Comparative Study of Capillary Filtration Coefficient (Kfc) Determination by a Manual and Automatic Perfusion System. Step by Step Technique Review.

The purpose of calculating the capillary filtration coefficient is to experimentally evaluate edema formation in models of pulmonary ischemia-reperfusion injury. For many years, the obtaining of this coefficient implies a series of manual maneuvers during ex-vivo reperfusion of pulmonary arterial pressure, venous pressure and weight, as well as the calculation of the Kfc formula. Through automation, the calculation of capillary filtration coefficient could be easier and more efficient. To describe an automatic method designed in our laboratory to calculating the capillary filtration coefficient and compare with traditional determination of capillary filtration coefficient as gold standard method. An automatic three valve perfusion system was constructed, commanded by a mastery module connected to a graphical user interface. To test its accuracy, cardiopulmonary blocks of Wistar rats were harvested and distributed in manual (n=8) and automated (n=8) capillary filtration coefficient determination groups. Physiological parameters as pulmonary arterial pressure, pulmonary venous pressure, weight and capillary filtration coefficient were obtained. Results: Capillary filtration coefficient, pulmonary arterial pressure, venous arterial pressure shown no statistical significance difference between the groups. The automated perfusion system for obtaining Kfc was standardized and validated, giving reliable results without biases and making the process more efficient in terms of time and personal staff.

Purinergic receptor stimulation induces calcium oscillations and smooth muscle contraction in small pulmonary veins.

KEY POINTS: We investigated the excitation-contraction coupling mechanisms in small pulmonary veins (SPVs) in rat precision-cut lung slices. We found that SPVs contract strongly and reversibly in response to extracellular ATP and other vasoconstrictors, including angiotensin-II and endothelin-1. ATP-induced vasoconstriction in SPVs was associated with the stimulation of purinergic P2Y2 receptors in vascular smooth muscle cell, activation of phospholipase C-ß and the generation of intracellular Ca2+ oscillations mediated by cyclic Ca2+ release events via the inositol 1,4,5-trisphosphate receptor. Active constriction of SPVs may play an important role in the development of pulmonary hypertension and pulmonary oedema. ABSTRACT: The small pulmonary veins (SPVs) may play a role in the development of pulmonary hypertension and pulmonary oedema via active changes in SPV diameter, mediated by vascular smooth muscle cell (VSMC) contraction. However, the excitation-contraction coupling mechanisms during vasoconstrictor stimulation remain poorly understood in these veins. We used rat precision-cut lung slices and phase-contrast and confocal microscopy to investigate dynamic changes in SPV cross-sectional luminal area and intracellular Ca2+ signalling in their VSMCs. We found that the SPV (∼150 µm in diameter) contract strongly in response to extracellular ATP and other vasoconstrictors, including angiotensin-II and endothelin-1. ATP-induced SPV contraction was fast, concentration-dependent, completely reversible upon ATP washout, and inhibited by purinergic receptor antagonists suramin and AR-C118925 but not by MRS2179. Immunofluorescence showed purinergic P2Y2 receptors expressed in SPV VSMCs. ATP-induced SPV contraction was inhibited by phospholipase Cß inhibitor U73122 and accompanied by intracellular Ca2+ oscillations in the VSMCs. These Ca2+ oscillations and SPV contraction were inhibited by the inositol 1,4,5-trisphosphate receptor inhibitor 2-APB but not by ryanodine. The results of the present study suggest that ATP-induced vasoconstriction in SPVs is associated with the activation of purinergic P2Y2 receptors in VSMCs and the generation of Ca2+ oscillations.

Avaliação ecocardiográfica da função atrial esquerda: aspectos fisiológicos e clínicos / Echocardiographic evaluation of left atrial function: physiological and clinical aspects / Evaluación Ecocardiográfica de la Función Atrial Izquierda: Aspectos Fisiológicos y Clínicos

A avaliação da função atrial esquerda pode proporcionar informações importantes relacionadas à fisiopatologia de muitas cardiopatias, principalmente quando o envolvimento é das cavidades esquerdas. Entretanto, ao contrário das funções sistólica e diastólica do ventrículo esquerdo, amplamente exploradas em muitas condições clínicas, a função do átrio esquerdo é, ainda, pouco estudada.Conceitos básicos das funções de reservatório, de conduto e de bomba do átrio esquerdo são discutidos, destacando as relações com enchimento ventricular. Métodos de investigação dessas funções são apresentados de forma resumida.

La evaluación de la función atrial izquierda puede proporcionar informaciones importantes relacionadas a la fisiopatología de muchas cardiopatías, principalmente cuando el envolvimiento es de las cavidades izquierdas. Mientras tanto, al contrario de las funciones sistólica y diastólica del ventrículo izquierdo, ampliamente exploradas en muchas condiciones clínicas, la función del atrio izquierdo es, aun, poco estudiada.Conceptos básicos de las funciones de depósito, de conducto y de bomba del atrio izquierdo son discutidos, destacando las relaciones con llenado ventricular. Métodos de investigación de esas funciones son presentados de forma resumida...

The evaluation of left atrial function may provide important information regarding the pathophysiology of many heart diseases, especially when the left chambers are involved. However, as opposed to the left ventricular systolic and diastolic functions, widely exploited in many clinical conditions, the left atrial function is still poorly studied. Basic concepts of the functions of left atrial reservoir, conduit and booster pump are discussed, highlighting the connections with ventricular filling. The methods of investigation of these functions are presented in summary form...

Behavior of pulmonary venous flow during fetal respiratory movements.

OBJECTIVE: To test the hypothesis that fetal pulmonary venous flow pulsatility index is lower during fetal respiratory movements than in apnea. DESIGN: Case control. SETTINGS/PATIENTS: Twenty-two normal fetuses of mothers without systemic disease were examined in apnea (controls) and in the presence of fetal respiratory movements (cases). Fetuses were examined by prenatal Doppler echocardiography with color flow mapping. The pulsatility index of the pulmonary vein was obtained by placing the pulsed Doppler sample volume over the right upper or left lower pulmonary vein, and calculating the ratio (maximum velocity [systolic or diastolic]-presystolic velocity/mean velocity). RESULTS: Mean gestational age was 28.9 +/- 2.9 weeks. During fetal apnea, mean systolic, diastolic, and presystolic velocities were, respectively, 0.35 +/- 0.08 m/s, 0.26 +/- 0.07 m/s, and 0.09 +/- 0.03 m/s. In the presence of fetal respiratory movements, mean systolic, diastolic, and presystolic velocities were, respectively, 0.33 +/- 0.1 m/s, 0.28 +/- 0.08 m/s, and 0.11 +/- 0.04 m/s. Pulsatility index pulmonary vein in apnea was 1.25 +/- 0.23 (1.69 to 0.82), and during fetal respiratory movements it was 0.97 +/- 0.2 (1.53 to 0.61). CONCLUSION: We showed a significant reduction in impedance of pulmonary venous flow, represented by pulmonary vein pulsatility index, during fetal respiratory movements, reflecting modifications of the left atrial dynamics and enhancement of left ventricular compliance.

Avaliação ecodopplercardiográfica da função diastólica em cães da raça Boxer / Ecodopplercardiographic evaluation of diastolic function in Boxer dogs

Foram avaliados os principais índices diastólicos, inclusive a velocidade de propagação mitral (Vp), em 36 cães sadios da raça Boxer, 18 de cada sexo, de idade entre um ano e meio e seis anos. A relação raiz aórtica e átrio esquerdo medida no modo B foi de 1,17±0,11. Os picos de velocidades das ondas de enchimento atrial esquerdo foram: sistólica 31,41±6,87cm/s, diastólica (D) 73,85±17,04cm/s e de reversão atrial 28,90±8,33cm/s. A relação das ondas de enchimento ventricular inicial (E) e atrial (A) foi 1,58±0,19 na valva mitral e de 1,62±0,29 na valva tricúspide. Entre os índices avaliados, a Vp só se correlacionou fracamente (r=0,39) com as ondas E e A mitrais e com a onda D, mostrando-se um índice, relativamente, independente. A Vp não apresentou diferença significativa entre os sexos nem entre examinadores. A Vp diminuiu com o aumento da idade e exibiu valor médio, neste estudo, de 99,73±16,06cm/s(AU)

Major diastolics indexes, including the mitral propagation velocity (Vp), were evaluated in 36 healthy Boxer dogs, 18 males and 18 females, aging from 1.5 to 6-years-old. The aortic root and left atrium ratio, measured in B mode, was 1.17±0.11. The peaks of velocity of waves of the left atrium filling were: systolic 31.41±6.87cm/s, diastolic 73.85±17.04cm/s and atrial reversal 28.90±8.33cm/s. The ratios of the waves of initial ventricular filling were 1.58±0.19 to mitral valve and 1.62±0.29 to tricuspid valve. From the evaluated indexes, the Vp was only weakly correlated (r=0.39) with E and A waves of mitral valve and with D, showing itself, relativity, as an independence index. Regarding to the Vp, no significant differences were seen between the gender of the animals and among the observers. The Vp decreased as the age increased, showing mean values of 99.73±16.06cm/s(AU)

Avaliação ecodopplercardiográfica da função diastólica em cães da raça Boxer / Ecodopplercardiographic evaluation of diastolic function in Boxer dogs

Foram avaliados os principais índices diastólicos, inclusive a velocidade de propagação mitral (Vp), em 36 cães sadios da raça Boxer, 18 de cada sexo, de idade entre um ano e meio e seis anos. A relação raiz aórtica e átrio esquerdo medida no modo B foi de 1,17±0,11. Os picos de velocidades das ondas de enchimento atrial esquerdo foram: sistólica 31,41±6,87cm/s, diastólica (D) 73,85±17,04cm/s e de reversão atrial 28,90±8,33cm/s. A relação das ondas de enchimento ventricular inicial (E) e atrial (A) foi 1,58±0,19 na valva mitral e de 1,62±0,29 na valva tricúspide. Entre os índices avaliados, a Vp só se correlacionou fracamente (r=0,39) com as ondas E e A mitrais e com a onda D, mostrando-se um índice, relativamente, independente. A Vp não apresentou diferença significativa entre os sexos nem entre examinadores. A Vp diminuiu com o aumento da idade e exibiu valor médio, neste estudo, de 99,73±16,06cm/s

Major diastolics indexes, including the mitral propagation velocity (Vp), were evaluated in 36 healthy Boxer dogs, 18 males and 18 females, aging from 1.5 to 6-years-old. The aortic root and left atrium ratio, measured in B mode, was 1.17±0.11. The peaks of velocity of waves of the left atrium filling were: systolic 31.41±6.87cm/s, diastolic 73.85±17.04cm/s and atrial reversal 28.90±8.33cm/s. The ratios of the waves of initial ventricular filling were 1.58±0.19 to mitral valve and 1.62±0.29 to tricuspid valve. From the evaluated indexes, the Vp was only weakly correlated (r=0.39) with E and A waves of mitral valve and with D, showing itself, relativity, as an independence index. Regarding to the Vp, no significant differences were seen between the gender of the animals and among the observers. The Vp decreased as the age increased, showing mean values of 99.73±16.06cm/s

[Functional anatomy of the junction of the left atrium and the pulmonary veins]. / Anatomia funcional da junção entre o átrio esquerdo e as veias pulmonares.

PURPOSE: To study the spatial arrangement of the bundles of myocardial fibers presents in the left atrial-venous junctions and in the wall of the pulmonary veins. METHODS: The study was made on 24 human adult hearts, together with pulmonary vessels, fixed in 10% formaldehyde solution. Each specimen was cleared of remnants of pericardium to expose the myocardial fibers as clearly as possible. Particular attention was paid to the atrial-venous junction and the extension of the myocardial fibers in the pulmonary veins. The specimens were embedded in celloidin and cut serially at a thickness of 70 mu and stained by methods of Azan's trichrome. RESULTS: The myocardial bundles leave the atrial wall around the openings of all pulmonary veins forming a sphincter-like structure. These fibers are continuous in the adventitial coat running in oblique or spiral directions. Some bundles, more external, leaving from the atrial wall, surround the ostium of the veins and return to the atrium, forming true loops. CONCLUSION: The extremities of the pulmonary veins and their junctions with the atrium have a morphological substract which may be of physiological importance in the control of the pulmonary venous pressure and blood flow.

Anatomia funcional da junção entre o átrio esquerdo e as veias pulmonares / Functional Anatomy of the Junction Between the Left Atrium and The Pulmonary Veins

PURPOSE--To study the spatial arrangement of the bundles of myocardial fibers presents in the left atrial-venous junctions and in the wall of the pulmonary veins. METHODS--The study was made on 24 human adult hearts, together with pulmonary vessels, fixed in 10 per cent formaldehyde solution. Each specimen was cleared of remnants of pericardium to expose the myocardial fibers as clearly as possible. Particular attention was paid to the atrial-venous junction and the extension of the myocardial fibers in the pulmonary veins. The specimens were embedded in celloidin and cut serially at a thickness of 70 mu and stained by methods of Azan's trichrome. RESULTS--The myocardial bundles leave the atrial wall around the openings of all pulmonary veins forming a sphincter-like structure. These fibers are continuous in the adventitial coat running in oblique or spiral directions. Some bundles, more external, leaving from the atrial wall, surround the ostium of the veins and return to the atrium, forming true loops. CONCLUSION--The extremities of the pulmonary veins and their junctions with the atrium have a morphological substract which may be of physiological importance in the control of the pulmonary venous pressure and blood flow

[Effects of venous segment pressure on the critical closure pressure, in the isolated lung lobe from dogs in situ]. / Efecto de la presión del segmento venoso sobre la presión crítica de cierre, en el lóbulo canino aislado in situ.

In an isolated in situ canine left lower lobe preparation we studied the influence of the distal vascular compartment or venous pressure (PV) on the pressure of arterial vascular segment at zero flow or minimal critical closing pressure (MCCP), while alveolar pressure was held constant and below MCCP. The MCCP-PV curve showed an independent segment when PV was less than 8 mmHg. Above this value (that we define as PV), an slope of 1.08 was found. Our findings indicate that MCCP is not MCCP if PV greater than 8 mmHg (it is MCCP). Because MCCP is higher than alveolar pressure, MCCP must be the back pressure for flow. This finding is not in disagreement with the new concept regarding that MCCP is the back pressure for flow and not alveolar pressure in West's zone II condition.

Color flow mapping to document normal pulmonary venous return in neonates with persistent pulmonary hypertension being considered for extracorporeal membrane oxygenation.

This study investigated the value of color flow mapping in documenting normal pulmonary venous return in neonates with persistent pulmonary hypertension who were candidates for extracorporeal membrane oxygenation (ECMO). Forty newborn infants with persistent pulmonary hypertension underwent conventional (two-dimensional and Doppler) echocardiography and color flow mapping. Of 25 candidates for ECMO therapy, 18 subsequently received it. Conventional echocardiography demonstrated normal pulmonary venous return in only 21 of the 40 patients. In all 40, however, color flow mapping demonstrated normal right and left pulmonary venous drainage entering the left atrium. In three other patients with total anomalous pulmonary venous return, conventional echocardiography demonstrated the anomalous pulmonary venous pathways, and color flow mapping did not show jets emanating from the left atrial wall; the left atrium was shown to fill exclusively from right to left shunting through the foramen ovale. We conclude that color flow mapping is superior to conventional echocardiography for verifying normal pulmonary venous return in neonates with persistent pulmonary hypertension.