunologíaRESUMEN
Renal angioplasty was attempted on 38 renal arteries in 34 patients and was technically successful in 84.2%. Twenty-four patients were followed for 1 to 36 months (mean 15.3 months). The hypertension was cured or improved in 18 (75%), unchanged in 2 and recurrent after an initial period of improvement in four. Six patients were not available for further evaluation as five had additional renovascular surgery and one was lost to followup. Four patients had major complications; loss of the kidney occurred in one patient (2.9%). Respiratory renal mobility, predilatation with tapered teflon catheters and the contralateral femoral approach were found to be important technical aids for successful renal artery angioplasty.
Asunto(s)
Angioplastia de Balón/métodos , Hipertensión Renovascular/terapia , Arteria Renal , Adolescente , Adulto , Anciano , Niño , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana EdadRESUMEN
OBJECTIVE: To evaluate the cardiovascular effects of the alpha2-adrenergic receptor agonist medetomidine hydrochloride in clinically normal cats. ANIMALS: 7 clinically normal cats. PROCEDURE: Cats were anesthetized with isoflurane, and thermodilution catheters were placed for measurement of central venous, pulmonary, and pulmonary capillary wedge pressures and for determination of cardiac output. The dorsal pedal artery was catheterized for measurement of arterial blood pressures and blood gas tensions. Baseline variables were recorded, and medetomidine (20 microg/kg of body weight, IM) was administered. Hemodynamic measurements were repeated 15 and 30 minutes after medetomidine administration. RESULTS: Heart rate, cardiac index, stroke index, rate-pressure product, and right and left ventricular stroke work index significantly decreased from baseline after medetomidine administration, whereas systemic vascular resistance and central venous pressure increased. However, systolic, mean, and diastolic arterial pressures as well as arterial pH, and oxygen and carbon dioxide tensions were not significantly different from baseline values. CONCLUSIONS AND CLINICAL RELEVANCE: When administered alone to clinically normal cats, medetomidine (20 microg/kg, IM) induced a significant decrease in cardiac output, stroke volume, and heart rate. Arterial blood pressures did not increase, which may reflect a predominant central alpha2-adrenergic effect over peripheral vascular effects.
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Agonistas alfa-Adrenérgicos/farmacología , Gatos/fisiología , Hemodinámica/efectos de los fármacos , Medetomidina/farmacología , Anestésicos por Inhalación/administración & dosificación , Animales , Análisis de los Gases de la Sangre/veterinaria , Presión Sanguínea/efectos de los fármacos , Gasto Cardíaco/efectos de los fármacos , Femenino , Frecuencia Cardíaca/efectos de los fármacos , Isoflurano/administración & dosificación , MasculinoRESUMEN
OBJECTIVE: To assess duration of actions of butorphanol, medetomidine, and a butorphanol-medetomidine combination in dogs given subanesthetic doses of isoflurane (ISO). ANIMALS: 6 healthy dogs. PROCEDURE: Minimum alveolar concentration (MAC) values for ISO were determined. for each dog. Subsequently, 4 treatments were administered to each dog (saline [0.9% NaCl] solution, butorphanol [0.2 mg/kg of body weight], medetomidine [5.0 microg/kg], and a combination of butorphanol [0.2 mg/kg] and medetomidine [5.0 microg/kg]). All treatments were administered IM to dogs concurrent with isoflurane; treatment order was determined, using a randomized crossover design. Treatments were given at 7-day intervals. After mask induction with ISO and instrumentation with a rectal temperature probe, end-tidal CO2 and anesthetic gas concentrations were analyzed. End-tidal ISO concentration was reduced to 90% MAC for each dog. A tail clamp was applied 15 minutes later. After a positive response, 1 of the treatments was administered. Response to application of the tail clamp was assessed at 15-minute intervals until a positive response again was detected. RESULTS: Duration of nonresponse after administration of saline solution, butorphanol, medetomidine, and butorphanol-medetomidine (mean +/- SD) was 0.0+/-0.0, 1.5+/-1.5, 2.63+/-0.49, and 5.58+/-2.28 hours, respectively. Medetomidine effects were evident significantly longer than those for saline solution, whereas effects for butorphanol-medetomidine were evident significantly longer than for each agent administered alone. CONCLUSION AND CLINICAL RELEVANCE: During ISO-induced anesthesia, administration of medetomidine, but not butorphanol, provides longer and more consistent analgesia than does saline solution, and the combination of butorphanol-medetomidine appears superior to the use of medetomidine or butorphanol alone.