A case of absent right and persistent left superior vena cava

BACKGROUND AND PURPOSE: Our case report deals with the importance of detailed echocardiographic examination for differential diagnosis of coronary sinus dilation and development of abnormalities of great thoracic veins. CASE PRESENTATION: A 49-year-old man underwent transthoracic echocardiography for atypical chest pain. A dilated coronary sinus was found and venous contrast echocardiography raised the suspicion of absent right and persistent left superior vena cava. Transesophageal echocardiography showed absence of right superior vena cava. The echocardiographic findings were confirmed by upper venous digital subtraction cavography. CONCLUSION: combination of agenesia of right SVC and isolated persistent left SVC in adult patients is a very rare abnormality. Both clinicians and sonographers should be alerted to the possible presence of this combined venous anomaly. Transthoracic echocardiograpy – including agitated saline infusion to the antecubital vein – is an important diagnostic tool for accurate diagnosis of this congenital thoracic venous malformation

Gene expression in cardiac tissues from infants with idiopathic conotruncal defects

<p>Abstract</p> <p>Background</p> <p>Tetralogy of Fallot (TOF) is the most commonly observed conotruncal congenital heart defect. Treatment of these patients has evolved dramatically in the last few decades, yet a genetic explanation is lacking for the failure of cardiac development for the majority of children with TOF. Our goal was to perform genome wide analyses and characterize expression patterns in cardiovascular tissue (right ventricle, pulmonary valve and pulmonary artery) obtained at the time of reconstructive surgery from 19 children with tetralogy of Fallot.</p> <p>Methods</p> <p>We employed genome wide gene expression microarrays to characterize cardiovascular tissue (right ventricle, pulmonary valve and pulmonary artery) obtained at the time of reconstructive surgery from 19 children with TOF (16 idiopathic and three with 22q11.2 deletions) and compared gene expression patterns to normally developing subjects.</p> <p>Results</p> <p>We detected a signal from approximately 26,000 probes reflecting expression from about half of all genes, ranging from 35% to 49% of array probes in the three tissues. More than 1,000 genes had a 2-fold change in expression in the right ventricle (RV) of children with TOF as compared to the RV from matched control infants. Most of these genes were involved in compensatory functions (e.g., hypertrophy, cardiac fibrosis and cardiac dilation). However, two canonical pathways involved in spatial and temporal cell differentiation (WNT, <it>p </it>= 0.017 and Notch, <it>p </it>= 0.003) appeared to be generally suppressed.</p> <p>Conclusions</p> <p>The suppression of developmental networks may represent a remnant of a broad malfunction of regulatory pathways leading to inaccurate boundary formation and improper structural development in the embryonic heart. We suggest that small tissue specific genomic and/or epigenetic fluctuations could be cumulative, leading to regulatory network disruption and failure of proper cardiac development.</p

Endothelium-dependent relaxations of piglet pulmonary arteries augment with maturation

To determine whether maturation alters endothelium-dependent responses in porcine pulmonary arteries, rings, with and without endothelium, of small pulmonary arteries taken from piglets of 3, 10, and 30 d of age were suspended in organ chambers filled with buffered salt solution, bubbled with 95% O2-5% CO2, and maintained at 37°C. These studies were performed in the presence of indomethacin (10-5 M) to inhibit prostaglandin synthesis. In rings without endothelium, potassium chloride (10-2 to 8.5 x 10-2 M) and histamine (10-9 to 10-5 M) caused concentration-dependent contractions. When normalized to maximal contractions achieved to each agonist, the concentration-effect curves to potassium chloride and histamine in rings without endothelium were similar at each age. Rings with endothelium showed a progressive shift to the right of the concentration-effect curve to histamine, possibly secondary to an increase in the basal release of, or responsiveness to, the endothelium-derived relaxing factor with maturation. Relaxations to sodium nitroprusside (10-9 to 10-5 M) were unaffected by age. In precontracted rings, acetylcholine (10-9 to 10-6 M), bradykinin (10-10 to 10-6 M), and the calcium ionophore A23187 (10-9 to 10-6 M) caused relaxations in rings with endothelium, but not in those without endothelium, which were greater at 10 and 30 d compared to 3 d; further augmentation at 30 d compared to 10 d was not observed. In rings without endothelium, changes in the responsiveness to nitric oxide (10-9 to 10-5 M), one of the proposed endothelium-derived relaxing factors, with age were comparable to those observed with endothelium-dependent relaxing agents. These studies demonstrate that endothelium-dependent relaxations increase with age, possibly due to changes in sensitivity of the smooth muscle to the endothelium-derived relaxing factor.link_to_subscribed_fulltex

Heterogeneity of endothelium-dependent and independent responses among large and small porcine pulmonary arteries

To determine whether heterogeneity of endothelium-dependent or independent responsiveness exists between large and small pulmonary arteries, isolated rings (3-4 mm long) from large (5-7 mm in diameter) and small (2-3 mm in diameter) intralobar pulmonary arteries were prepared from normal swine and studied in vitro. Rings, with and without endothelium, were suspended in modified Krebs-Ringer bicarbonate solution, bubbled with 95% O2-5% CO2, maintained at 37°C and studied in parallel. Contractions to phenylephrine, norepinephrine and histamine were significantly potentiated in small rings, with or without endothelium, compared to large pulmonary artery rings with or without endothelium. The α-adrenergic agonist, UK 14304, however, caused comparable contractions in rings without endothelium taken from large and small vessels. Contractions to potassium chloride in rings without endothelium were also comparable. Relaxant responses were assessed in rings incubated with indomethacin and contracted with phenylephrine or prostaglanding F(2α). Acetylcholine, bradykinin, the calcium ionophore A23187 and UK 14304 elicited endothelium-dependent relaxations in rings from both large and small vessels. Relaxations induced by acetylcholine and bradykinin but not those by A23187 were significantly shifted downward in small versus large pulmonary-artery rings. Isoproterenol also caused endothelium-augmented relaxations but in rings from small vessels only. Sodium nitroprusside and nitric oxide caused similar relaxations in rings from both orders. These results demonstrate that a heterogeneity in endothelium-dependent and independent responsiveness exists between large and small pulmonary arteries.link_to_subscribed_fulltex

Prostacyclin-induced relaxations of small porcine pulmonary arteries are enhanced by the basal release of endothelium-derived nitric oxide through an effect on cyclic GMP-inhibited-cyclic AMP phosphodiesterase

AIM: To study the interactions between prostacyclin and endothelium- derived nitric oxide in porcine pulmonary arteries. METHODS: Rings of 5th order of porcine pulmonary arteries were studied in vitro for the measurement of tension and the content in cyclic nucleotides. RESULTS: Prostacyclin, given exogenously, caused endothelium-potentiated relaxations (inhibition of phenylephrine contraction) that were inhibited by the inhibitors of the L- arginine nitric oxide pathway, oxyhemoglobin and N(ω)-nitro-L-arginine. These inhibitors did not affect the tension in rings without endothelium. Cyclic GMP-concentrations were not increased above basal concentrations in the presence of prostacyclin. Increases were seen with acetylcholine and sodium nitroprusside. Prostacyclin-stimulated cyclic AMP concentrations did not reach statistical significance compared to controls. The addition of 8- bromo-cyclic GMP to prostacyclin, however, increased the cyclic AMP content. The nitric oxide synthase inhibitor, nitro-L-arginine (NLA), reduced the prostacyclin-stimulated cyclic AMP content to basal level. Inhibition of cyclic GMP-inhibited cyclic AMP phosphodiesterase by 8-bromo-cyclic GMP or amrinone (a specific inhibitor of this enzyme) potentiated the prostacyclin- induced relaxations in rings without endothelium to a magnitude similar to that observed in rings with endothelium. CONCLUSION: These data suggest that the augmentation by the endothelium of the prostacyclin-induced relaxation of porcine pulmonary arteries is secondary to the inhibition of cyclic GMP- inhibited cyclic AMP phosphodiesterase by basally released endothelium- derived nitric oxide.link_to_subscribed_fulltex

Heterogeneity of endothelium-dependent and endothelium-independent responses to aggregating platelets in porcine pulmonary arteries

Experiments were designed to determine the endothelium-dependent and endothelium-independent responses to aggregating platelets in porcine pulmonary arteries. Isolated rings with and without endothelium from large (5-7-mm-diameter) and small (2-3-mm-diameter) pulmonary arteries were suspended in modified Krebs-Ringer bicarbonate solution bubbled with 95% O2-5% CO2 in the presence of indomethacin. Aggregating platelets caused relaxations in rings with endothelium but contractions in rings without endothelium, both of which were significantly larger in small versus large pulmonary artery rings. Serotonin and ADP caused concentration-dependent endothelium-augmented relaxations that were unaffected by ketanserin. Methiothepin, but not apyrase, significantly decreased the platelet-induced endothelium-dependent relaxations; the residual relaxation was abolished when rings were incubated with methiothepin, apyrase, and theophylline but was unaffected if apyrase was absent, indicating that ADP is responsible for the residual relaxation caused by aggregating platelets. Quiescent rings, with and without endothelium, contracted in a dose-dependent manner to norepinephrine and histamine but not to serotonin or vasopressin. The contraction to aggregating platelets was blocked by methiothepin, pyrilamine, and diphenhydramine but was unaffected by phentolamine, ketanserin, or incubation of the platelets with dazoxiben. These data indicate that, in large and small porcine pulmonary arteries, serotonin and ADP are the major contributors to the endothelium-dependent relaxation caused by aggregating platelets, while histamine appears to be responsible for the contraction that platelets cause in rings without endothelium.link_to_subscribed_fulltex