Comparação das artérias carótidas comuns de equinos e muares por ultrassonografia modo-B e Doppler espectral e a relação com a massa corpórea / Comparison of the common carotid arteries of horses and mules by B-mode and Doppler spectral ultrasonography and the relation with body mass

A ultrassonografia convencional e o Doppler espectral nas artérias carótidas comuns em equinos e muares são considerados escassos, diferentemente do que ocorre na medicina humana. Este trabalho propôs comparar as artérias carótidas comuns de equinos e muares por ultrassonografia modo-B e Doppler espectral, além de verificar as diferenças dessas variáveis entre os gêneros desses animais e a relação com a massa corpórea. Foram avaliados os seguintes parâmetros: massa corpórea, diâmetros das artérias, espessura da camada íntima-média (EIM), índice de resistividade (IR), índice de pulsatilidade (IP), velocidade sistólica (VS), velocidade diastólica (VD) e velocidade média (VM). Salvo a massa corpórea, esses parâmetros foram obtidos de três regiões (cranial, médio e caudal) e submetidos à análise conjuntamente. Os diâmetros das artérias carótidas comuns são diferentes entre equinos e muares, com valores menores nos equinos. O IR, o IP, a VS e a VM diferiram entre equinos e muares, sendo maiores nos equinos, e a VD superior nos muares. Não foi observada diferença das variáveis do modo-B e Doppler entre gêneros nos equinos, diferentemente dos muares, cujos machos apresentaram valores maiores do diâmetro, do IR e do IP, mas menores da VS e da VM. A massa corpórea não influenciou as variáveis do modo-B, independentemente do gênero, mas apresenta correlação significativa nas variáveis do modo Doppler. As artérias carótidas comuns de equinos e muares são diferentes pelos exames ultrassonográficos modo-B e Doppler espectral. O gênero não influencia no modo-B e no Doppler nos equinos, porém influencia parcialmente nos muares. A massa corpórea de equinos e de muares, independentemente do gênero, não tem associação com as variáveis do modo-B, apenas com o Doppler.(AU)

Conventional ultrasound and spectral Doppler in the common carotid arteries in horses and mules are considered scarce, different from human medicine. The aim of this study was to compare the common carotid arteries of horses and mules by B-mode ultrasonography and spectral Doppler ultrasonography, as well as to verify the differences of these variables between their genders and the relation with body mass. The following parameters were evaluated: body mass, artery diameter, intima-media thickness (EIM), resistivity index (IR), pulsatility index (IP), systolic velocity (VS), diastolic velocity (VD) and average velocity (VM). Besides the body mass, the other variables were obtained from three regions (cranial, medium and caudal) and analyzed together. The diameters of the common carotid arteries are different between horses and mules, being smaller in horses. The IR, IP, VS and VM differed between horses and mules, being higher in the horses, but the VD was higher in mules. No difference in the variables in B-mode and Doppler between gender were observed in horses, different from mules, in which the diameters, IR and IP values were higher in males and the VS and VM was higher in females. Body mass did not influence B-Mode, both for horses and mules. A significant correlation was observed for Doppler. The common carotid arteries of horses and mules are different by ultrasound scans B-mode and spectral Doppler. Gender does not influence the B-Mode and Doppler variables in horses, but can in mules. The body mass of horses and mules, regardless of gender, is not associated with B-mode variables, but with Doppler variables.(AU)

B-mode and Doppler ultrasonography in the assessment of the common carotid arteries of equines and mules and the relation with body mass, age and neck circumference / Estudo de ultrassonografia modo-B e Doppler na avaliação das artérias carótidas comuns de equinos e muares e a relação com o peso, idade e a circunferência do pescoço

As age increases, changes in cardiovascular anatomy and physiology occur, even in the absence of disease. Thus, studies of vessel hemodynamics are considered primordial to detect any cardiovascular changes. The objective of this study has been to describe the parameters of B-mode and spectral Doppler ultrasonography in the evaluation of the common carotid arteries of 11 equine and 11 mules, and correlate with age, body mass and neck circumferences. The diameters, intima - media thickness (IMT), resistivity index (RI), pulsatility index (PI), systolic velocity (SV), diastolic velocity (DV), maximum velocity (MV), vascular flow index (VFI), body mass, age, circumference and neck length. Ultrasonographic variables were evaluated in three different region called cranial, middle and caudal. Equine females presented higher values regarding the body mass, age and neck length, as compared to the neck circumferences of the animals, those of the mules were superior. The age of the mules had a positive correlation with the body mass, diameter and neck circumferences, it has a negative correlation between age and vessel diameters. The body mass of the mules had a positive correlation with age and vessel diameters, and with vessel diameters and neck circumferences in equine females. The RI and PI variables had a positive correlation with body mass for mules, and with age for equine females. The DV had a negative correlation with body mass for both equine and mule females. Regarding the variables MV and VFI, age correlated negatively for mules, while it was not significant for equine females. It found a difference between equine females and mules in the correlations performed, with body mass, age, neck circumferences and between B-mode and Doppler ultrasonography variables.(AU)

Com o aumento da idade ocorrem alterações na anatomia e fisiologia cardiovascular, mesmo na ausência de doenças. Assim, os estudos da hemodinâmica dos vasos são considerados primordiais para detectar quaisquer alterações cardiovasculares. Esse trabalho tem como objetivo descrever as variáveis de ultrassonografia modo-B e Doppler espectral na avaliação das artérias carótidas comuns de 11 fêmeas equinas e 11 muares, e correlacionar com idade, massa corpórea e circunferências dos pescoços. Para tais procedimentos foram avaliados os diâmetros, espessura da camada íntima média (EIM), índice de resistividade (IR), índice de pulsatilidade (IP), velocidade sistólica (VS), velocidade diastólica (VD), velocidade máxima (VM), índice de vascularização de fluxo (IVF), massa corpórea, idade, circunferências e comprimentos dos pescoços. As variáveis ultrassonográficas foram avaliadas em três regiões diferentes denominados de crania médio e caudal. As fêmeas equinas apresentaram valores maiores referente ao massa corpórea, idade e comprimento dos pescoços, já em relação às circunferências dos pescoços dos animais, as dos muares foram superiores. A idade dos muares possuiu correlação positiva com a massa corpórea, diâmetro e com as circunferências dos pescoços, com as fêmeas equinas, possui correlação negativa entre idade e os diâmetros dos vasos. A massa corpórea dos muares teve correlação positiva com idade e diâmetros dos vasos, já às fêmeas equinas com diâmetros dos vasos e as circunferências dos pescoços. As variáveis IR e IP tiveram correlação positiva com a massa corpórea para os muares, e com idade para fêmeas equinas. O VD teve correlação negativa com a massa corpórea tanto para as fêmeas equinas quanto nos muares. Já as variáveis VM e IVF, a idade correlacionou negativamente para os muares, enquanto não foi significativo para as fêmeas equinas. Averiguou diferença entre fêmeas equinas e muares nas correlações realizadas, com a massa corpórea, idade, circunferências dos pescoços e entre as variáveis da ultrassonografia modo-B e Doppler.(AU)

Oxidative stress in carotid arteries of patients submitted to carotid endarterectomy. The role of aging process

ABSTRACT PURPOSE: To evaluated the role of oxidative stress on aging process in patients submitted to carotid endarterectomy. METHODS: Twenty patients were divided into two groups: older group (≥ 70 years old); and the younger group (< 70 years old). We evaluated the reactive oxygen species (ROS) concentration, nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase, superoxide dismutase (SOD) and catalase (CAT) activities as so as nitrite levels in fragments of carotid arteries harvested during carotid endarterectomy for treatment of high grade carotid stenosis. RESULTS: We observed a higher levels of ROS and NADPH oxidase activity in the older group (p<0.05). Furthermore, the nitrite concentration was lower in the older group (14.55 ± 5.61 x 10-3 versus 26.42 ± 8.14 x 10-3 µM; p=0.0123). However, the activities of antioxidant enzymes (CAT and SOD) were similar in both the groups. CONCLUSIONS : Arterial aging is associated with increased concentrations of oxygen species and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity as so as nitrite reduction in human carotid artery specimens. Maybe therapies that block NADPH oxidase activity and enhance nitrite stores would be a good strategy to reduce the effect of oxidative stress in arterial aging.

Effects of Omega-3 Fatty Acids on Erectile Dysfunction in a Rat Model of Atherosclerosis-induced Chronic Pelvic Ischemia

The aim of this study was to investigate whether the omega-3 fatty acids help to improve erectile function in an atherosclerosis-induced erectile dysfunction rat model. A total of 20 male Sprague-Dawley rats at age 8 weeks were divided into three groups: Control group (n = 6, untreated sham operated rats), Pathologic group (n = 7, untreated rats with chronic pelvic ischemia [CPI]), and Treatment group (n = 7, CPI rats treated with omega-3 fatty acids). For the in vivo study, electrical stimulation of the cavernosal nerve was performed and erectile function was measured in all groups. Immunohistochemical antibody staining was performed for transforming growth factor beta-1 (TGF-β1), endothelial nitric oxide synthase (eNOS), and hypoxia inducible factor 1-alpha (HIF-1α). In vivo measurement of erectile function in the Pathologic group showed significantly lower values than those in the Control group, whereas the Treatment group showed significantly improved values in comparison with those in the Pathologic group. The results of western blot analysis revealed that systemically administered omega-3 fatty acids ameliorated the cavernosal molecular environment. Our study suggests that omega-3 fatty acids improve intracavernosal pressure and have a beneficial role against pathophysiological consequences such as fibrosis or hypoxic damage on a CPI rat model, which represents a structural erectile dysfunction model.

Determinants of Brachial-Ankle Pulse Wave Velocity and Carotid-Femoral Pulse Wave Velocity in Healthy Koreans

The aim of this study was to determine the normal value of brachial-ankle pulse wave velocity (baPWV) and carotid-femoral pulse wave velocity (cfPWV) according to age group, gender, and the presence of cardiovascular risk factors in healthy Koreans, and to investigate the association between PWV and risk factors such as prehypertension, dyslipidemia, smoking, and obesity. We measured an arterial stiffness in 110 normal subjects who were 20 to 69 yr-old with no evidence of cardiovascular disease, cerebrovascular accident or diabetes mellitus. The mean values of baPWV and cfPWV were 12.6 (+/-2.27) m/sec (13.1+/-1.85 in men, 12.1+/-2.51 in women; P=0.019) and 8.70 (+/-1.99) m/sec (9.34+/-2.13 in men, 8.15+/-1.69 in women; P=0.001), respectively. The distribution of baPWV (P<0.001) and cfPWV (P=0.006) by age group and gender showed an increase in the mean value with age. Men had higher baPWV and cfPWV than women (P<0.001). There was a difference in baPWV and cfPWV by age group on prehypertension, dyslipidemia, current smoking, or obesity (P<0.001). In multiple linear regression, age and prehypertension were highly associated with baPWV and cfPWV after adjustment for confounding factors (P<0.001). The present study showed that baPWV and cfPWV are associated with age, gender, and prehypertension in healthy Koreans.

Intoxicação natural por Solanum glaucophyllum (Solanaceae) em búfalos no Pantanal Matogrossense / Natural poisoning by Solanum glaucophyllum(Solanaceae) in buffaloes in the Brazilian Pantanal

Descreve-se a ocorrência de calcinose enzoótica em búfalos no município de Poconé, Mato Grosso, associado ao consumo de Solanum glaucophyllum (Sg) [=Solanum malacoxylon]. Os casos foram observados entre os anos de 2007 e 2009. Em um rebanho de 40 búfalos, cinco apresentaram emagrecimento progressivo, dorso arqueado, marcha rígida, por vezes com dificuldade para se levantar e locomover, permanecendo apoiando sobre os carpos.Três animais recuperaram-se parcialmente e dois foram eutanasiados in extremis. Os principais achados de necropsia foram calcificação de tecidos moles, principalmente em artérias de grande e médio calibres. A presença de S. glaucophyllum nas pastagens, os sinais clínicos, além dos achados ultrassonográficos e patológicos envolvendo múltiplas calcificações de tendões e outros tecidos, são compatíveis com intoxicação por Solanum glaucophyllum.

This report describes the occurrence of enzootic calcinosis in buffaloes in the municipality of Pocone, Mato Grosso, due to the consumption of Solanum glaucophyllum (Sg) [=Solanum malacoxylon]. The cases were observed in the years 2007 and 2009. In a herd of 40 buffaloes, five showed weight loss, arched back, stiff gait, sometimes difficulty to raise and walk, and leaning on the carpus. Three buffaloes recovered partially and two were euthanized in extremis. The main necropsy findings were calcification of soft tissues, especially of large and medium arteries. The presence of S. glaucophyllum in the pasture, clinical signs, in addition to the sonographic and pathologic calcification involving tendons and other tissues, are consistent with Solanum glaucophyllum poisoning.

Reproducibility of Regional Pulse Wave Velocity in Healthy Subjects

BACKGROUND/AIMS: Despite the clinical importance and widespread use of pulse wave velocity (PWV), there are no standards for pulse sensors or for system requirements to ensure accurate pulse wave measurement. We assessed the reproducibility of PWV values using a newly developed PWV measurement system. METHODS: The system used in this study was the PP-1000, which simultaneously provides regional PWV values from arteries at four different sites (carotid, femoral, radial, and dorsalis pedis). Seventeen healthy male subjects without any cardiovascular disease participated in this study. Two observers performed two consecutive measurements in the same subject in random order. To evaluate the reproducibility of the system, two sets of analyses (within-observer and between-observer) were performed. RESULTS: The means+/-SD of PWV for the aorta, arm, and leg were 7.0+/-1.48, 8.43+/-1.14, and 8.09+/-0.98 m/s as measured by observer A and 6.76+/-1.00, 7.97+/-0.80, and 7.97+/-0.72 m/s by observer B, respectively. Betweenobserver differences for the aorta, arm, and leg were 0.14+/-0.62, 0.18+/-0.84, and 0.07+/-0.86 m/s, respectively, and the correlation coefficients were high, especially for aortic PWV (r=0.93). All the measurements showed significant correlation coefficients, ranging from 0.94 to 0.99. CONCLUSIONS: The PWV measurement system used in this study provides accurate analysis results with high reproducibility. It is necessary to provide an accurate algorithm for the detection of additional features such as flow wave, reflection wave, and dicrotic notch from a pulse waveform.

Los baroquimiorreceptores carotídeos: órganos blanco de la hipertensión arterial / Carotid barochemoreceptors: target organs of arterial hypertension

El cuerpo carotídeo (CC) es el principal quimiorreceptor arterial periférico, capaz de sensar los cambios en la PaO2, la PaCO2 y de pH y transducirlos en señales nerviosas reguladoras de respuestas ventilatorias, circulatorias y endócrinas, que permiten una adaptación a la hipoxemia, la acidosis y la hipercapnia. El seno carotídeo, ubicado próximo al CC, con función barorreceptora, genera respuestas cardiovasculares que descienden la tensión arterial (TA). Ambas estructuras son inervadas por el nervio del seno carotídeo (NSC), que a su vez se proyecta al núcleo del tracto solitario (NTS), y se relacionan íntimamente entre sí y reciben la denominación de baroquimiorreceptores. Últimamente estos órganos se han considerado claves en la regulación de respuestas cardiorrespiratorias homeostáticas que podrían estar íntimamente relacionadas con el desarrollo y el mantenimiento de la hipertensión arterial (HTA). Existe escasa información sobre los cambios estructurales que ocurren en estos órganos durante la HTA y/o como consecuencia de ella. Nuestro planteo es que los baroquimiorreceptores carotídeos representarían un nuevo “órgano blanco” de la HTA. En diversos estudios realizados en seres humanos y en modelos de hipertensión sistólica en animales observamos un daño severo en el CC que se correlacionó significativamente con la elevación de la TA. A su vez, considerando que el sistema renina-angiotensina-aldosterona (SRAA) tendría un papel significativo en la fisiopatología del daño observado, demostramos que el ramipril, versus el atenolol, ejerce un efecto protector sobre el CC más allá de la mera reducción de la TA. Incluso el losartán mostró dicho efecto protector, aun cuando los animales utilizados en los modelos fueron normotensos. Nuestros hallazgos indican que el CC se comporta como un órgano blanco de la HTA y que la activación de un SRAA local sería responsable de los cambios morfológicos y funcionales observados.

The carotid body (CB) is the main peripheral arterial chemoreceptor, able to sense changes in PaO2, PaCO2 and pH, and translate them into nervous signals that regulate ventilating, circulating and endocrine responses which allow adaptation to hypoxemia, acidosis, and hypercapnia. The carotid sinus, located next to the CB, with a baroreceptor function, generates cardiovascular responses that decrease arterial hypertension. Both structures are innervated by the carotid sinus nerve (CSN), which is projected to the solitary tract nucleus (STN), closely inter-related and called barochemoreceptors. Lately, these organs have been considered key in the regulation of homeostatic cardiorespiratory responses that could be intimately related to the development and maintenance of arterial hypertension (AHT). There is scant information on the structural changes that occur in these organs during AHT and/or as its consequence. Our hypothesis is that carotid barochemoreceptors would be a new “target organ” of the AHT. In several studies performed in humans and in models of systolic hypertension in animals we observed a severe damage in the CB which was significantly correlated with elevation of the AT. Hence, considering that the renin-angiotensin-aldosterone system(RAAS) would play a significant role in the pathophysiology of the observed injury, we showed that ramipril versus atenolol has a protective effect on the CB further to the mere decrease of the AT. Even though the animal models used had normal pressure, losartan showed this protective effect. Our findings indicate that the CB behaves as a target organ in AHT and the activation of a local RAAS would be responsible for the morphological and functional changes that were observed.

Carotid arteries in the dog: structure and histophysiology

RESUMEN: El análisis de la estructura de las arterias carótidas, común, externa y interna en el perro sin raza definida, a través del microscopio fotónico mostró variabilidad en los valores promedios de los parámetros: diámetro vascular y grosor de las capas íntima, media y adventicia de cada arteria, respectivamente. El diámetro vascular no difirió significantemente entre las arterias carótidas interna y externa, pero mostró aumento significativo en la arteria carótida común, la cual da origen a los dos otros vasos sanguíneos. El grosor aumentado de las capas íntima y media de la arteria carótida común, más directamente sometida a la fuerza de la presión sistólica cardiaca, significó los ajustes constantes de la pared vascular a las alteraciones de presión y al estrés de deslizamiento controlado entre las capas de la pared arterial. El grosor de la adventicia de la arteria carótida interna fue significativamente mayor que la de las otras arterias carótidas (común y externa), las cuales, entre, sí no tuvieron diferencia con respecto de la adventicia. Estos resultados morfométricos estaban directamente correlacionados con las observaciones morfológicas de naturaleza cualitativa, especialmente, en relación al incremento relativo de la adventicia de la carótida interna ya apreciable en las microfotografías. Tal vez, la adventicia en la arteria carótida interna actúa como una capa conjuntiva protectora, durante el complejo proceso de avance de esta arteria desde su origen cervical hasta el nivel del canal carotídeo donde alcanza la cavidad craneana.

Disipación energética y protección vascular durante la hipertensión arterial sistémica: rol del músculo liso / Energetic dissipation and vascular protection during the systemic arterial hypertension: rol of the smooth muscle

Introducción: las arterias amortiguan las oscilaciones de alta frecuencia de las ondas de presión y flujo disipando energía. El amortiguamiento protege la pared arterial de daños relacionados con dichas oscilaciones. Objetivo: analizar el rol del músculo liso vascular (MLV) en la protección parietal y disipación energética de arterias carótidas (ACC) de sujetos normotensos, hipertensos e hipertensos tratados con inhibidores de la enzima conversora de angiotensina (ECA). Métodos: presión (tonometría) y diámetro (ecografía) carotídeos se registraron en sujetos normotensos (n=12) e hipertensos (n=22) asignados aleatoriamente al tratamiento placebo (n=10) o inhibidores de ECA (ramipril 5-10 mg/día n=12). Se midió in vitro, presión, diámetro en ACC de donantes (n=4; tono vascular nulo), en condiciones hemodinámicas similares a las de los sujetos. Se calculó para cada latido, usando modelización adaptativa, el índice viscoso, elástico e inercial, la energía disipada (Wn) fue mayor (p<0,05) que en los normotensos, mientras que la protección parietal fue similar. Solo en los hipertensos tratados, la Wn se acercó a los valores de los normotensos, sin cambiar la protección parietal. En situación de tono nulo (in vitro) la Wn y la protección parietal fueron menores que en los normotensos (p<0,01), evidenciando la dependencia de estos parámetros con el tono muscular. Conclusión: el sistema arterial mantiene la protección parietal. El MLV protege la pared disipando energía. En hipertensos, la disipación energética aumenta, y se mantiene amortiguamiento y la protección parietal. La disipación energética puede reducirse (tratamiento), disminuyendo la poscarga ventricular y manteniendo la protección arterial.

Acetylcholine and bradykinin enhance hypotension and affect the function of remodeled conduit arteries in SHR and SHR treated with nitric oxide donors

Discrepancy was found between enhanced hypotension and attenuated relaxation of conduit arteries in response to acetylcholine (ACh) and bradykinin (BK) in nitric oxide (NO)-deficient hypertension. The question is whether a similar phenomenon occurs in spontaneously hypertensive rats (SHR) with a different pathogenesis. Wistar rats, SHR, and SHR treated with NO donors [molsidomine (50 mg/kg) or pentaerythritol tetranitrate (100 mg/kg), twice a day, by gavage] were studied. After 6 weeks of treatment systolic blood pressure (BP) was increased significantly in experimental groups. Under anesthesia, the carotid artery was cannulated for BP recording and the jugular vein for drug administration. The iliac artery was used for in vitro studies and determination of geometry. Compared to control, SHR showed a significantly enhanced (P < 0.01) hypotensive response to ACh (1 and 10 æg, 87.9 ± 6.9 and 108.1 ± 5.1 vs 35.9 ± 4.7 and 64.0 ± 3.3 mmHg), and BK (100 æg, 106.7 ± 8.3 vs 53.3 ± 5.2 mmHg). SHR receiving NO donors yielded similar results. In contrast, maximum relaxation of the iliac artery in response to ACh was attenuated in SHR (12.1 ± 3.6 vs 74.2 ± 8.6 percent in controls, P < 0.01). Iliac artery inner diameter also increased (680 ± 46 vs 828 ± 28 æm in controls, P < 0.01). Wall thickness, wall cross-section area, wall thickness/inner diameter ratio increased significantly (P < 0.01). No differences were found in this respect among SHR and SHR treated with NO donors. These findings demonstrated enhanced hypotension and attenuated relaxation of the conduit artery in response to NO activators in SHR and in SHR treated with NO donors, a response similar to that found in NO-deficient hypertension.

Effect of aging on carotid artery stiffness and baroreflex sensitivity during head-out water immersion in man

To examine the possible age-related blood pressure (BP) deregulation in response to central hypervolemia, we measured spontaneous baroreflex sensitivity (SBRS), carotid arterial compliance (CC), and R-R interval coefficient of variation (RRICV) during basal and thermoneutral resting head-out-of-water immersion (HOWI) in 7 young (YG = 24.0 ± 0.8 years) and 6 middle-aged/older (OL = 59.3 ± 1.3 years) healthy men. Compared with basal conditions (YG = 19.6 ± 4.0 vs OL = 6.1 ± 1.5 ms/mmHg, P < 0.05), SBRS remained higher in YG than OL during rest HOWI (YG = 23.6 ± 6.6 vs OL = 9.3 ± 2.1 ms/mmHg, P < 0.05). The RRICV was significantly different between groups (YG = 6.5 ± 1.4 vs OL = 2.8 ± 0.4 percent, P < 0.05) under HOWI. The OL group had no increase in CC, but a significant increase in systolic BP (basal = 115.3 ± 4.4 vs water = 129.3 ± 5.3 mmHg, P < 0.05) under HOWI. In contrast, the YG group had a significant increase in CC (basal = 0.16 ± 0.01 vs water = 0.17 ± 0.02 mm²/mmHg, P < 0.05) with no changes in systolic BP. SBRS was positively related to CC (r = 0.58, P < 0.05 for basal vs r = 0.62, P < 0.05 for water). Our data suggest that age-related vagal dysfunction and reduced CC may be associated with SBRS differences between YG and OL groups, and with BP elevation during HOWI in healthy older men.

Sistema para la medición no invasiva de la velocidad del pulso arterial en diferentes territorios vasculares / A system for non-invasive measurement of arterial pulse velocity different vascular territories

La velocidad de la onda del pulso arterial (VOP) se ha utilizado como índice de rigidez arterial para valorar algunas patologías cardiovasculares. Aquí se describe el diseño y desarrollo de un sistema para determinar la VOP en las regiones aórto-braqui-húmero-radial (A - m), aórto-ileo-fémoro-pedial (A - p) y aórto-carotidea (A - L), el cual se ensayó en 36 sujetos normotensos (NT) y 34 hipertrofia ventricular izquierda (SHVI). El equipo consta de una computadora a la que se le añadió, bajo diseño específico, un convertidor de analógico, bajo diseño específico, un convertidor de analógico a digital y la electrónica y programación para tomar simultáneamante el electrocardiograma (ECG), dos pulsos fotopletismográficos, una lectura de presión y un pulso oscilométrico. Con estos datos se determinó el intervalo Q-pP (tiempo entre la onda Q de ECG y el pie del pulso periférico) lo que, tomando la distancia entre los sitios de registro y luego de calcular el periodo pre-expulsivo cardiaco, permite determinar la VOP (en metros/segundo) desde la raíz de la aorta al punto distal. Al comparar la VOP en HT vs NT (A - m: 9.3 ñ 2.6 vs. 7.2 ñ 0.8, A - L: 9.5 ñ 2.8 vs. 6.0 ñ 0.9 y A - p: 9.5 ñ 1.8 vs. 7.2 ñ 0.9), la diferencia resultó significativa (p < 0.001) en cada uno de los territorios explorados; lo mismo ocurrió al comparar los casos CHVI contra los SHVI (A - m: 10.5 ñ 1.6 vs. 8.0 ñ 1.9, A - L: 10.2 ñ 1.9 vs 8.0 ñ 1.9 y A - p: 10.5 ñ 2.0 vs. 8.6 ñ 1.2) (p < 0.025). Esto es consistente con la conocida relación mayor presión - mayor rigidez y con lo reportado en otros trabajos que utilizan métodos diferentes para precisar la VOP. El método puede tener aplicación en la clínica

Avaliaçäo da açäo concomitante do baläo intra-aórtico e da bomba centrífuga na assistência ao ventrículo esquerdo: estudo experimental em cäes / Evaluation of intraaortic balloon pump associated with centrifugal pump for left ventricular assistance: an esperimental study in dogs

Mechanical assist ventricular devices have been used in the treatment of low cardiac output syndrome. These devices can be generically grouped in pulsatile and nonpulsatile. There is a great controversy about the advantages and disadvantages of each one of these groups. The objective of this paper is to evaluate the influence of the centrifugal pump used for left ventricular assistance on the coronary and carotid flow in dogs with normal heart. The efficacy of the simultaneous use of an intraaortic balloon pump to compensate the possible deleterious effects of the circulatory assistance with continuous flow was analysed. Fifteen dogs with a mean weight of 16.3 kg were studied. Hemodynamic evaluation included serial measurements of pressures of the right atrium, pulmonary capillary wedge, pulmonary artery, systemic arterial circulation and heart rate. Cardiac output was measured and the following derived hemodynamic parameters were calculated: cardiac index, systolic index, systemic vascular resistance and pulmonary vascular resistance. Carotid and coronary blood flow were obtained by electromagnetic tranducers. The parameters were analysed in four situations: S1. Standard situation; S2. Test situation - the centrifugal pump as a left ventricular assist device; S3. Test situation - the centrifugal pump associated with intraaortic balloon pump; S4. Final situation, where the intraaortic balloon is turned off to confirm its influence. The hemodynamic evaluation didn't show significant statistic changes in the analysed parameters in the four situations. In relation to the coronary flow, however, the use of circulatory isolated assistence with centrifugal pump (S2 and S4) displayed a reduction (24.6 per cent ñ 6.1) in relation to the standard situation - S1 as much as to the associated intraaortic balloon - S3 (p = 0.0079); S1 and S3 showed similar coronary flow. In relation to the carotid flow, the profile analysis suggests the existence of a difference between the multiple situations, but it is not significant (p = 0.0582)...

Effect of chronic estradiol administration on the acute pressor response to aortic coarctation in conscious rats

We investigated the effect of chronic estradiol administration on the pressor response elicited by acute (45 min) partial aortic constriction in conscious Wistar rats and on vascular reactivity to angiotensin II and vasopressin in vitro. Estradiol or vehicle was administered for 7 days to young castrated male and female rats and to female rats that had stopped cycling. In the acute experiment of aortic coarctation in concious rats, carotid pressure was monitored continuously before and for 45 min after partial abdominal aortic coarctation. In ovariectomized females the mean carotid pressure and heart rate before aortic coarctation were significantly lower in estradiol treated animals. Estradiol did not affect the pressor response to aortic coarctation of castrated male rats or ovariectomized female rats but blunted the reflex bradycardia of ovariectomized rats. The onset of the pressor response to aortic coarctation was delayed in aged female rats as compared to the other groups. While estradiol treatment significantly accelerated the onset of hypertension in aged rats, it did not affect the pressor response of castrated animals. Full dose-response curves to angiotensin II and vasopressin were constructed in vitro in the isolated mesenteric arterial bed obtained from similary treated groups. Estradiol did not affectthe vasopressin sensitivity or responsiveness of any group, but caused a significant increase in angiotensin II sensitivity in ovariectomized rats only. In conclusion, these data slow that chronic estradiol administration ot aged female rats accelerate the installation of the pressor response to acute aortic coarctation. In addition, estradiol administration to ovariectomized rats is associated with lower blood pressure and heart rate.

Blood compatibility of tubular polymeric materials studied by biological surface interactions

Tubular polymeric materials modified by radiation techniques can be used as vascular prosthesis and components of prosthetic devices. The biological interction between these materials and blood was studied by in vitro and ex vivo methods. Silicone rubber tubes were copolymerized with acrylamide and N-vinylpyrrolidone by radiation-grafting techniques. The irradiation was performed with y-rays from a 60Co source at a constant dose rate (0.2 kGy/h) for various time intervals (4-15 h). To evaluate the antithrombogenicity of the grafted tubes, the surface adsorption of 125I-albumin and 125I-fibrinogen was studied. All graft copolymers show a preference for albumin, and the degree of preference appears to correlate with antithrombogenic tendency. In the ex vivo experiment with animals, tubes were implanted in the carotid artery of dogs and the blood flow in the graft copolymers was detected with an ultrasonic flow meter. The blood flow rate in the ungrafted implants decreased more rapidly (stopped completely after 15 to 210 min) compared to the flow rate in the grafted ones (decreased slowly from 38 to 35 ml/min and 70 to 60 ml/min). There was a direct relationship between both methods in the study of blood compatibility of the materials. The results suggest that the graft copolymers can be used as biomaterials for long-term use in cardiovascular systems